Hi
I need some help in troubleshooting this amp. When I first got the amp, channel 1 was working fine but channel 2 has no sound. When I turn on the amp, the green LEDs come on, then after a second the channel 1 relay clicks, the green LED turns off and the red ODEP turns on. But on the second channel, there is no relay click and both the green and red ODEP LEDs are on and there is no sound. After about 30secs the second channel relay clicks on for a split second and turns off. This keeps repeating about every 30 secs. I placed a DMM across the channel 2 speaker terminals. There is positive voltage present, and it keeps going down. When the voltage falls below approx 8volts, the relays clicks on for a split second and when the relay is on, the voltage shoots to approx 80volts. After a split second the relay turns off and the voltage keeps dropping down until it reaches approx 8 volts and the relays turns on again. This keeps repeating constantly. I have checked all the predriver, driver and the power transistors. There is no shorted component. Can someone assist with this. I have downloaded the service manual but the schematics are missing. Pls assist.
Thanks
I need some help in troubleshooting this amp. When I first got the amp, channel 1 was working fine but channel 2 has no sound. When I turn on the amp, the green LEDs come on, then after a second the channel 1 relay clicks, the green LED turns off and the red ODEP turns on. But on the second channel, there is no relay click and both the green and red ODEP LEDs are on and there is no sound. After about 30secs the second channel relay clicks on for a split second and turns off. This keeps repeating about every 30 secs. I placed a DMM across the channel 2 speaker terminals. There is positive voltage present, and it keeps going down. When the voltage falls below approx 8volts, the relays clicks on for a split second and when the relay is on, the voltage shoots to approx 80volts. After a split second the relay turns off and the voltage keeps dropping down until it reaches approx 8 volts and the relays turns on again. This keeps repeating constantly. I have checked all the predriver, driver and the power transistors. There is no shorted component. Can someone assist with this. I have downloaded the service manual but the schematics are missing. Pls assist.
Thanks
If I remember correctly this amp is with voltage doubler and have special circuity which switch it from 90V to 180V.
When there is no need for high voltage output it will stay on 90V power supply, supply caps will be paralleled by circuit control, when there is need for higher voltage, these supply caps will be in series. Once, I repaired that circuit, someone who doesn't know what it does, replaced one of the capacitor with new one and wires and make mistake. These caps (there are 4 of them, 2 in parallel) should have same characteristics and when they are in series connection, they will have same voltage across them, about 90V on each group of caps, so in total power supply will be about 180V.
Because of high current demand from these caps, maybe some of it fails.
Also check on good channel voltages on network resistor N101 and N102, write them and make comparation on bad one, maybe there is failure on them because they loose their value, and result is voltage on red speaker terminal with reference to ground (black speaker terminal). That is also one of failures which I found on macrotech series. With that failure amp will not produce full power, it will clip on one side of the sinus signal. Reason, amp wouldn't have correct mid point, power supply is with only + and - , so amp produce mid point whit it circuity.
I have to look on another computer to find details which I described, that details are for VZ version of the amp.
That repair I done before some 10 years, so have to look for details I downloaded and wrote on the schematics which I downloaded. As I remember there is no exact service manual for download, so I used schematic for amp details from macrotech 2400 and details about VZ switch from some manual.
When there is no need for high voltage output it will stay on 90V power supply, supply caps will be paralleled by circuit control, when there is need for higher voltage, these supply caps will be in series. Once, I repaired that circuit, someone who doesn't know what it does, replaced one of the capacitor with new one and wires and make mistake. These caps (there are 4 of them, 2 in parallel) should have same characteristics and when they are in series connection, they will have same voltage across them, about 90V on each group of caps, so in total power supply will be about 180V.
Because of high current demand from these caps, maybe some of it fails.
Also check on good channel voltages on network resistor N101 and N102, write them and make comparation on bad one, maybe there is failure on them because they loose their value, and result is voltage on red speaker terminal with reference to ground (black speaker terminal). That is also one of failures which I found on macrotech series. With that failure amp will not produce full power, it will clip on one side of the sinus signal. Reason, amp wouldn't have correct mid point, power supply is with only + and - , so amp produce mid point whit it circuity.
I have to look on another computer to find details which I described, that details are for VZ version of the amp.
That repair I done before some 10 years, so have to look for details I downloaded and wrote on the schematics which I downloaded. As I remember there is no exact service manual for download, so I used schematic for amp details from macrotech 2400 and details about VZ switch from some manual.
Carlosraj,
I redraw from the scratch my notes and I give you what is in 3600VZ, but you have to download service manual for Macro-Tech-5000VZ-Service-Manual from crown audio site.
