Problem BF Pro Reverb

[ricach]

I have a friend who has recently powered up an old BF Pro Reverb that he hasn't used in years (worked back then). He told me the tubes were glowing, but no sound. I'm guessing caps are the problem, but he does not know of any tube technicians in the city he lives in (Peoria, IL). He's somewhat capable with an iron, but very intimidated by the rat's nest he see's inside.

Any easy troubleshooting suggestions for him? I recommended he just replace the board - caps and all - with a populated replacement, however I can't find anyone who sells the AA165. Will something else work instead?

Thanks in advance for any and all help.

[52 Bill]

Any amp that has not been used in a number of years is likely to have developed a number of problems, but depending on how it was stored, I doubt that it would require the replacement of the board. Has he checked the tubes?

If the amp is dead silent, check the speaker, the wiring and the plug/jack for corrosion etc. Oxidized connections at all of the jacks would be the first thing I'd look at. Then check the tube socket connections.

Hope this helps.

[myfoot]

There's a music store called FLores Music in Peoria that does repairs.I don't know anyone who's used them so can't vouch for quality of work. Talked to the owner once when we stopped to look around. seemed like a nice guy
http://www.myspace.com/floresmusicstore

[Alex R]

Yes, the new board idea is overkill really. If he has the skills to fit a new board then it might be worth his while joining this forum, where he'll get plenty of support in sorting it out, and only the one initial lecture about lethal voltages lurking in caps... whoops, there it went.

And if he's not that confident then a good tech will be able to sort it out. These amps are not hard to work on so I'd advise he distrusts anyone who says they are.

[Enzo]

I can't imagine throwing away the board and looking for a new one. That is like throwing away the car engine for having a bad sparkplug.

These Fender amps are about as basic as amps get. If your guy thinks this is a rats nest, don't let him look inside a MArshall of recent vintage. This is an easy problem, no sound, and any amp tech could sort it out pretty quick.

And I seriously doubt your caps are involved. Bad filter caps either blow fuses or leave the amp with a hum. They don't usually kill the sound. And the little coupling caps throughout the circuit can interrupt the signal path, but the amp will still make some sort of sound.

Check the speaker, try tube subs, check for missing high voltage at the tubes.

[ricach]

The idea of replacing the board is one of economics. Since he really doesn't feel he has the skills, and since he does not have the test equipment to troubleshoot it himself, he is destined to pay a tech (he does not know or know of having a good reputation) to troubleshoot and repair. And since I always read about the need to (eventually) re-cap old amps anyway, I feel in the long run it would be his cheapest, and best, longterm solution.

[Alex R]

The filter caps aren't on the board, for one thing. Most everything on the board will be good, for another. The board has many confusing connections to pots and valve bases; replacing it is a really big job; fixing the amp is a small job in all likelihood. Replacing the board would take more skill than fixing the amp I'd say. Boards are not easy to get - kit versions are sold but they are unlikely to be a screw-in replacement. Nobody I know of sells replacement boards as repair items.

There is probably not too much wrong with this amp. Best bet is a power valve shorted and blew the HT fuse. Maybe one or two other components. Try swapping in a new power valve or two; buy a few fuses.

[Bruce / Mission Amps]

The idea of replacing the board is one of economics. Since he really doesn't feel he has the skills, and since he does not have the test equipment to troubleshoot it himself, he is destined to pay a tech (he does not know or know of having a good reputation) to troubleshoot and repair. And since I always read about the need to (eventually) re-cap old amps anyway, I feel in the long run it would be his cheapest, and best, longterm solution.

Good Grief...it will be way too expensive to do that.
The cheapest thing for him to do is pull the chassis from the cabinet, (again 'cause it sounds like he knows what it looks like inside)...pack it up and send out to someone here on this forum who could probably get it running well for $60-$100 and that might even include all the caps that are really bad.
Geeze.. I or others here would probably look at it for free and tell him what is wrong with it.

[Alex R]

Steady on ol' chap. Such a thing as a bench fee... but yeah, a tube and a half hour's work is all it probably is. Take it straight to a tech, not a big chain music shop unless the tech is there before your eyes behind his grubby bench, or at any rate accessible for a chat.

A little off-topic but apropos of chain music shop repairs... Couple of months ago a bloke brought a recent manufacture 100W SS combo to me. It had gone quiet except for some background noise; some LEDs were lit, fuse ok. He'd taken it to a big chain shop in a city nearby who had shipped it to their tech. He had quoted close on $500 (in your money) for a repair, giving no details of the work or the cure. Just the word 'repair', a colon, and that amazing price. I guess he includes their markup in his quote, but even so... Well the bloke paid the bench fee (£35 / $70!) and took the amp back, pretty p'd off because he runs a rehearsal studio and had bought a slew of these amps from the same place just over a warranty period before. It took me a little while to work out what was wrong as schematics weren't available but even ol' hawkeye noticed after an hour or so of headscratching and gurning that a 7818 vreg had been neatly removed from the power supply to the opamps. Fitted a new one - back it all came. Cost: the bench fee, parts inclusive. I'd have assumed that the crazy quotation was due to incompetence and fear of the job if it wasn't for that neatly removed 7818.

Customer service doesn't count for much when you're selling guitars and amps by the cartload to kids through a city shopfront. I guess this is where the UK land value bubble has got us; everyone ripping everyone else off to pay their rent. On the other hand maybe that tech is a sneaky cheating bastard, that could explain it too.

[Enzo]

Some techs are what I call "symptom response" repairmen. They know that when X happens, most of the time replacing Y fixes it. But they don't know why. They know all about the dropping resistors on a Fender Hot Rod Deville, the effects loop jacks everywhere, that little cap on the Marshalls, the stuff in Gerald Webbers books. But they don't know how to troubleshoot. They don't recognize that all amps are pretty much the same, details aside. These are the kind of guy a chain store can find easily, and since as we all know, 80% or more of repairs are simple, he fixes most of what comes in. And the store really is not too concerned when the repair guy recommends a new amp to more customers than he should.