Hi all, I need some help trouble shooting an HTPS 7000 MKII. This is isolater/filter that has multiple uses. It arrived two days ago and doesn't power up. Generally, it is pretty well built. I removed the top cover and didn't see anything immediatly that stood out. However it does have a strong electronic smell around the main power supply board which resides by the two torroids. It is not an ozone smell, rather a deeper type burnt smell also like a burn in smell. Now I"m wondering if the chips are fried in it.
Put it on a variac and added a fuse to F402. plugged it in and attempted to turn it on. Fuse blows. A few more times attempting to isolate the problem. Completely isolated the P/S board and the main fault lies there, somewhere. Currently I have it where I can keep it from blowing a 1 amp fuse in the F402 position by putting a 100 watt bulb in series with the unit. At about 15 VAC the bulb starts illuminating and remains that way up to 120 VAC. I don't want to keep it that way so I tried to find the fault at 30 VAC so far haven't found it.
There are a lot of little chips that not easily accessed with the unit assembled. So I'll have to pull the board again for testing. My guess is one or more of the chips is shorted but not sure which one and don't have a schematic. The manufacturer, Monster, refused to provide me with a schematic as it is not their policy, they stated they won't fix it. I tried to explain to them that is what I was going to do, fix it and need a schematic. I've not had problems obtaining schematics from other well known companies, Fluke, HP, Mesa, Fender, Peavey, etc. So it will take some time for me to get up the learning curve. Here are some pariculars
Power Board: PC Board T2, 7000 MKI Issue 1, REV 1 Here is a list of the chips: Philips 5349 MOC3083 MJE13005F JC448 L78L05 1N4742 MPSA42 Mystery 7MK2-T142 (looks like a quad opamp?) The Zeners 1N4742 look to have been over heated as they are no longer orange and black but grey silver. I'm going to try searching for data sheets. I am not here to bash anyone or any thing. Just documenting what I find and how to go about fixing something that might be of help to others in the same situation. Anyone with experience with these units I would appreciate some assistance and guidance.
Thanks in advance.
I have some Pics and I post as I can get them out of the camera, alsways a challenge. iPhone pics while convenient are typically blurred for some reason. Here are pics of the unit.
Front:
Top down view:
Board view:
]
Board back view:
The back of this board had crap all over it. I wiped it clean with ISO-OH. It cleaned up nice and shiny while the wipes were brown. Smoke from something that burned or was it Tars from being in a smoke filled room? Doing some basic measurement with the board removed: Upper center board: Two 5W Cement resistors 62K and 39K measured abnout 1 ohm. The diodes and the resistors didn't read correctly.
The diodes read in both directions, .547 on the resistor check and 1.08 the incorrect direction. Pulled one leg up on each, and the resistors measured properly. Do did the diodes. I replaced the diodes just in case, didn't need to because the new one measured the same when installed. Next came the the two watt resistors to the center right. These were 330ohm and 560 ohm wired in series. 330 ohm were find but when checking 560 ohm they were both open.
Pulled a leg each with the same result, open. Removed them and meausred them. 560 Ohm each. WTF over? Turned my meter off and on meausred 560 ohm. Decided to replace them with 600 ohm 2 watt dale wire wound that I had on hand. Reinstalled board, same result...still have the burning 100 watt bulb. Found some of the problem by letting the unit warm up. It appears the MJE13005F and the JC448 are the problems as they are both on a heat sink. at about 15 mins at 60V with the 100 watt bulb...the heat sink burns to the touch.
It might also explain why have have AC on both sides of F401 fuse when the fuse is NOT installed. I don't know why they fried though and that worries me. Wondering what else they take with them? 1N4742 zeeners show signs of heat problem. More pics soon. Update on Data sheets: Philips 5249 is a BT136 Triac, 600V 4 Amp. JC448 my bad is a MJE13003 or 2SA1709/2SC4489 NPN my guess is the MJE13003 and/or 2SC4489 NPNHV Switch. 700Vdc peak, from Ic 1.5 Acd, Ib .75 Adc, Ie 2.25 Adc continuous. MOC 3083 is an opto Isolator powered by 240 VAC. 4n35 are opto couplers w/input to output peak @ 3.55KV. The specs on these are pretty beefy though. These things are pretty beefy, I hope it isn't that quad opamp that fried.... Light of my life:
Voltage Reading:
Focused Board Closeup:
Update, Well as long as I'm here and going to pull the board again might as well shot gun it. First though I'll pull the mystery chip...just to be sure and then see if it still pulls current. That will rule out that part of the PS I'm thinking. Then, I'll pull the SS units and go from there. NOTE: When you link pics from the Gallery here for some reason I don't have ability to zoom in. : ( I was wrong again on some of the parts. Some of the parts I couldn't find readily but will substitue some of them. For some of the parts I wonder if it hasn't been already replaced with a lower speced part before I got it. I don't know. As I don't have a resource.
Put it on a variac and added a fuse to F402. plugged it in and attempted to turn it on. Fuse blows. A few more times attempting to isolate the problem. Completely isolated the P/S board and the main fault lies there, somewhere. Currently I have it where I can keep it from blowing a 1 amp fuse in the F402 position by putting a 100 watt bulb in series with the unit. At about 15 VAC the bulb starts illuminating and remains that way up to 120 VAC. I don't want to keep it that way so I tried to find the fault at 30 VAC so far haven't found it.
There are a lot of little chips that not easily accessed with the unit assembled. So I'll have to pull the board again for testing. My guess is one or more of the chips is shorted but not sure which one and don't have a schematic. The manufacturer, Monster, refused to provide me with a schematic as it is not their policy, they stated they won't fix it. I tried to explain to them that is what I was going to do, fix it and need a schematic. I've not had problems obtaining schematics from other well known companies, Fluke, HP, Mesa, Fender, Peavey, etc. So it will take some time for me to get up the learning curve. Here are some pariculars
Power Board: PC Board T2, 7000 MKI Issue 1, REV 1 Here is a list of the chips: Philips 5349 MOC3083 MJE13005F JC448 L78L05 1N4742 MPSA42 Mystery 7MK2-T142 (looks like a quad opamp?) The Zeners 1N4742 look to have been over heated as they are no longer orange and black but grey silver. I'm going to try searching for data sheets. I am not here to bash anyone or any thing. Just documenting what I find and how to go about fixing something that might be of help to others in the same situation. Anyone with experience with these units I would appreciate some assistance and guidance.
