@hifiamps
So I did a heat measurement on each of the big caps, and it appears that one of the (4) bigger caps is showing around 89*F, while the others are around 83/84*F. I also measured the temps on the smaller caps next to the big ones and the temp readings on those were higher, one in particular being around 109*F. Perhaps the smaller size caps (which they have 6 of them) could be going bad as well? I only left the amp on maybe a few minutes when I took these readings. I hope that these measurements can tell you something. I haven't measured the pins on P104 connector yet, as I wanted to make certain I was connecting it correctly. So the have 3 pins on P104, so how should I connect my probes to measure the voltage? I think the best thing would be to use the connecting harness for P104 and I could use my alligator clips on the wires from the harness? I'm just assuming that I could measure pin #1 with pin #2? And then switch to pin #3 leaving my probe on pin#2? Thanks again and I can't thank you enough! Hopefully if it is the caps, and I replace them them and it works, then perhaps someone else that may have this issue, can read this thread and fix their amp as well. 🙂
So I did a heat measurement on each of the big caps, and it appears that one of the (4) bigger caps is showing around 89*F, while the others are around 83/84*F. I also measured the temps on the smaller caps next to the big ones and the temp readings on those were higher, one in particular being around 109*F. Perhaps the smaller size caps (which they have 6 of them) could be going bad as well? I only left the amp on maybe a few minutes when I took these readings. I hope that these measurements can tell you something. I haven't measured the pins on P104 connector yet, as I wanted to make certain I was connecting it correctly. So the have 3 pins on P104, so how should I connect my probes to measure the voltage? I think the best thing would be to use the connecting harness for P104 and I could use my alligator clips on the wires from the harness? I'm just assuming that I could measure pin #1 with pin #2? And then switch to pin #3 leaving my probe on pin#2? Thanks again and I can't thank you enough! Hopefully if it is the caps, and I replace them them and it works, then perhaps someone else that may have this issue, can read this thread and fix their amp as well. 🙂
Pin 2 on P104 is ground. Pin1 is the positive rail and pin 3 is the negative. Leave the ground lead of the DMM connected to pin2. Then check pin 1 voltage as it cycles through to standby. Then switch to pin 3 and follow the voltage as it cycles to standby.
Also check the voltages on the P103 VDD pin 3, VSS pin 5 and Vdrive pin 7 with your ground lead of the DMM connected to pin 1. Monitor the voltages again as it runs through the cycle to standby, if possible. Maybe check these voltages first, since the hot cap is here.
The temps don't seem to bad except for the 109 after only a few minutes, and that is probably a bad cap. The amp will detect problems more quickly, since it is monitoring voltages. It's powering down before catastrophic failure.
A recap on the amp would involve changing all of the electrolytic caps, since you would be going to all the trouble of taking the amp out and removing the aluminum plate to gain access, etc. A bad electrolytic cap is likely the problem. I would like to see some data that confirms voltage is off.
Also check the voltages on the P103 VDD pin 3, VSS pin 5 and Vdrive pin 7 with your ground lead of the DMM connected to pin 1. Monitor the voltages again as it runs through the cycle to standby, if possible. Maybe check these voltages first, since the hot cap is here.
The temps don't seem to bad except for the 109 after only a few minutes, and that is probably a bad cap. The amp will detect problems more quickly, since it is monitoring voltages. It's powering down before catastrophic failure.
A recap on the amp would involve changing all of the electrolytic caps, since you would be going to all the trouble of taking the amp out and removing the aluminum plate to gain access, etc. A bad electrolytic cap is likely the problem. I would like to see some data that confirms voltage is off.
OK I'll get those measurements perhaps later tonight or tomorrow and report back with the readings on P104 and P103. Hopefully this will indicate for sure that one or more caps are bad! I'm not certain what brand these caps are, but if I have to take things apart on the module to get to them and then replace them, I don't mind spending a few more bucks to get better caps! Thanks again hifiamps!
I think all the caps are Nippon Chemi-Con. A reputable brand. I haven't seen Icepower use lower grade caps. Here is a chart of top and bottom markings.
1200AS2 buzzing thread with video
1200AS1 buzzing not working thread with video. This post with your problem.
1200AS1 buzzing not working thread with video. This post with your problem.
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@hifiamps
Sorry for the delay! OK, so I measured the voltages from P104 using pin 2 for ground. When the amp first comes on my DMM goes OL then settles to 62.4V on both the positive rail (pin 1) and the same voltage on negative rail (pin 3) When the amp went into standby/protection, the voltage dropped to around 35V on the positive rail, and around 30V on the negative rail. Then when standby kicks off, they both go back to 62.4VDC. I haven't measured the voltages from P103 yet as I can't find the connector for it. Perhaps icepower cheated me by not sending me one..lol.. I can try and use the smaller tips on the probes for my DMM? Just didn't want to touch anything while measuring. Your thoughts please? Thanks again!
