|24th May 2014, 06:35 PM||#1|
Troubleshoot HTPS 7000
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.
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
PC Board T2, 7000 MKI Issue 1, REV 1
Here is a list of the chips:
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.
Last edited by SyncTronX; 24th May 2014 at 06:44 PM.
|24th May 2014, 07:29 PM||#2|
Re: Monster HTPS 7000MKII PS
Here are pics of the unit.
Top down 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.
|24th May 2014, 08:30 PM||#3|
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.
|24th May 2014, 11:16 PM||#4|
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
Light of my life:
Focused Board Closeup:
Last edited by SyncTronX; 24th May 2014 at 11:35 PM.
|28th May 2014, 02:27 AM||#5|
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.
Last edited by SyncTronX; 28th May 2014 at 02:32 AM.
|28th May 2014, 03:46 AM||#6|
check to see that input (transformers etc) isnt wired for 230v operation.
next are the many thermal fuses... they blow if there is a shorted cap or an over-voltage surge. Check for short of the mov banks and any caps which may have shorted/partial short.
Last edited by RNMarsh; 28th May 2014 at 03:50 AM.
|29th May 2014, 06:06 AM||#7|
Join Date: Mar 2004
Location: SF Bay Area
Blog Entries: 3
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.
Product Design Services
|30th May 2014, 06:37 AM||#8|
Board T2 Data Gathering
I can't get that far because the board T2 shorts the fuse with
no connections to it.
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.
Blu - N terminal
Grn/Yel - G terminal
NOTE: Bulb Illuminates at 1/4 power, bright light = current draw.
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
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)
Vdc (201 = .203 Vdc)
Diode Check (blk & red)
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
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.
|30th May 2014, 06:58 AM||#9|
Join Date: Mar 2004
Location: SF Bay Area
Blog Entries: 3
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.
Product Design Services
|30th May 2014, 03:01 PM||#10|
Contact: Magnet Technology, Bangkok, Thailand. Mr Sobswad -- get details from Magnet Tech web site. Ask for schematic or repair info.
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