Thanks in advance.
I have some Pics and I post as I can get them out of the camera, alsways a challenge. iPhone pics while convenient are typically blurred for some reason. Here are pics of the unit.
Front:
Top down view:
Board view:
Board back view:
The back of this board had crap all over it. I wiped it clean with ISO-OH. It cleaned up nice and shiny while the wipes were brown. Smoke from something that burned or was it Tars from being in a smoke filled room? Doing some basic measurement with the board removed: Upper center board: Two 5W Cement resistors 62K and 39K measured abnout 1 ohm. The diodes and the resistors didn't read correctly.
The diodes read in both directions, .547 on the resistor check and 1.08 the incorrect direction. Pulled one leg up on each, and the resistors measured properly. Do did the diodes. I replaced the diodes just in case, didn't need to because the new one measured the same when installed. Next came the the two watt resistors to the center right. These were 330ohm and 560 ohm wired in series. 330 ohm were find but when checking 560 ohm they were both open.
Pulled a leg each with the same result, open. Removed them and meausred them. 560 Ohm each. WTF over? Turned my meter off and on meausred 560 ohm. Decided to replace them with 600 ohm 2 watt dale wire wound that I had on hand. Reinstalled board, same result...still have the burning 100 watt bulb. Found some of the problem by letting the unit warm up. It appears the MJE13005F and the JC448 are the problems as they are both on a heat sink. at about 15 mins at 60V with the 100 watt bulb...the heat sink burns to the touch.
It might also explain why have have AC on both sides of F401 fuse when the fuse is NOT installed. I don't know why they fried though and that worries me. Wondering what else they take with them? 1N4742 zeeners show signs of heat problem. More pics soon. Update on Data sheets: Philips 5249 is a BT136 Triac, 600V 4 Amp. JC448 my bad is a MJE13003 or 2SA1709/2SC4489 NPN my guess is the MJE13003 and/or 2SC4489 NPNHV Switch. 700Vdc peak, from Ic 1.5 Acd, Ib .75 Adc, Ie 2.25 Adc continuous. MOC 3083 is an opto Isolator powered by 240 VAC. 4n35 are opto couplers w/input to output peak @ 3.55KV. The specs on these are pretty beefy though. These things are pretty beefy, I hope it isn't that quad opamp that fried.... Light of my life:
Voltage Reading:
Focused Board Closeup:
Update, Well as long as I'm here and going to pull the board again might as well shot gun it. First though I'll pull the mystery chip...just to be sure and then see if it still pulls current. That will rule out that part of the PS I'm thinking. Then, I'll pull the SS units and go from there. NOTE: When you link pics from the Gallery here for some reason I don't have ability to zoom in. : ( I was wrong again on some of the parts. Some of the parts I couldn't find readily but will substitue some of them. For some of the parts I wonder if it hasn't been already replaced with a lower speced part before I got it. I don't know. As I don't have a resource.
Let me see if I can find a schematic for you. Otherwise Richard has access if I can't find it.
What is the history of it? If it was returned to Monster it would have been replaced if defective.
for general troubleshooting-
1) The board you are looking at has the main surge stuff and some of the "smarts".
2) with the board out check for shorts on the AC in and the AC outs to confirm the short is on that board.
3) Your testing suggest the first thing to look at is the "T-2" circuit. It prevents the unit from powering up if the voltage is below or above normal. It controls the big relay that is at the input side of the circuit. Its possible that the power supply for the T-2 protection is shorted. Its supposed to withstand 400 VAC continuous but things happen. I believe its direct off line in that box to its all hazardous to work on live.
What is the history of it? If it was returned to Monster it would have been replaced if defective.
for general troubleshooting-
1) The board you are looking at has the main surge stuff and some of the "smarts".
2) with the board out check for shorts on the AC in and the AC outs to confirm the short is on that board.
3) Your testing suggest the first thing to look at is the "T-2" circuit. It prevents the unit from powering up if the voltage is below or above normal. It controls the big relay that is at the input side of the circuit. Its possible that the power supply for the T-2 protection is shorted. Its supposed to withstand 400 VAC continuous but things happen. I believe its direct off line in that box to its all hazardous to work on live.
Board T2 Data Gathering
Richard, Demian:
Richard -
I can't get that far because the board T2 shorts the fuse with no connections to it.
Wiring: I have know way of knowing how the input transformer should be wired. I will assume it was wired correctly...that is: from the left to the right on the T2 board layout J404 (Black Spade lug and terminal) to J115 Filter board - 100 ohm MOV416 - Open BT136 - n/a J406 (White Spade lug and terminal) to J116 Filter board dot - 100 ohm
White to Black measures 100 ohm across the wires on the filter board.
The Connections J402 to the transformer there via block J110 on filter board. L - Black to L Board w/dot N - White to N board. Measuring between these to terminals is 1.1 ohms.
Main power to board. From Plug to board terminals. Brn-breaker-Blk-L terminal Blu - N terminal Grn/Yel - G terminal
NOTE: Bulb Illuminates at 1/4 power, bright light = current draw.
Demian:
History - fleabay purchase doesn't work. 1. I assumed the T2 board was the main power supply with some smarts. 2. Looking for AC but instant flash of fuse. 3. Looked at T2 board and circuit.
Trying to figure out what is drawing the current. the 13005 and 13003 get hotter then hell on the heat sink at 60 VAC.
Measured all the MOVs. The only MOV to test open is MOV416 by the BT136.
All other MOVS have moving resistance which increases as meausred.
However, Systematic Electronic Troubleshooting: A Flowchart Approach, James Perozzo, 1989, says MOV should all test open. However I'm not sure of if they will in the circuit?
All the MOVs and Thermal Fuses test identical:
MOV401,402,403,404 (S20K140) test to 5Meg Ohms rising. MOV405, 406, 407, 408 (241K20D) test to 15Meg ohm rising. TF401, 2, 3, 4 test .3 ohms. MOV1, 2, 3, 4, 5, 6: 1/3 test from 1M ohm resting at 8M ohm. 2/3 test from 1M ohm resting at 7.8M ohm 3/3 test from 1M ohm resting at 8.5M ohm.
MOV416 Test Open. S20K275.
