Help, I fryed my Blues Junior ... can I salvage it? (pics)

[indolent_music]

Well, the title says it all. I fryed my Blues Junior a few weeks ago after accidentally switching the pre/power tubes and replacing them in the wrong position. Damn thing caught on fire!

When it receives power it will not turn on and I am assuming I fried an IC chip or interrupted signal flow somehow, thus it does not function at all right now. It's a Blues Junior, so I'm not looking to spend a couple hundred dollars to fix it. Any suggestions?

Thanks,
Andrew

PS - I know, I know, what a dumb***

 

[shark_bite]

Check out S2 amps... for some extra money, you might be able to get a really cool amp out of it, and since they gut the BJ insides and replace them with handwired guts, they probably don't need anything you broke.

 

[wsaraceni]

looks like a hole burnt right through the board. i agree with sharkbite. i think with the money you spend having a tech look over it (i assume you'll need a tech since you didnt just fix it already) it would probably be cheaper to gut and put in a handwired board. if not, you could probably sell it to someone who wants to gut one for themselves although i cant imagine it would be worth a whole lot.

 

[big mike]

That board is toast.

 

[indolent_music]

Any idea what this would go for price wise if I were to just sell it? I haven't a clue ...

 

[PatrickE_FenderADV]

BillM is on TGP and posts often... maybe he can offer some insight since he is a BJr expert. From my perspective, it's toast and I think the s2 option is on you now. BUT... they're pricey. I think it's over $400. Google S2amps.

 

[indolent_music]

BillM is on TGP and posts often... maybe he can offer some insight since he is a BJr expert. From my perspective, it's toast and I think the s2 option is on you now. BUT... they're pricey. I think it's over $400. Google S2amps.

Thanks, I'll look into that. Might just sell locally if I can, or possibly part out. It's basically a nice 1x12 cab now ...

 

[shark_bite]

BillM is on TGP and posts often... maybe he can offer some insight since he is a BJr expert. From my perspective, it's toast and I think the s2 option is on you now. BUT... they're pricey. I think it's over $400. Google S2amps.

True, but think of it this way... if you don't have a BJr, it's more like $800. You buy the amp, then you buy the conversion. That's still a pretty good deal considering what they give you back, at least as long as they give you what they say they're giving you - I've never played one myself so I'm not exactly an authority on the subject. If I had a dead amp and it would only cost me $400 to have it wired to the spec of any amp I want, though? I'd probably jump on it, considering the alternative would be a dead amp I cannot use and not just a "lesser" amp (stock BJr in working order). Let's put it this way -- if it were me, I'd be seeing this unfortunate incident as pushing me to try something I've been curious about but never curious enough about to pull the trigger.

On the other hand, the OP has a possible answer right there... see if anyone else is interested in grabbing this thing for a couple hundred bucks and going the S2 route themselves. It'd be cheaper for them, and you could at least get a little money back out of it.

 

[big mike]

Problem is, I don't even think you can get a couple hun for it now.
It fried the board...did it take the transformers with it? The whole thing is now suspect except for the cab and speaker.

 

[PatrickE_FenderADV]

True, but think of it this way... If I had a dead amp and it would only cost me $400 to have it wired to the spec of any amp I want, though? I'd probably jump on it, considering the alternative would be a dead amp I cannot use and not just a "lesser" amp (stock BJr in working order). Let's put it this way -- if it were me, I'd be seeing this unfortunate incident as pushing me to try something I've been curious about but never curious enough about to pull the trigger.

Very good point... you could pick the 5E3 conversion and turn the BJr into a Deluxe. Get better components and all of sudden you have a killer amp that maximizes your initial investment in the Blues Jr without selling off bits and pieces and losing cash.

 

[jcollins]

So did you put the power tubes in the preamp tube sockets? Visa versa or
both ways?

 

[indolent_music]

Very good point... you could pick the 5E3 conversion and turn the BJr into a Deluxe. Get better components and all of sudden you have a killer amp that maximizes your initial investment in the Blues Jr without selling off bits and pieces and losing cash.

Wow, just looked at the S2amps site ... evidently I can turn my BJr into a 1974x, neat!

 

[indolent_music]

So did you put the power tubes in the preamp tube sockets? Visa versa or
both ways?

Unfortunately, both ways.

 

[jcollins]

There are labels silkscreened onto the board next to the resistors and capacitors. Can you tell which ones are actually burned up or browned?

Did the end of that big capacitor blow out?

Did any of the fuses open up?

Is the circuit board itself burned?

If you can't read the circuit board the layout is here:

http://www.fender.com/support/amp_schematics/pdfs/Blues_Junior_Schematic.pdf

 

[dvnator]

If you are into soldering this could be a fun project...
http://guitaramplifierpcbs.com/liteiib.aspx
as long as the transformers are good.

 

[Billm]

This is a simple repair. I've fixed a bunch of these. The big 2.2K resistor is very likely the only part that needs replacement, despite appearances.

Loosen the board--instructions on my site: http://billmaudio.com/wp/?page_id=17.

Clip the damaged resistor, R47. Unsolder the stubs from the rear.

Use an X-acto knife to scrape away the burnt, charred portion of the board. Clean up the smoke damage with a little Bon Ami on a damp rag. An eraser helps, too. Inspect the cap for damage, chances are it's fine. If you see any tan foamy stuff around the + lead of any of the filter caps, replace all of them. The IC electrolytics suck anyway.

Mix up some 20 minute epoxy and get some rough-woven cloth. Wet the edges of the burn with epoxy. Soak the cloth with epoxy and patch the hole. Add epoxy to fill. You only need a fingernail-sized piece of cloth.

After it cures, put it back together. It should be fine.

You might want to inspect the ribbon cables for burns at either end, but they're probably OK. It seems like any tube short or operator error (being kind here ) just kills R47.

 

[big mike]

Wow. Good info Bill, thanks for sharing.

 

[JDJ]

Time to gut it and put in a tweed Champ or Harvard or Princeton circuit.

 

[evanjackson]

I did the same thing to my Pro Junior...don't feel bad.
But now thanks to Bill M I can fix it maybe...

 

[indolent_music]

This is a simple repair. I've fixed a bunch of these. The big 2.2K resistor is very likely the only part that needs replacement, despite appearances.

Loosen the board--instructions on my site: http://billmaudio.com/wp/?page_id=17.

Clip the damaged resistor, R47. Unsolder the stubs from the rear.

Use an X-acto knife to scrape away the burnt, charred portion of the board. Clean up the smoke damage with a little Bon Ami on a damp rag. An eraser helps, too. Inspect the cap for damage, chances are it's fine. If you see any tan foamy stuff around the + lead of any of the filter caps, replace all of them. The IC electrolytics suck anyway.

Mix up some 20 minute epoxy and get some rough-woven cloth. Wet the edges of the burn with epoxy. Soak the cloth with epoxy and patch the hole. Add epoxy to fill. You only need a fingernail-sized piece of cloth.

After it cures, put it back together. It should be fine.

You might want to inspect the ribbon cables for burns at either end, but they're probably OK. It seems like any tube short or operator error (being kind here ) just kills R47.

Crap. I sold it. Oh well ... I will pass this on to the new owner.