Sorry for the delay! OK, so I measured the voltages from P104 using pin 2 for ground. When the amp first comes on my DMM goes OL then settles to 62.4V on both the positive rail (pin 1) and the same voltage on negative rail (pin 3) When the amp went into standby/protection, the voltage dropped to around 35V on the positive rail, and around 30V on the negative rail. Then when standby kicks off, they both go back to 62.4VDC. I haven't measured the voltages from P103 yet as I can't find the connector for it. Perhaps icepower cheated me by not sending me one..lol.. I can try and use the smaller tips on the probes for my DMM? Just didn't want to touch anything while measuring. Your thoughts please? Thanks again!
The voltage is steady on P104 pin 1 and pin 3, without dropoff, then standby clicks in, correct? No problem there.
Just remove a couple of the unused wires from the housing of P101 or P102. Put some shrink tubing around the contact.
Just remove a couple of the unused wires from the housing of P101 or P102. Put some shrink tubing around the contact.
Yes that is correct. The voltage only drops when the standby comes on. So did you need me to get the voltages on P103 when the standby kicks in?
@hifiamps
So I now have the voltages for P103, pin #1 stayed grounded. Turned amp on, waited for it to go in standby. Here are the readings I took when amp switched to standby: Pin#3 dropped to 12.62V, then went back up to 13.70V when standby went off. Pin#5 dropped to negative -12.65V, then went back up to -13.75V when standby went off. Pin#7 dropped to around 17V when standby came on and right away it switched to on and went back to 50.3V, then within a few seconds it switched back to standby and dropped to around 20V. Does this still indicate a bad cap/s? Thanks!
So I now have the voltages for P103, pin #1 stayed grounded. Turned amp on, waited for it to go in standby. Here are the readings I took when amp switched to standby: Pin#3 dropped to 12.62V, then went back up to 13.70V when standby went off. Pin#5 dropped to negative -12.65V, then went back up to -13.75V when standby went off. Pin#7 dropped to around 17V when standby came on and right away it switched to on and went back to 50.3V, then within a few seconds it switched back to standby and dropped to around 20V. Does this still indicate a bad cap/s? Thanks!
Yes that is correct. I'm guessing that the tolerances of caps are around 20%? So I know the uF values should be within these specs, but does that apply to the temps as well? I do know that the smaller caps (8) have a couple that get warmer than the rest, but not sure if that is causing the standby/protection to be erratic? If I have to take the module out, I am assuming that I can detach the bottom part where the transistors are so I can take more photos and also be able to de-solder the caps for replacement.
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I was hoping to see some of the voltages sagging, indicating a problem. The caps getting warm within only a few minutes before standby kicks in is not normal. On my 500ASP, the caps stay near room temperature. Sometimes they glue a cap right on something that does get warm (for some reason), and that might be an explanation for the warm temperature. The most common part failure would be with the electrolytic power supply caps. Replacing all of them will not be very expensive, but time and labor. When you remove the caps, they can be tested. Getting good pictures of the bottom of the PCB would be helpful to others (I haven't found a picture). If you replace the caps and it still doesn't work, that is a definite risk.
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Well I assume that would be all of the voltage measurements for now. I guess now I will take the module out and try to get some photos so perhaps that may be of help. I also read that on another ice amp module they had a smd resistor that had burned out and caused kind of the same issues I am having. Not sure if that is it or not. Anyhow I really appreciate you for assisting me on this adventure..lol I'll try and tear the module down later to get some better photos. Thanks! 🙂
OK, reporting back with some photos of the bottom of the 1200as2 module. Perhaps this may help as I can take some measurements with my DMM if needed.
Those blue sheets are keratherm I think... make sure you use a new set... you'd probably need to keep the case of all diodes and transistors electrically isolated from the chassis.
A bit of a worry is that set of 4 undamaged ones... Are they making good thermal contact with the chassis??
Nice set of photos, thanks for sharing.
A bit of a worry is that set of 4 undamaged ones... Are they making good thermal contact with the chassis??
Nice set of photos, thanks for sharing.
@Extreme_Boky
Hi and thanks for pic compliment! I have taken another photo of the aluminum heat sink that mounts to the bottom of the pcb. Thanks for letting me know what I will need to get (keratherm) in case I do happen to fix the issue. I'm just not certain where I can begin probing?
Hi and thanks for pic compliment! I have taken another photo of the aluminum heat sink that mounts to the bottom of the pcb. Thanks for letting me know what I will need to get (keratherm) in case I do happen to fix the issue. I'm just not certain where I can begin probing?
Ok, thanks for the photo.
I can tell you now that there is NO NEED to use the keratherm.... No need to worry about electrical isolation (which is provided by means of those large white thermal pads). So all good.
Re the issue at hand... I'd use a digital storage oscilloscope, and then capture what happens over the period during which the issue presents itself. That would give me some clue as to what could possibly be the root cause...
I can tell you now that there is NO NEED to use the keratherm.... No need to worry about electrical isolation (which is provided by means of those large white thermal pads). So all good.
Re the issue at hand... I'd use a digital storage oscilloscope, and then capture what happens over the period during which the issue presents itself. That would give me some clue as to what could possibly be the root cause...
To be honest, the only thing I have with an oscilloscope is on a program I purchased a while back called DATS from Parts Express. I never used the oscilloscope on it, as I just measured caps, inductors, and resistors. Do you think something like that would work? Thanks!