KEF or MJE 13005F test:
Vdc (000 = 0.000 Vdc)
Diode Check (blk & red)
...E.....C.....B
..000.........blk
....... 002...blk
..002..blk.......
.......blk....001
..blk..002......
..blk.........000
MJE 13003
Vdc (201 = .203 Vdc)
Diode Check (blk & red)
...E.....C.....B
..203..........blk
.......201....blk
..003..blk.......
.......blk....198
..blk..002......
..blk.........197
L401 wht, blu, red all test .3 ohm.
C401 0.1K 1.54uf...8Mohm stop
C402 1.0K 1.54uf...8Mohm stop
I"m wonderin about the caps:
C1, 100uf/100V 1.25 K ohm
C2 100uf/16V 2.1K ohm
C3 10uf/25V 4.5 K ohm
C4? 1uf/30V 213 Ohm
I"m wonderin about the caps: C1, 100uf/100V 1.25 K ohm C2 100uf/16V 2.1K ohm C3 10uf/25V 4.5 K ohm C4? 1uf/30V 213 Ohm
For now that's what I've found. It's late and I research the measurements later.
Thanks for stopping by, any ideas will be appreciated.
Richard, Demian:
Richard -
I can't get that far because the board T2 shorts the fuse with no connections to it.
Wiring: I have know way of knowing how the input transformer should be wired. I will assume it was wired correctly...that is: from the left to the right on the T2 board layout J404 (Black Spade lug and terminal) to J115 Filter board - 100 ohm MOV416 - Open BT136 - n/a J406 (White Spade lug and terminal) to J116 Filter board dot - 100 ohm
White to Black measures 100 ohm across the wires on the filter board.
The Connections J402 to the transformer there via block J110 on filter board. L - Black to L Board w/dot N - White to N board. Measuring between these to terminals is 1.1 ohms.
Main power to board. From Plug to board terminals. Brn-breaker-Blk-L terminal Blu - N terminal Grn/Yel - G terminal
NOTE: Bulb Illuminates at 1/4 power, bright light = current draw.
Demian:
History - fleabay purchase doesn't work. 1. I assumed the T2 board was the main power supply with some smarts. 2. Looking for AC but instant flash of fuse. 3. Looked at T2 board and circuit.
Trying to figure out what is drawing the current. the 13005 and 13003 get hotter then hell on the heat sink at 60 VAC.
Measured all the MOVs. The only MOV to test open is MOV416 by the BT136.
All other MOVS have moving resistance which increases as meausred.
However, Systematic Electronic Troubleshooting: A Flowchart Approach, James Perozzo, 1989, says MOV should all test open. However I'm not sure of if they will in the circuit?
All the MOVs and Thermal Fuses test identical:
MOV401,402,403,404 (S20K140) test to 5Meg Ohms rising. MOV405, 406, 407, 408 (241K20D) test to 15Meg ohm rising. TF401, 2, 3, 4 test .3 ohms. MOV1, 2, 3, 4, 5, 6: 1/3 test from 1M ohm resting at 8M ohm. 2/3 test from 1M ohm resting at 7.8M ohm 3/3 test from 1M ohm resting at 8.5M ohm.
MOV416 Test Open. S20K275.
KEF or MJE 13005F test:
Vdc (000 = 0.000 Vdc)
Diode Check (blk & red)
...E.....C.....B
..000.........blk
....... 002...blk
..002..blk.......
.......blk....001
..blk..002......
..blk.........000
MJE 13003
Vdc (201 = .203 Vdc)
Diode Check (blk & red)
...E.....C.....B
..203..........blk
.......201....blk
..003..blk.......
.......blk....198
..blk..002......
..blk.........197
L401 wht, blu, red all test .3 ohm.
C401 0.1K 1.54uf...8Mohm stop
C402 1.0K 1.54uf...8Mohm stop
I"m wonderin about the caps:
C1, 100uf/100V 1.25 K ohm
C2 100uf/16V 2.1K ohm
C3 10uf/25V 4.5 K ohm
C4? 1uf/30V 213 Ohm
I"m wonderin about the caps: C1, 100uf/100V 1.25 K ohm C2 100uf/16V 2.1K ohm C3 10uf/25V 4.5 K ohm C4? 1uf/30V 213 Ohm
For now that's what I've found. It's late and I research the measurements later.
Thanks for stopping by, any ideas will be appreciated.
The transformers are after the "T2" board and the main filter board. They can cause confusion because they look like a short at DC.
The instant fuse pop suggests a short at the input of the power supply that runs the T2 and controller board. I would check the filter caps for shorts. The main circuit waits about 5-10 seconds before turning on as part of the main power stability test. The relay is normally open so only the input stuff is powered at turn on.
I won't be able to get a schematic until the middle of next week. Richard may be able to get one sooner from his contact at the assembly shop. I have not had occasion to look at the schematic for 10 years so my memory is very fuzzy on details.
The instant fuse pop suggests a short at the input of the power supply that runs the T2 and controller board. I would check the filter caps for shorts. The main circuit waits about 5-10 seconds before turning on as part of the main power stability test. The relay is normally open so only the input stuff is powered at turn on.
I won't be able to get a schematic until the middle of next week. Richard may be able to get one sooner from his contact at the assembly shop. I have not had occasion to look at the schematic for 10 years so my memory is very fuzzy on details.
Pulled out the filter board.
Measuring it is kinda strange. from what I've observed is nothing is fixed. So if your measuring resistances of caps, MOVs, coils and diodes they start somewhere and goes up or down.
Lytics measure as follows (Blu ELNA 85 C):
C 123 4700uf 25V from .445 MOhms to 14.7MOhms
C 126 470uf 25V from 2.9 MOhms to 2.75 MOhms
C 127 4700uf 25V from 1.185 MOhms to 6.84 MOhms
Films (WIMA) measure:
C124 .1uf/63V 1.156 MOhms
C125 .1uf/63V 2.89 MOhms
Balanced ISO Xformers
Measure from 1 ohm to 2 ohms.
from YEL to BRN 2 ohms
from RED to BLU 1.9 ohms
From RED or BLU to GND 1 ohm
The MOVs in the circuit seem to test okay.\ That is they start around 1 MOhm and peak around 5 MOhm or 6 MOhm. Their fuses are at .2 Ohms ea. Havent tested the L7805 yet but it looks suspect. The rubber is pulled from the heat sink.
