Up In Smoke!

[roughcut studios]

A friend brought his mixer to me for repair. He figured that since I build tube amps, that I should be able to fix his solid state mixer. I am not so familiar with solid state power supplies, and am lacking any documentation for this unit. I was hoping for some help identifying a vaporized component on an Alesis Studio32 mixer power supply board. I tried to get info from Alesis, but they have new owners since this unit was built, and so they no longer offer any support for this model. No help at all. Has anyone got a schematic for the power supply, or is anyone willing to ID the missing part? All that's left is the stubs of two leads, and a small crater that took out any labeling that may have been close.
Check out the photo,...what was it?

Thanks,...Jon

[CraigW]

What is the letter designation for the damaged part ? Can't tell in the pix.

[Rich Bass]

Maybe

I'm gonna take a guess. Could it be a P.L. LED?

[km6xz]

I have the print back in storage, little good that is 5,000 miles away. Can you use a Q-Tip with alcohol to clean away some of the burn marks. They had a habit o blowing up bypass caps but it has been a number of years since I have seen one. If the mark is a bypass the overall mixer should work ok still. What are the symptoms?

[roughcut studios]

I cleaned up the burn marks as best I could.
There are no marks or component ID's left on the board.
The symptoms are, " It just went dead".
I believe if I could get this power supply back up, the mixer will be fine.
This mixer was used a lot, then stored for a couple of years, then returned to service.
It lasted about two months, then POOooff, it let out that dreaded little puff of smoke.
there was nothing left of the part to autopsy, just a crater in the board, so it went up pretty good!
There are the remains of two leads at the bottom of the crater. Could be a cap, but what value?
Anyone?

[km6xz]

If it is a cap, it will run without it. The size of it suggests that it is not a filter cap. Where does the supply stop supplying..? The connectors on the left go to the power transformer, do you get appropriate AC between those pins with the transformer connected? Do the rectifiers have appropriate DC on their positive and negative terminals? Do any of the Voltage regulators work? Fuses ok?