Anyone know anything about SSL EVO5000.1?

[jacampb2]

I bought a pair of bad class D amps on a whim and I am having some issues with this one. I initially tried to power it through a 1 ohm limiter, it tries to draw about 9 amps. I pulled all the PS fets and tried again, still drawing about 9 amps. I then pulled all the rectifiers, still pulling 9 amps. I checked the RP protection diodes, they are fine. I found the filter caps on the output filter were bulged, so I pulled them, still pulls 9 amps. I then pulled the PS caps thinking maybe one was shorted, and it's still the same.

I think I have pulled about everything that could possible be a direct short across power and ground. I tried pulling and twisting the transformers, and could get the current draw to change. The transformers are really mounted down well. There is not a lot of movement.

So, are there any common problem areas I might be overlooking? In the pic below you can see what looks like some haze on one side of the board, maybe water damage? Any other ideas?

Here are the pics:

Full Size:Clicky

Full Size:Clicky

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Full Size:Clicky

Thanks,
Jason

 

[Perry Babin]

Do you read 0 ohms across the B+ and ground terminals?

 

[jacampb2]

Yes, or very close to it. I think .11 ohms actually.

 

[Perry Babin]

I would go back and doublecheck for solder bridges at each PS FET location.

It's possible that you had one problem and a solder bridge is a second problem.

It's possible that the transformer winding is shorted to the board.

Before you started removing parts, did you read the same resistance across the terminals?

Was the current draw there without remote?

 

[jacampb2]

Draw is there without the remote. I did go through all the power supply fet locations after pulling them and sucked off most of the solder. I didn't go over them with braid yet, but I will give it a shot tomorrow.

I did not think to measure resistance across the battery terminals until it was late in the game. I did have my meter in series measuring current every time though, it was always between 9.36 and 9.57 amps, so that would lead me to believe there was not much change in the resistance across the terminals.

I really should not have started pulling parts willy nilly, but one of the PS fet solder joints looked kind of charred and corroded, so I pulled it first to measure it, and when it tested good I just popped out the rest of the FETs, then I just got carried away...

Thanks,
Jason

 

[jacampb2]

It actually looks like those two caps to the left of each transformer are also across the battery supply. When I didn't find any of the other six bad though, and they are showing no signs of bulging or leaking, I decided not to keep pulling them. If I don't find any solder bridges tomorrow, I may go ahead and pop them off too. It doesn't take that long, but I actually put the brakes on on this one because I could feel myself getting carried away and I needed to step back and think about it some more.

Thanks,
Jason

 

[jacampb2]

I'm going to go ahead and admit that I am an idiot! I found the short, it was indeed a solder bridge. The stupid thing is that I had vacuumed the solder off most of the pads on the top of the board, but apparently I forgot to hit the bottom side. I should have seen it in my own pictures. I guess I was in to much of a rush. I'm off to see if I can find the component that had caused the initial problem. Will report back soon.

Thanks Perry for reminding me to check the completely obvious!

Thanks,
Jason

 

[jacampb2]

Quick question, how critical are the output filter caps? These were 220uF 100Vdc, I might be able to come close, but I doubt I hav the same. I'm thinking just for testing purposes.

Thanks,
Jason

 

[Perry Babin]

I'd use the original value. Those are the 4 for the output filter at the speaker terminals, I'm assuming. The rest for the primary side filters will be rated for much less voltage.