The PWR Xfrmr seems okay as it measures
0 to 120V tap 106 Ohms
The Secondaries measure:
10.5V at 1.3 Ohm
9V at 4.7 Ohm
16V at 3.0 Ohm
I'll try to rig up something... Was going to try and rig up an octopus rig. Thinking I should try and rig up something for the Power xfrmr on this filter board and see how it measures up in circuit. And then try to guestimate test points on it and their voltages.
I sure wish some schematic or troubleshooting info would show up it would point me in the right direction.
Measuring it is kinda strange. from what I've observed is nothing is fixed. So if your measuring resistances of caps, MOVs, coils and diodes they start somewhere and goes up or down.
Lytics measure as follows (Blu ELNA 85 C):
C 123 4700uf 25V from .445 MOhms to 14.7MOhms
C 126 470uf 25V from 2.9 MOhms to 2.75 MOhms
C 127 4700uf 25V from 1.185 MOhms to 6.84 MOhms
Films (WIMA) measure:
C124 .1uf/63V 1.156 MOhms
C125 .1uf/63V 2.89 MOhms
Balanced ISO Xformers
Measure from 1 ohm to 2 ohms.
from YEL to BRN 2 ohms
from RED to BLU 1.9 ohms
From RED or BLU to GND 1 ohm
The MOVs in the circuit seem to test okay.\ That is they start around 1 MOhm and peak around 5 MOhm or 6 MOhm. Their fuses are at .2 Ohms ea. Havent tested the L7805 yet but it looks suspect. The rubber is pulled from the heat sink.
The PWR Xfrmr seems okay as it measures
0 to 120V tap 106 Ohms
The Secondaries measure:
10.5V at 1.3 Ohm
9V at 4.7 Ohm
16V at 3.0 Ohm
I'll try to rig up something... Was going to try and rig up an octopus rig. Thinking I should try and rig up something for the Power xfrmr on this filter board and see how it measures up in circuit. And then try to guestimate test points on it and their voltages.
I sure wish some schematic or troubleshooting info would show up it would point me in the right direction.
Shame on me. Looks can be deceiving. Made a little test rig, worked through the power xfrmr. I think it's fine along with most all the associated components. Thinking the ripple on the DC is too high at 10 percent. Vin for the L7805 is 14.04 Vdc with 1.4 Vac ripple on it. Vout for it is 4.96 Vdc.
Using the test rig and lowering the Vac for the board to about 104 Vac adjusts the voltage to 11.96 Vdc to check the relays. The Filter board is layed out simply and with a little time its pretty simple to figure out. I jumpered one of the diodes on the ground side on one end and to the common ground side of the relay connection terminal. Then hooked to the 14 Vdc (now 12 Vdc) terminal connection that goes to the brains board next to the face plate and the opposite end I used to actuate the relays.
I can now go back to the T2 board and test those relays. I know at least something on the T2 board is shorted out. I'm fixing to replace the 'lytics on the filter board with some higher temp chem cons. And measure again.
Film at 10 O'clock.
Nuts,
Well the LM339, I guess is some other chip. Or is the LM399 in the diagram one half of the real 28 pin chip? The chip in the unit is "7kM2-T142".
The schematic shows U401A, U401B, U401C, U401D, which look to be op amps with pins 1 - 14 used. I've looked for a data sheet but they only show standard op amps with buffers attached to them.
Different then this unit. I put the chip back in and figured I'd measure J402 and see if I got any voltage. No voltage to 60 Vac. But I did start seeing sparks fly from the HV switch chips. the MJE's. Not a good sign. I guess it would correspond to U407 But instead of a TL431 with REF AK they are the MJE pair.
OK
Yes, I"ve been testing on the variac with the board disconnected on the bench.
Pic coming next.
Pics:
Board under test, 60 Vac in, limited to 15.Vac at input.
Just the board layed out:
Richard,
The heat sink will get hotter than hell. Its there next to the two cement resistors. Those are the two MJEs.
None of the 'Lytics get warm. The L401, Red Wht Blu wired RF input choke starts smelling up and get slightly warm to the touch. the U406 the MOC3083 also get s warm to the touch. Not much else does. It will start pulling current around 30 Vac. If brought up quickly, then 25 Vac the bulb comes on. If brought up slowly, then 30 - 35 Vac, brings the bulb on. The soft current limiter is my friend.
Richard, Demian,
Is the 28 pin chip and eprom chip?
something like this:
ATMEGA168 Datasheet pdf - 16K Byte self-programming Flash Program Memory, 1K Byte SRAM, 512 Bytes EEPROM, 8 Channel 10-bit A/D-converter(TQFP/MLF). debugWIRE On-chip Debug System. Up to 24 MIPS throughput at 24 MHz. 1.8 - 5.5 Volt Operation (ATmega16
or similar to this:
The RRRRRRRRRRBBA, a $3 Arduino : The ATMEGA chip IS a cheap microcontroller!
or this:
Arduino - PinMapping168
I hope it's not fried. The good news is I got her up and running...so far. The T2 board has no current draw as I tested it before reinstalling. The buttons don't function now, but then I don't know if they functioned before. The Front panel display doesn't work. But the lower half does does show the splash screen when voltage of about 80V is applied. For about 1 second is displays "Monster HTPS 7000".
Not sure what is going on with it. I'm thinking it it came in for service somewhere and then someone spilled a coke or a coffee in it. With nothing connected to the unit it is pulling 120 Volts about 1 amp 85 - 90 Volts about 1/2 amp There are also open grounds on the first three of the first four outlets. Not sure how that happens because all four share the same earth gound wire and lug. Not sure if the front panel display works on 12 Vdc or 5 Vdc and where the supply chip is located.
Demian & Richard,
I appreciate the assistance you've given me in getting this pretty nice piece of gear operational. Maybe you can suggest where to look once the checks are complete and the main relays turn on. Should this filter be pulling .8 to .9 amps with nothing connected to it?
I can't see the main T2 relays pulling the current. If they did, then when the High Power relays switched on they also would pull the current down, but do not. So my next question is with the isolation transformers. But why whould they be pulling current with nothing attached to them?
