ICE3B0365J Troubleshooting (W200 Sub)

[R_J]

Re: ICE3B0365J Troubleshooting (W200 Sub)

Scratch that, I left it alone for an hour and it suddenly started working again...the behavior of this board has me baffled.
Just left it with the volume up full (low input so as to not annoy the neighbours), after a few minutes it cut out went to flashing and then kicked back in again after a few seconds...going to leave it running and monitor it.

Have you checked the AMP board? I suspect a poor connection on the amp board may be causing it to go into protection.

[CapLeaker]

Re: ICE3B0365J Troubleshooting (W200 Sub)

Post some pictures of the amp board. Maybe there is a cold solder joint somewhere there?

[SFB]

Re: ICE3B0365J Troubleshooting (W200 Sub)

I did have a look at it but didn't see anything obvious - it is all SMD (pictures attached - Ignore the yellow and orange wires as they are just extending the LED cable as it is only just long enough to connect when the case is closed)

Measured voltages on the 102 cap in the bootstrap on the 51ohm - When it works 188V, when it does a false start and stays constant red (he said it has always done this at times and he needed to restart) 162V, and when it is flashing red a pulsing reading from 158-240V. It is working more than not after switching out the R31, R38 and R40 resistors with 1/4W metal ones, and was actually a challenge to get it to flash - leave it on a while then a fair bit of on/off.

It seems I'm creeping closer to a resolution...

[CapLeaker]

Re: ICE3B0365J Troubleshooting (W200 Sub)

Ok… I wanna know which board is causing this. If you look at your first post, the second picture. Look at the secondary side of the optocoupler. One leg traces back to a pin on the amp board. Check it out. Somewhere it looks like there is a half broken trace. Maybe worth resolderig the whole line up.

[SFB]

Re: ICE3B0365J Troubleshooting (W200 Sub)

I had actually resoldered from that point up to the pin when I did the rest recently as I had noticed the broken bit, but with you mentioning it I decided to run wire down and it seems to have done it. Been on over an hour and cannot get it to turn red or flash. Not counting my chickens yet and going to mess with it more, but tentatively hopeful...

[SFB]

Re: ICE3B0365J Troubleshooting (W200 Sub)

It's gone again, but only once I had put it back inside for half an hour...it has got to be a heat issue....going to heat and freeze stuff tomorrow.

[CapLeaker]

Re: ICE3B0365J Troubleshooting (W200 Sub)

Dang. Would have been too good to be true. Lol

[SFB]

Re: ICE3B0365J Troubleshooting (W200 Sub)

Yeah, starting to get on my nerves a bit now haha

Dang. Would have been too good to be true. Lol

[CapLeaker]

Re: ICE3B0365J Troubleshooting (W200 Sub)

Obviously something is turning the PSU off? Maybe force it to stay on?

[SFB]

Re: ICE3B0365J Troubleshooting (W200 Sub)

That would blow something though wouldn't it? It is obviously tripping because it is detecting an issue.

I can't even get it to come on again now...I don't understand how laying a bit of wire to re-enforce a tracer, desoldering-checking-resoldering, reflowing connections, just taking measurements or even having the board outside/inside can completely change it's behaviour. So far I have had it working, static red light, slow flashing red light, fast flashing red light or nothing at all, and completely random combinations of all or some of them.
I imagine if it was the other board you wouldn't see this happening as there are no changes happening there?

[CapLeaker]

Re: ICE3B0365J Troubleshooting (W200 Sub)

Right now I wouldn’t care much if something blows up and we don’t even know why it shuts down.

[SFB]

Re: ICE3B0365J Troubleshooting (W200 Sub)

Fair point. I'm assuming to force it to stay on I'd need to inject the 15V on the VCC connection, or the expected voltages on the pins for the amp board. Would mean I need to get myself a desktop PSU...a thermal camera would be helpful too, but no way I can afford one of those at present haha

[CapLeaker]

Re: ICE3B0365J Troubleshooting (W200 Sub)

There are cheap CV and CC bench PSU’s available. This way you could adjust the current too.

[SFB]

Re: ICE3B0365J Troubleshooting (W200 Sub)

I think I've got it. Before getting a bench PSU and forcing it I decided to take the last bridge off as it was working better prior to no avail, then went round and reflowed every single connection (some bubbled) before doing a meticulous clean with alcohol and qtips. Worked straight away but after an hour it stuttered and noticed some molten flux had seeped out of somewhere, so cleaned that and now it has been solid for 19 hours inside the unit. Just cleaned up a few more bits of liquid flux and still solid. Would have liked to say it was a join, but it looks like flux somewhere has been melting when it gets hot and tripping it. I have been cleaning the board every time but can only assume with the board damage it had gotten somewhere I was missing while cleaning. Is that likely?

[CapLeaker]

Re: ICE3B0365J Troubleshooting (W200 Sub)

I ran into this exact same issue on an old nortel telephone system. The fix was to take the component out, clean the hole and resolder it. Funny thing is this system worked for like 15 years no problem before this issue rose up.
Just resoldering that component didn’t help and leaked old flux like crazy.

[SFB]

Re: ICE3B0365J Troubleshooting (W200 Sub)

Jeez...no wonder it was being intermittent and everything else checked fine then. Definitely something I'm going to keep in mind for future though if the issue is being elusive. He has taken it now and it hadn't faltered in over 24 hours. I did notice residue on the back plate during that last clean so hoping whatever it was I either got or just burned off with the heat. I have learned a lot though, and thanks again for your help and advice with this, it is very much appreciated. Suppose it is back to my sub now then and try and figure that out now haha

[CapLeaker]

Re: ICE3B0365J Troubleshooting (W200 Sub)

I found the problem using my oscilloscope and my hot air station. Hopefully that fixes it now for good.

[SFB]

Re: ICE3B0365J Troubleshooting (W200 Sub)

An oscilloscope and a bench PSU are the 2 things I don't have, though the latter is planned as soon as I have some spare cash. I have seen some reasonably priced secondhand scopes but right now I wouldn't know how to use one anyway lol