It is made from 3 parts, third part should have schematic for control.
In this part I couldn't find what I have in paper, so tomorrow I will scan that part of schematic and give you on private mail. Meanwhile I lost (damage) USB stick which have this data, so I can't find that in pdf.
I think it is intentional excluded, so I will not show it here.
I redraw from the scratch my notes and I give you what is in 3600VZ, but you have to download service manual for Macro-Tech-5000VZ-Service-Manual from crown audio site.
It is made from 3 parts, third part should have schematic for control.
In this part I couldn't find what I have in paper, so tomorrow I will scan that part of schematic and give you on private mail. Meanwhile I lost (damage) USB stick which have this data, so I can't find that in pdf.
I think it is intentional excluded, so I will not show it here.
Thanks alot Pitbul. Meanwhile this is what happen just 2 days ago. I have missed out some info. Earlier when I brought in this amp, it was ch2 that had a problem. Upon checking predriver transistors C3298B and A1306B on the main board were blown, since I could not get this transistors I replaced them with MJE15033 and MJE15032 and the amp was still giving problems. Then I exchange all the ICs on the back board, I think the VZ control board including the network resistor ICs from channel 1 to channel 2. When I tested without load both channels seem to be OK. I then connected the speakers, plugged in an audio signal and turned on the amp. Both the channels were working fine. The amp was ON for about 5 hrs and then channel 1 started crackling (channel2 was OK) and then a burn smell followed by sparks from the main board. I turned off the amp and checked all the transistors, resistors,diodes on that channel and all seem OK. Then I reconnected the speakers, put in a signal and ON back the amp. I have been testing the amp again from yesterday and both channels are working fine and no problems so far. I suspect some component on the back board(VZ control) might be faulty. I will go thru the notes and schematics you sent and keep you updated. Thanks again for all your assistance.
Carlosraj
,
I have not taken the voltage readings yet, I removed from the board N101,N102,N201 and N202 and took the readings. These are the readings:- N101,N201.
Pin 1-2 = 9.52K (9.09K)
Pin 2 - 3 = 27.31K (22.1K)
Pin 3 - 4 = 19.55K (24.3K)
Pin 4 - 5 = 19.54K (24.3K)
Pin 5 - 6 = 27.3K (22.1K)
Pin 6 - 7 = 9.52K (9.09K)
N102,N202
Pin2 - 3 = 32.67K (33K)
Pin3 - 4 = 2.58K (3.3K)
Pin4 - 5 = 2.78K (3.56K)
Pin5 - 7 = 32.23K (33K)
Pin1 - 5 = 32.27 (33K)
These are the actual readings I got with the components out of board, the readings in brackets are the readings shown on the schematic. There are some difference in readings. Does these matter. I have to print out the schematic with the voltage readings on them, and then I will take the readings.
Thanks
To me, that are OK values.
Carlosraj, please look at the original schematic of the original scheme, as I wrote, 10 years ago I didn't have original schematic, so I made notes on 2400 schematic.
Values for the resistor network
N101
1-2 =9.55k
2-3 =27.4k
3-4 =19.6k
4-5 =19.6k
5-6 =27.4k
5-6 =9.55k
N102
1-5 =33k
5-7 =33k
2-3 =33k
3-4 =2.64k
4-5 =2.85k
So, as I compared your values, they are for sure OK.
Put it back and measure voltages referenced to the speaker ground, that will show if amp is on correct point (+45V and -45V referenced to gnd). Power supply voltages are what is my point.
Other voltages on my notes were my way to seek the fault. After that I made some adjustments and put amp to the correct point. My problem was at N102 resistor network, so I pointed you to check that.
Carlosraj, please look at the original schematic of the original scheme, as I wrote, 10 years ago I didn't have original schematic, so I made notes on 2400 schematic.
Values for the resistor network
N101
1-2 =9.55k
2-3 =27.4k
3-4 =19.6k
4-5 =19.6k
5-6 =27.4k
5-6 =9.55k
N102
1-5 =33k
5-7 =33k
2-3 =33k
3-4 =2.64k
4-5 =2.85k
So, as I compared your values, they are for sure OK.
Put it back and measure voltages referenced to the speaker ground, that will show if amp is on correct point (+45V and -45V referenced to gnd). Power supply voltages are what is my point.
Other voltages on my notes were my way to seek the fault. After that I made some adjustments and put amp to the correct point. My problem was at N102 resistor network, so I pointed you to check that.
Yes the readings I get are approx +47 and -47. I have been testing the amp for the past few days and it seems to be OK. I will get back if any problem arises.
Thanks