A summary of the replacement parts is included here: MJE13005F replaced with MJE13005, non isolated package TO-220. MJE13003 replaced with MJE 13002, 100V lower max rating than 003. 100uf/100V 85C cap with 220uf/100V 105C cap 100uf/16V 85Ccap with 120uf/62V 105C cap 10uf/25V 85C cap replaced with 10uf/25V 105 C cap 1uf/50V cap replaced with 1uf50V 105 cap 2, 12V zeners replaced 2 1n4007 diodes replaced
On the Filter board I replaced the main filter caps with same value 105C cap and replaced the 470uf/25V cap with a larger 680uf/35V 105C cap.
Now on to the control and display boards.
I removed them, then spent a lot of time cleaning them with high purity isopropal. wiped down first with 99 percent and kimwipes a few times then washed with spray 70 percent. Blown dry. Allowed to dry in the in the hot summer sun. I temp wired it up and set it on top of the chassis. To get the full display to work I was testing the EPROM chips leads using my multimeter. Connected ground to the 5 VDC ground pin 3 of the J208 connection and then testing the EPROM voltages on U202 and U205. These were pins 1, 14, 15, 28, 8, 19, 20.
Then the display started to come alive. Working around the pins then working the switch buttons. Before I reinstall the display and control boards I'll Deoxi and lube the switches, prelace the electrlytics on the boards and replace the zeners on the board. I"ll test it again before reinstalling it. It will be more difficult to install than remove with the rest of the boards installed in the chassis. I'll uninstall the filter board again to find the open grounds outlets 1 - 3. Then put it all back together, test again before seeing how it works in my system.
I"ve got pics of most things that I've done and will post them here and in my gallery as the film is developed. : ) The HTPS seems to pull a lot of current with nothing attached. This is at 120 line voltage.
It also gets hot. On the T2 board, one of the design issues I see is that the main filter cap is right next to the heat sink of the High Power Switching Resistors. This alone should be the cause of numerous failures.
I've replaced this filter with higher temp 105C cap. It still gets warm. I've pulled the T2 board out again and I will relocate the filter farther away and mount is on a smaller board. There is a large ground plane on the back side of the board to which I can mount the Cap's negative lead. The cap will end up being parallel with the T2 board with the rubber towards the heat sink and be about 1/2 - 3/4 inch away. It might be better to use an axial cap as opposed to a radial cap.
Next up is replacing a few zener diodes that were the wrong value I put in.
Finally, as Richard suggested, I try pulling banks of MOVs and see if there is any affect on current usage. NOTE, these are a real PITA to remove as they are fairly large, act as heat sinks when desoldering, especially being no lead soldered in to begin with.
Even with my Weller 80 watt desolder iron, set at over 820F it is hard to get the solder to flow and suck it out. I can set at higher temp but it will start pulling up the trace pads.
Don't get me wrong it is a nice piece of gear of consumer electronics. As a dual sided board and I would have liked the MOV and some other pads to have been full through hole and heavier duty pads...it would make maintenance a lot simpler.
Now I'm wondering if I can mod the solder station I have to help it use more current when it needs it. I can tell you one thing, I've learned a lot about AC gear working on this. It is really strange working on it and measuring it, a lot doesn't make sense if your used to working on "normal" gear. Also, you find the limit of your tools, what they can and cannot do in certain circumstances and you learn that you need some other tools and the limits the manufactures designed them...or perhaps I'm using them beyond their design limits.
So, what do you do when you reach those design limits?
Do It Yourself, what we all do.
In my case I've been limited by the lack of choices for the Weller rework station that I own. Its the WRS 3000. When it works, it works really great. When it doesn't it will $10 and $20 you to death. Also when working with mid to large size through hole work or Tube amp work you need almost hourly maintenance on it.
Fast forward, tring to desolder the big MOVs...can't be done with any of the stock tips. I tried and pulled up three traces.
The largest tip Weller offers is the DS114 and it is too large with an O.D. of .125 inch. The DS113 is too small, because they have a smaller tube inside which won't enable them to go down to the trace on a lead of .040. The next largest tip is the DS111.
The package says its size is .090 inch. I have a few that look a bit larger so I measured them and they are larger with their O.D. .107 inch. I drill the little tube out and end up with a hole sized about .055 inch. Don't forget we want air space around the lead to suck out the solder.
How'd it work in practice?
Great, I'll pulled out the next 5 MOVs with out an issue in about 15 mins.
Now I've got 10 MOVs out and powered it up between and after. Neither made a difference with the unit's current draw about .82 amps with nothing attached to it.
I'll pull up the next four MOVs and test again.
I don't think it will make any difference, but ya never know.
At least this way I'll know for certain, as Demian mentioned MOVs typically don't live in the mid space they either work or don't.
However reports from some tube amp guys say sometimes they do live in the middle zone and people don't realize why the tone of their amps suck...until the MOV is replaced and the tone returns.
That is a story for another day.
Thanks for the bandwidth. Pics tomorrow, when developed unless I used my Polaroid Land camera.
Using the test rig and lowering the Vac for the board to about 104 Vac adjusts the voltage to 11.96 Vdc to check the relays. The Filter board is layed out simply and with a little time its pretty simple to figure out. I jumpered one of the diodes on the ground side on one end and to the common ground side of the relay connection terminal. Then hooked to the 14 Vdc (now 12 Vdc) terminal connection that goes to the brains board next to the face plate and the opposite end I used to actuate the relays.
I can now go back to the T2 board and test those relays. I know at least something on the T2 board is shorted out. I'm fixing to replace the 'lytics on the filter board with some higher temp chem cons. And measure again.
Film at 10 O'clock.
Nuts,
Well the LM339, I guess is some other chip. Or is the LM399 in the diagram one half of the real 28 pin chip? The chip in the unit is "7kM2-T142".
The schematic shows U401A, U401B, U401C, U401D, which look to be op amps with pins 1 - 14 used. I've looked for a data sheet but they only show standard op amps with buffers attached to them.
Different then this unit. I put the chip back in and figured I'd measure J402 and see if I got any voltage. No voltage to 60 Vac. But I did start seeing sparks fly from the HV switch chips. the MJE's. Not a good sign. I guess it would correspond to U407 But instead of a TL431 with REF AK they are the MJE pair.
OK
Yes, I"ve been testing on the variac with the board disconnected on the bench.
Pic coming next.
