Class D amp issue/need advice

Hi, I assume this is the place to ask for assistance/help with a problem I am having? Not sure if there is another thread that's for the sole purpose of trouble-shooting class d amplifiers?

Anyhow, I have an issue with my Icepower 1200as2 amp module. Just out of the blue it started switching from ON to STANDBY, even when a signal is present. When I assembled this amp together, I wanted (2) LEDS (Blue and Amber) to display when the amp is in the ON mode, then after a few minutes or so with no signal, the amber LED would come on. It had been working fine for a long time, then one day it started. So I unplugged the unit and pulled the top off to see if I could notice anything visually. Nothing stood out. I even disconnected and reconnected the connections that connect to various plug-ins. I then tried it again and it worked for a while, then started doing the same thing. This seems a little crazy to me as I did it once again by unplugging the unit for a day or so, then plugged it back in and it stayed working good for a longer time, but now it's starting to act up again?? I have no idea why! Perhaps someone may know of a solution, as I really don't want to trash it? Any help would be greatly appreciated! Thanks!
 
There is an "Amplifiers - Class D" subforum that may result in more usable responses than "Everything else". You can use the "Report" button to report your own post, and then ask the moderation team to move the whole thread to the "Amplifiers - Class D" subforum.

I haven't a clue what causes your problem, but I do have some questions:
1. Have you tried to clean the connectors of those plug-in modules with isopropyl alcohol or something else?
2. Any solder connections of connectors gone loose?
3. Are there batteries or supercapacitors anywhere?
4. Could you post or link to a schematic of the thing that detects whether there is a signal?
 
@MarcelvdG

Hi there! Thanks for your reply! I have asked for this thread to be placed in the "Amplifiers - Class D" subforum as you said.

To answer your questions, There are no batteries/super caps involved. I really don't believe that any solder joints are loose, and also the connections can't possibly be dirty or corroded as far as I can see. It appears to be something in the circuit that just all of a sudden, it switches between ON and then Standby, then it will play for a minute and cut off to standby even when a signal is going through. It's just odd how it will work fine for a while then all of a sudden it goes into this switching mode. I will see if I can find a schematic online somewhere and perhaps I can provide a link to it.

Here is a link to the only thing I could find giving information on the 1200as2 module. I can not find a schematic for it!
https://doc.soundimports.nl/pdf/brands/ICEpower/1200AS1/ICEpower1200AS1-2-Datasheet_1_6.pdf
 
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There's nothing special about troubleshooting a class-D amp in particular. You will not get far irrelevant of where you ask the question... if you can't find a detailed schematic/circuit diagram.

Have you checked the ICEpower1200AS2 pdf, page 56, Figure 31? That should give you some idea about 2 ways LEDs are being driven... and could be enough if you are ready to trace the LEDs drive signal(s) backwards... just use standard precautions required for SMPS troubleshooting... ground isolation, probe(s) set to 10:1... and maybe even differential probes (ground not really a ground :))

Good luck.
 
@StigErik

Hi there! I have attached some photos of what I built years ago. I had ordered an enclosure from a manufacturer in Italy. I was told that I'd have plenty enough heatsink for cooling the 1200as module as this aluminum enclosure I purchased would do the job well. Just my opinion, but the bottom of the enclosure has never even got over warm! I can tell you that my home electricity varies from 108VAC to 118VAC. So I purchased a variac to try and keep the proper voltage :(
 

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You should have mounted the module on one of the sides instead of the bottom plate. The idle loss is 35 watts, which will require better cooling in my opinion. I have 2000AS2 modules, which have virtually the same idle loss. I found I had to use very large heat sinks on them.

Your problem has appeared over time, right? Could be that the module is faulty….
 
I tried disconnecting the wire that goes to the amber LED and I can still hear that clicking noise. The problem with disconnecting both the speakers and the RCA input connectors is that the amp will not get a signal. This seems to only happen when a signal is being passes through. It appears that this problem occurred after years of use. It started maybe around 6 months ago, and I had unplugged it for some time, then tried it again, and it worked for a couple of weeks and then started doing the same thing! If someone here could tell me what I could check and perhaps something that I could fix myself, I'd keep it. Otherwise I may have to scrap it and build one using the Purifi components or perhaps something better with a good PS. I believe I can keep the enclosure and other components I already have inside the enclosure.
 
@StigErik

Any recommendations that can take me to another level over these ice amps? I'd like to be able to build something that would enable me to upgrade or change parts if they fail. Looks like these Purify modules have good reviews, but what if something on the boards just happen to go haywire? I guess I'm thinking futuristic here..lol
 
Disabled Account
Joined 2008
@StigErik

Any recommendations that can take me to another level over these ice amps? I'd like to be able to build something that would enable me to upgrade or change parts if they fail. Looks like these Purify modules have good reviews, but what if something on the boards just happen to go haywire? I guess I'm thinking futuristic here..lol

Hypex Ncore, NcoreX, Nilai, Purify Eigentakt will all perform better than any ICEpower, at least in theory. Problem is, as you have experienced, is that it's difficult or impossible to repair these modules when (not if...) they break down.