So I'm playing away at a gig last night and my amp completely cuts out for about 10 seconds, them comes roaring back on. Never lost power and the power light was one, just went silent and came back. Played one more song and right near the end, the amp goes out again.
I call a short break and run out to the truck to grab my spare PJ. That's the best thing about these little guys. I paid $200 for each of them and they fit on the floor in the back seat until needed. Nice. Second amp performs flawlessly all night.
I opened up the silent PJ today and spy around in there and spot my problem, R32 (power resistor) is fried. Not blown up, but instead of measuring 2.7k it's something like 2M. It was a little spattery-looking with most of the pain scorched off so it had to go. Luckily, the PCB underneath is not damaged in any way that matters. A tiny little brown spot, but there's no trace on the other side so I'm not sweating it.
Upon looking over the PCB I notice that the screened graphic for that resistor is a lot bigger than the actual component soldered in there. Since I need to refer to the schematic anyway I look at the power rating in addition to the R value. Sure enough - it calls for a 2W and it came from the factory with a 1W soldered in there. I dig through my stash and find a nice big honking 3W Allen Bradley CC from my stash of salvaged parts, test it to verify the color code (it tests at 2.75k) and pop it in there. I also mount it nice & high up off the PCB with about 1/4" of space under it - unlike the original which was soldered tight down on the board. Amp fires right up and sounds awesome as usual.
So now my list of Fender goofs on this amp includes not only the bundling of AC/signal/output wires together and not twisting the heaters, but a power resistor half as stout as it should be. This may be a one-off mistake, but if you have one of these, take a look at R32 and make sure it's a nice big fat 2W or better resistor, not a skinny little thing like the 1W original that popped in mine.
I still love these amps, don't get me wrong. I just can't believe a company like Fender would manufacture something with so many little easy to fix design goofs in it. Of course it was built to a price point, but come on. A total of about $1 fix the issues to double reliability? And not do them at the factory?
Just another excuse to build an 18W or something in one of these I guess. Not like that's a bad thing.
Cheers,
- JJ