Pics:
Board under test, 60 Vac in, limited to 15.Vac at input.
An externally hosted image should be here but it was not working when we last tested it.
Just the board layed out:
An externally hosted image should be here but it was not working when we last tested it.
Richard,
The heat sink will get hotter than hell. Its there next to the two cement resistors. Those are the two MJEs.
None of the 'Lytics get warm. The L401, Red Wht Blu wired RF input choke starts smelling up and get slightly warm to the touch. the U406 the MOC3083 also get s warm to the touch. Not much else does. It will start pulling current around 30 Vac. If brought up quickly, then 25 Vac the bulb comes on. If brought up slowly, then 30 - 35 Vac, brings the bulb on. The soft current limiter is my friend.
Richard, Demian,
Is the 28 pin chip and eprom chip?
something like this:
ATMEGA168 Datasheet pdf - 16K Byte self-programming Flash Program Memory, 1K Byte SRAM, 512 Bytes EEPROM, 8 Channel 10-bit A/D-converter(TQFP/MLF). debugWIRE On-chip Debug System. Up to 24 MIPS throughput at 24 MHz. 1.8 - 5.5 Volt Operation (ATmega16
or similar to this:
The RRRRRRRRRRBBA, a $3 Arduino : The ATMEGA chip IS a cheap microcontroller!
or this:
Arduino - PinMapping168
I hope it's not fried. The good news is I got her up and running...so far. The T2 board has no current draw as I tested it before reinstalling. The buttons don't function now, but then I don't know if they functioned before. The Front panel display doesn't work. But the lower half does does show the splash screen when voltage of about 80V is applied. For about 1 second is displays "Monster HTPS 7000".
Not sure what is going on with it. I'm thinking it it came in for service somewhere and then someone spilled a coke or a coffee in it. With nothing connected to the unit it is pulling 120 Volts about 1 amp 85 - 90 Volts about 1/2 amp There are also open grounds on the first three of the first four outlets. Not sure how that happens because all four share the same earth gound wire and lug. Not sure if the front panel display works on 12 Vdc or 5 Vdc and where the supply chip is located.
Demian & Richard,
I appreciate the assistance you've given me in getting this pretty nice piece of gear operational. Maybe you can suggest where to look once the checks are complete and the main relays turn on. Should this filter be pulling .8 to .9 amps with nothing connected to it?
I can't see the main T2 relays pulling the current. If they did, then when the High Power relays switched on they also would pull the current down, but do not. So my next question is with the isolation transformers. But why whould they be pulling current with nothing attached to them?
A summary of the replacement parts is included here: MJE13005F replaced with MJE13005, non isolated package TO-220. MJE13003 replaced with MJE 13002, 100V lower max rating than 003. 100uf/100V 85C cap with 220uf/100V 105C cap 100uf/16V 85Ccap with 120uf/62V 105C cap 10uf/25V 85C cap replaced with 10uf/25V 105 C cap 1uf/50V cap replaced with 1uf50V 105 cap 2, 12V zeners replaced 2 1n4007 diodes replaced
On the Filter board I replaced the main filter caps with same value 105C cap and replaced the 470uf/25V cap with a larger 680uf/35V 105C cap.
Now on to the control and display boards.
I removed them, then spent a lot of time cleaning them with high purity isopropal. wiped down first with 99 percent and kimwipes a few times then washed with spray 70 percent. Blown dry. Allowed to dry in the in the hot summer sun. I temp wired it up and set it on top of the chassis. To get the full display to work I was testing the EPROM chips leads using my multimeter. Connected ground to the 5 VDC ground pin 3 of the J208 connection and then testing the EPROM voltages on U202 and U205. These were pins 1, 14, 15, 28, 8, 19, 20.
Then the display started to come alive. Working around the pins then working the switch buttons. Before I reinstall the display and control boards I'll Deoxi and lube the switches, prelace the electrlytics on the boards and replace the zeners on the board. I"ll test it again before reinstalling it. It will be more difficult to install than remove with the rest of the boards installed in the chassis. I'll uninstall the filter board again to find the open grounds outlets 1 - 3. Then put it all back together, test again before seeing how it works in my system.
I"ve got pics of most things that I've done and will post them here and in my gallery as the film is developed. : ) The HTPS seems to pull a lot of current with nothing attached. This is at 120 line voltage.
It also gets hot. On the T2 board, one of the design issues I see is that the main filter cap is right next to the heat sink of the High Power Switching Resistors. This alone should be the cause of numerous failures.
I've replaced this filter with higher temp 105C cap. It still gets warm. I've pulled the T2 board out again and I will relocate the filter farther away and mount is on a smaller board. There is a large ground plane on the back side of the board to which I can mount the Cap's negative lead. The cap will end up being parallel with the T2 board with the rubber towards the heat sink and be about 1/2 - 3/4 inch away. It might be better to use an axial cap as opposed to a radial cap.
Next up is replacing a few zener diodes that were the wrong value I put in.
Finally, as Richard suggested, I try pulling banks of MOVs and see if there is any affect on current usage. NOTE, these are a real PITA to remove as they are fairly large, act as heat sinks when desoldering, especially being no lead soldered in to begin with.
Even with my Weller 80 watt desolder iron, set at over 820F it is hard to get the solder to flow and suck it out. I can set at higher temp but it will start pulling up the trace pads.
Don't get me wrong it is a nice piece of gear of consumer electronics. As a dual sided board and I would have liked the MOV and some other pads to have been full through hole and heavier duty pads...it would make maintenance a lot simpler.
Now I'm wondering if I can mod the solder station I have to help it use more current when it needs it. I can tell you one thing, I've learned a lot about AC gear working on this. It is really strange working on it and measuring it, a lot doesn't make sense if your used to working on "normal" gear. Also, you find the limit of your tools, what they can and cannot do in certain circumstances and you learn that you need some other tools and the limits the manufactures designed them...or perhaps I'm using them beyond their design limits.
So, what do you do when you reach those design limits?
Do It Yourself, what we all do.
In my case I've been limited by the lack of choices for the Weller rework station that I own. Its the WRS 3000. When it works, it works really great. When it doesn't it will $10 and $20 you to death. Also when working with mid to large size through hole work or Tube amp work you need almost hourly maintenance on it.
Fast forward, tring to desolder the big MOVs...can't be done with any of the stock tips. I tried and pulled up three traces.
