Phoenix Gold Phorum

I have an Eclipse 3640 4 channel amp that I sold on ebay. Buyer sent it back to me, said it bad. I installed it back into my car and it works fine. So out of curiosity I decided to open it up and see if there was any problems internally.

You will see in the picture below that a power transistor is obviously damaged. What I don't understand is why it's still working???



I disassembled the amp further and found solder traces on the other side of the amp may have been fused together with solder from excessive heat.




I am going to replace all of the transistors.
But what about all the solder on the traces? In my opinion it does not look factory, I think it actually got hot enough to melt solder. Should I clean all the solder traces up after replacing the transistors?

What are your opinions?

I see alot of silver solder on there

Everywhere the solder is SHINY....was fixed or worked on by someone other than the factory.

Yes, I would remove the solder so the traces are independent from each other again. I have seen solder balls in head units that have come free and shorted units before. Could have been poor soldering there too. Good Luck.

The solder on the back is normal. That stuck when the board was wave soldered. Machines or humans put all the parts in the board and then it goes to a wave solder machine where it actually skims across the surface of molten solder in a big tank. This quickly (and usually cleanly) solders all the connections. A board like that one is actually designed for solder to stick to it, which then makes the traces thicker (copper plus the extra thickness of solder). This allows the traces to conduct more current.

That amp looks to have four power supply transistors. Two are on each leg of the transformer. It is still working because the failed one is burned open. One is handling a leg on the transformer and the other two are handling the remaining leg. Do not run it hard like this, as it is unbalanced which will cause additional problems. If the failed transistor were burned closed, it would drain max current, and either blow a fuse or your power source.

I suggest you replace those four transistors, and the four resistors which drive the transistors. When things get out of control with the power supply, the resistors are likely damaged as well as the transistors.