Did my 5150 just die?

I didn't read into this thread all that much but if nothing else bring it back to Rob. It's a super cool guy and really knows his gear/electronics. Me and him have talked a few times and I even made his website at one point. :D
 
When the amps off take the valves out and have a really good look. You should be able to see if one of the filaments is burnt out or has a gap in it ( exactly like a light bulb)If so that valve is your culprit.
 
I had pretty much the same breakdown on a Bugera I had about a year ago, it turned out to be the transformer, but I returned the thing anyways. Doesn't mean this is your problem too, though.
 
Turns out that the bottom fuse was dead! I just bought some contact cleaner for the power tubes so I'll update everyone in an hour or two. Cheers!
 
colonel kurtz said:
that 3rd fuse may not necessarily be faulty...sometimes they're just made with the window being covered on the inside like that, but that's something that's more common in a slow-blow fuse, which is definitely not what you want in any kind of electronics.

really the best thing you can get for checking fuses is a simple continuity tester...get one at whatever hardware/home improvement place is most convenient. they're only like 5 bucks, and you just touch each lead to one end of the fuse, and if it lights up the fuse is good...no light and it's done for.
Click to expand...

+1

I opened my 5150 head up years back when it didnt work and the internal fuses looked exactly like that with one being solid white.

I replaced the external fuse and the (broken) power tubes and the thing works like a charm.
 
Well I just gave it a shot and changed the fuse and also put some contact cleaner on the power tube pins, no luck. The standby switch still won't light up when I take it off standby and there is no sound from the amp at all. The power tubes glow fine without any foul play so what's my next bet? I can change the other fuses for shits and giggles, but they are work according to my tester
 
Are you getting output through the effects loop? Either on the send or recieve? If not, it may be the PI (phase-inverter). Further up the preamp chain it gets hairier to diagnose. Make sure all your preamp tubes are lit.
 
Ready for the facepalm of the year?

SO when I took out the fuse originally, I had to unplug the cable next to it to get proper leverage to get the fuse out. Guess who forgot to plug it back in after I changed the fuse? ;)

Now it sounds brand new! I only let it warm up for a minute and it's roaring! Thanks again guys, you are all completely lifesavers.

With that being said, anyone need any reamps? :D

Cheers!
 
roflsaurusrex said:
Ready for the facepalm of the year?

SO when I took out the fuse originally, I had to unplug the cable next to it to get proper leverage to get the fuse out. Guess who forgot to plug it back in after I changed the fuse? ;)

Now it sounds brand new! I only let it warm up for a minute and it's roaring! Thanks again guys, you are all completely lifesavers.

With that being said, anyone need any reamps? :D

Cheers!
Click to expand...

Awesome man! Glad to be of service. Might need some reamps soon.. ;)
 
glad you got it sorted out...it's amazing how often seemingly catastrophic gear failures come down to components that cost less than a dollar

but then...you have those cases where transformers and the like go out, and then you're just screwed!
 
I know this is already resolved, but I would like to chime in for anyone for future reference. If the amp makes no sound and the standby light doesn't turn on, it means that there is no HT+ or high voltage supply to the tubes from leaking caps which will subsequently blow the HT fuse or one of the two fuses (if not both) that are responsible for the +/-24v and -50v bias tap have blown, usually from bad tubes. The only other possibility is that the standby switch is broken. If you get no sound from the FX loop send, it means that the HT fuse blew and if you do get sound, the fuse from the +/-25v rail blew.

In the case of the OP it was the low voltage rail's fuse which is responsible for signal clamping in the preamp, and the biasing of the powertubes, which will cause the amp to be rendered useless.

As a rule of thumb, if the standby light doesn't turn on, it isn't just faulty tubes, something else in the amp, usually the fuses went out.
 
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