The largest tip Weller offers is the DS114 and it is too large with an O.D. of .125 inch. The DS113 is too small, because they have a smaller tube inside which won't enable them to go down to the trace on a lead of .040. The next largest tip is the DS111.
The package says its size is .090 inch. I have a few that look a bit larger so I measured them and they are larger with their O.D. .107 inch. I drill the little tube out and end up with a hole sized about .055 inch. Don't forget we want air space around the lead to suck out the solder.
How'd it work in practice?
Great, I'll pulled out the next 5 MOVs with out an issue in about 15 mins.
Now I've got 10 MOVs out and powered it up between and after. Neither made a difference with the unit's current draw about .82 amps with nothing attached to it.
I'll pull up the next four MOVs and test again.
I don't think it will make any difference, but ya never know.
At least this way I'll know for certain, as Demian mentioned MOVs typically don't live in the mid space they either work or don't.
However reports from some tube amp guys say sometimes they do live in the middle zone and people don't realize why the tone of their amps suck...until the MOV is replaced and the tone returns.
That is a story for another day.
Thanks for the bandwidth. Pics tomorrow, when developed unless I used my Polaroid Land camera.
Sync- You have the schematics now.
First, on sheet 7 is the "T2" circuit that checks for valid AC power levels. If that does not see a voltage below 130V AC and above about 70V AC the relay that turns the whole thing on will not energize. Its the starting point. Its very possible that the shunt regulator or the LM339 could have failed. Or there could be an open circuit on the board or on a connection.
Let us know what you find.
First, on sheet 7 is the "T2" circuit that checks for valid AC power levels. If that does not see a voltage below 130V AC and above about 70V AC the relay that turns the whole thing on will not energize. Its the starting point. Its very possible that the shunt regulator or the LM339 could have failed. Or there could be an open circuit on the board or on a connection.
Let us know what you find.
I have studied the T2 sheet. The LM399 could have failed but I removed it before apply the next series of tests. Between 30 volts and 60 volts just the T2 board goes from .2 amps to .6 amps current draw with a 100 watt bulb in series glowing brightly.
The cucurrent starts coming on strong around 25 - 35 volts. Perzzo classifies this short as a "psuedo-zener short", that is when you start applying power, it reaches a point where it starts sucking power or turns on like a zener would. However, it will stabilize at 30 Volts and current will slowly decrease.
Also between 30 volts and 60 volts I've let some of the smoke out of the MJE13005 MJE13003 combo. More from the smaller one than the larger one. I don't just want to pull and replace them and have something down- stream take the new chips out. Also checking the U406 (MOC3083) with the diode checker has fwd and revers voltage on pins 1 and 2. F 1.025, R 1.014. It was warm. The Rf input choke was also warm. The MJE s are pretty tough units rated at 40 watts max. Wonder why they are switching their lives away? I can't find the short. If something is open, then it wouldn't pull current.
The cucurrent starts coming on strong around 25 - 35 volts. Perzzo classifies this short as a "psuedo-zener short", that is when you start applying power, it reaches a point where it starts sucking power or turns on like a zener would. However, it will stabilize at 30 Volts and current will slowly decrease.
Also between 30 volts and 60 volts I've let some of the smoke out of the MJE13005 MJE13003 combo. More from the smaller one than the larger one. I don't just want to pull and replace them and have something down- stream take the new chips out. Also checking the U406 (MOC3083) with the diode checker has fwd and revers voltage on pins 1 and 2. F 1.025, R 1.014. It was warm. The Rf input choke was also warm. The MJE s are pretty tough units rated at 40 watts max. Wonder why they are switching their lives away? I can't find the short. If something is open, then it wouldn't pull current.
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There are three banks of MOV. Find them... remove the thermal tape around each bank, if you have to. Then, one at a time, disable a bank of MOV and recheck for current draw (MOV are from L-N and L-L and L-G.) Do for each bank, one bank at a time until the bad bank is found. The MOV tend to short when a Very high voltage transient hits them.... you might have a partial short in one of the MOV's in one of the banks/groups (some low resistance residual).
Are there any caps that get warm on the input/protection pcb?
THx-RNMarsh
Sync-
Back to sheet 4, the T2 board. Lets work through that first. Blown MOVs are unlikely actually. The T2 circuit will prevent most of the causes of blown MOV's and we have not seen a failure of that type on any of the products with T2 yet. The MOV's with either be OK or fried. They don't have a middle state where the breakdown voltage is reduced. The symptoms are more those of a failed supply cap or diode. On the T2 board disconnect J402 that goes to the filter board and J404, J406 so it is the only board in the system. The relay will not turn on like this. Check for shorts and supply voltage to see if you still have the problem. I would then power the relays with a 12V supply and see if a problem surfaces. It is designed to run directly off the line and handle in excess of 400V. (Do not touch when energized!) There is a triac, Q405, that powers the control board (I think).
If the LM339 is out the unit cannot start. >.6A into an MOV will get you a lot of smoke pretty fast. The continuous dissipation is closer to .5W so .6X30V is a lot of power.
Can you post a photo of the MJE's so I can see where they are?
Sorry for the less than linear troubleshooting post. I'm still thinking the problem through.
Back to sheet 4, the T2 board. Lets work through that first. Blown MOVs are unlikely actually. The T2 circuit will prevent most of the causes of blown MOV's and we have not seen a failure of that type on any of the products with T2 yet. The MOV's with either be OK or fried. They don't have a middle state where the breakdown voltage is reduced. The symptoms are more those of a failed supply cap or diode. On the T2 board disconnect J402 that goes to the filter board and J404, J406 so it is the only board in the system. The relay will not turn on like this. Check for shorts and supply voltage to see if you still have the problem. I would then power the relays with a 12V supply and see if a problem surfaces. It is designed to run directly off the line and handle in excess of 400V. (Do not touch when energized!) There is a triac, Q405, that powers the control board (I think).
If the LM339 is out the unit cannot start. >.6A into an MOV will get you a lot of smoke pretty fast. The continuous dissipation is closer to .5W so .6X30V is a lot of power.
Can you post a photo of the MJE's so I can see where they are?
Sorry for the less than linear troubleshooting post. I'm still thinking the problem through.
Hi,
Current draw you see is thru the filters and is normal.
