Fender Stage 100 DSP

[nwguy]

Just picked up this amp from a friend. Turned it on and got a very loud hum. Hum is still there with all controls off. Putting a signal source into the input and I get a tone through the amp along with the loud hum. I have no schematic so I am guessing at this point....... A bad filter cap/connection in the section that feeds the power amp.

Any thoughts

Anyone have the schematic

Thanks

[Enzo]

Open teh amp, the two main filter caps should be obvious to spot. Wiggle them, either one loose? resolder them anyway. Now reassemble the amp and power up, is there DC voltage on the speaker output? No? Is the amp quiet now?

[Phostenix]

And if you need the schematic, email consumerrelations@fender.com - they will email it to you.

[nwguy]

Fixed it

Enzo, you were correct. One of the worst cold solder joints that I have ever seen. Re-did it and the amp works perfect. I have heard that Fender amps built on circuit boards are notorious for cold and broken solder joints

[Enzo]

It is broken. The caps stick up and shake, levering themselves out of the solder joint. the joint can arc and erode itself while failing.

very common repair on Fender SS amps of the era.