Suggestion: You do not have to remove the MOV's to find out if they are a problem or not.... just cut a pcb trace to them will disconnect them.... later put in a jumper wire across the cut pcb gap.
Changing to 105C caps is always a good idea for longer life.
THx-RNMarsh
Current draw you see is thru the filters and is normal.
Suggestion: You do not have to remove the MOV's to find out if they are a problem or not.... just cut a pcb trace to them will disconnect them.... later put in a jumper wire across the cut pcb gap.
Changing to 105C caps is always a good idea for longer life.
THx-RNMarsh
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Thanks Richard,
Now you tell me. I guess there is more than one way to skin the cat.
Hopefully you like pics more than just reading. I figure I'd save more than just a couple of thousand words here:
Parts pulled and replacements Note: The pad on the right where the original MJE was arching. Since I didn't have a replacement I cleaned it as best as I could then I flipped it around at least now the carbon bits are against the heat sink on the opposite pin.
Test w/o MOVs, nothing fancy but it works. All hooked up and the LED and cotrol board on wood for stability and isolation. I think I've almost got it working properly. Just a few more tweaks and we are off and running.
Here the desolder tool with the custom tip. Best thing is it works.
Here are the various tips, from left DS114, DS111, DS112, DS113, DS110,DS111 At over $10 a tip you try not to waste any but want them to work for you. Keep 'em clean and apply solder to protect 'em.
Now you tell me. I guess there is more than one way to skin the cat.
Hopefully you like pics more than just reading. I figure I'd save more than just a couple of thousand words here:
Parts pulled and replacements Note: The pad on the right where the original MJE was arching. Since I didn't have a replacement I cleaned it as best as I could then I flipped it around at least now the carbon bits are against the heat sink on the opposite pin.
Test w/o MOVs, nothing fancy but it works. All hooked up and the LED and cotrol board on wood for stability and isolation. I think I've almost got it working properly. Just a few more tweaks and we are off and running.
Here the desolder tool with the custom tip. Best thing is it works.
Here are the various tips, from left DS114, DS111, DS112, DS113, DS110,DS111 At over $10 a tip you try not to waste any but want them to work for you. Keep 'em clean and apply solder to protect 'em.
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Sync:
I'm trying to find a replacement board for the T2 board you are testing. There is noting on the board or the system that draws power except the relays. The currents you are measuring are going into the caps and pure reactive currents. Once we find a board I will look at it carefully to check where all that power is going. There may be a shorted resistor or something like that in the power supply. Or it could be the power draw of all the relays powered up that the supply is supporting.
If you or anyone comes across "marginal but not cooked" MOV's I want to see them.
I'm trying to find a replacement board for the T2 board you are testing. There is noting on the board or the system that draws power except the relays. The currents you are measuring are going into the caps and pure reactive currents. Once we find a board I will look at it carefully to check where all that power is going. There may be a shorted resistor or something like that in the power supply. Or it could be the power draw of all the relays powered up that the supply is supporting.
If you or anyone comes across "marginal but not cooked" MOV's I want to see them.
T2 Power Board
In testing the board looking and thinking about the current draw I began to wonder about that too, the relays. After a second wipe down of the LED and Control board I think I got it working properly. I noticed the relays were taking a while and some were lengthy. I fooled around, er investigated, with it a bit further and discovered that I could program the order and the timing of the relays turning on. That way I could monitor each progressive turn on.
Now, I've programmed it for a 4 second delay then it turns on the relays from number 01 to number 06 two seconds apart. As screwed up as this thing was and may still be, you guys did a nice job protecting the switch functions, the control units, and the displays. I appreciate the way the T2 board is physically isolated from the other boards with about 1/16 to 1/8 inch of steel between it and the filterboard and isolation transformers behind it.
Back to testing...
The main power relay causes the big current draw. Subsequent relays have no affect on the current draw. That leads me to the next questions. Perhaps it could be a relay problem, the main RF choke, or the isolation transformers. Looking at the isolations windings under the film it looks to darken the copper and filled with dark gray...smoke perhaps? remnants of it burning from a partial winding short from a spill which more than likely caused the other problems.
Once the carbon arching starts it usually keeps eating away at things. Same with the RF input choke. I think there may be a short/arching in each that is just burning away in there. I still smell the RF input choke and it was over heading with the MJE short. With the T2 board cleaned and removed there is an odor from the isolation transformers. I can try to load it up with a big ol 1/2 inch to 3/4 inch industrial drill and see what kind of current it pulls from the unit. I tried it with an electric fan but I guess it won't pull any current.
I appreciate yours and Richards help and suggestions. I'll keep and eye out for those MOVs and see if I can't track some down. Thanks for the offer of a T2 too. the chain of events to
In testing the board looking and thinking about the current draw I began to wonder about that too, the relays. After a second wipe down of the LED and Control board I think I got it working properly. I noticed the relays were taking a while and some were lengthy. I fooled around, er investigated, with it a bit further and discovered that I could program the order and the timing of the relays turning on. That way I could monitor each progressive turn on.
Now, I've programmed it for a 4 second delay then it turns on the relays from number 01 to number 06 two seconds apart. As screwed up as this thing was and may still be, you guys did a nice job protecting the switch functions, the control units, and the displays. I appreciate the way the T2 board is physically isolated from the other boards with about 1/16 to 1/8 inch of steel between it and the filterboard and isolation transformers behind it.
Back to testing...
The main power relay causes the big current draw. Subsequent relays have no affect on the current draw. That leads me to the next questions. Perhaps it could be a relay problem, the main RF choke, or the isolation transformers. Looking at the isolations windings under the film it looks to darken the copper and filled with dark gray...smoke perhaps? remnants of it burning from a partial winding short from a spill which more than likely caused the other problems.
Once the carbon arching starts it usually keeps eating away at things. Same with the RF input choke. I think there may be a short/arching in each that is just burning away in there. I still smell the RF input choke and it was over heading with the MJE short. With the T2 board cleaned and removed there is an odor from the isolation transformers. I can try to load it up with a big ol 1/2 inch to 3/4 inch industrial drill and see what kind of current it pulls from the unit. I tried it with an electric fan but I guess it won't pull any current.
I appreciate yours and Richards help and suggestions. I'll keep and eye out for those MOVs and see if I can't track some down. Thanks for the offer of a T2 too. the chain of events to