Fender Blues Junior Power Problem Help

[tubes09]

Briefly; Turned on the power switch on my Blues Jr and the on power light indicator doesn't turn on and the tubes don't light up. All fuses appear good. Anybody have any ideas of what I should be looking at to repair this amp?
Thank you in advance. Jack

[stokes]

You say "all fuses appear good".Did you check them with a meter? Looks can be deceiving.

[tubes09]

I'll replace the two fuses just to make sure. I want to add that although the light indicator doesn't turn on and the tubes don't light up, I can hear a low volume hum like sound,very low, indicating that some power is getting through. But the amp won't power up. Also, I was running a Fulltone OCD pedal with the amp at low volume. Could that (OCD) over loaded something and caused a short? Thank you again. Jack

[CharlieP]

Originally Posted by tubes09

I'll replace the two fuses just to make sure. I want to add that although the light indicator doesn't turn on and the tubes don't light up, I can hear a low volume hum like sound,very low, indicating that some power is getting through. But the amp won't power up. Also, I was running a Fulltone OCD pedal with the amp at low volume. Could that (OCD) over loaded something and caused a short? Thank you again. Jack

You may find other ceramic fuses inside the chassis Too. When was the last time you changed the power tubes? Just a thought.

[Enzo]

Always pull fuses and test them with a meter.

If fuses are OK, then we start looking for a bad side on the power switch, wires of the mains wiring, bad power cord, etc etc.

[Robert M. Martinelli]

Originally Posted by tubes09

I'll replace the two fuses just to make sure. I want to add that although the light indicator doesn't turn on and the tubes don't light up, I can hear a low volume hum like sound,very low, indicating that some power is getting through. But the amp won't power up. Also, I was running a Fulltone OCD pedal with the amp at low volume. Could that (OCD) over loaded something and caused a short? Thank you again. Jack

Hi,
according to the symptoms you describe your amp is missing the 6,3VAC for the heaters' supply. The "power on" light ( or LED ) gets its supply from this line ( via a dropper resistor ), and this could be the reason why the light/LED stays off ( unless, of course, it is blown ) together with the tubes. The faint hum you're hearing could be hum from the +B line making it to the speaker through the OT, this indicates that the rest of the amp is getting power, so I'd say the power switch is ( probably ) OK and take a close look at the heaters' power supply area.

Hope this helps

Best regards

Bob

[tubes09]

Problem solved, tested the fuses and the 5amp fuse(small one) was blown.
Interesting, looking at the fuse it appeared intact. Must have fried
at the bottom undetected. The amp is up and running again. Thanks everyone for your help Jack

[CharlieP]

Enzo was right again as usual! It's great to have him around.

[Robert M. Martinelli]

Originally Posted by CharlieP

Enzo was right again as usual! It's great to have him around.

Hi Charlie,
While I completely agree about Enzo, as I'm very grateful to him too, I'd like to point out that I don't feel like my diagnosis was wrong - If you look at my last post, I stated : "according to the symptoms you describe your amp is missing the 6,3VAC for the heaters' supply" - and the 5 Amp fuse actually IS the Heaters Supply fuse.

Well...I guess the most important thing is that Jack managed to fix the amp...

This forum's one of the last good "places" left on Earth IMHO.

Best regards

Bob

[txstrat]

Originally Posted by voxrules!

This forum's one of the last good "places" left on Earth IMHO.

Bob, I agree

cheers

Matt

[CharlieP]

No dis-regard is intended for anyone's input here. I was directing my reply to importance of actually checking fuses by Enzo's experience and yes your reply was on the mark too. I am a newbie at tube amps and have been following several forums which have helped me very much. Fortunately Enzo follows them too, here and in the Peavey forums. Also I know that other forum members have a lot more experience than I have.

[tubes09]

Just want to say again that I got lucky on this one with a blown fuse,
otherwise it may $$$$. Thanks again for all the pro input.

[Robert M. Martinelli]

Originally Posted by CharlieP

No dis-regard is intended for anyone's input here. I was directing my reply to importance of actually checking fuses by Enzo's experience and yes your reply was on the mark too. I am a newbie at tube amps and have been following several forums which have helped me very much. Fortunately Enzo follows them too, here and in the Peavey forums. Also I know that other forum members have a lot more experience than I have.

Hi Again Charlie,
Maybe I owe you an apology, re-reading my post I think I over-reacted.....
when I posted that I had just been robbed the "fruits" of a big project of mine at work ( I guess I'm born in the wrong place for meritocracy to be found ) so I was kinda touchy at that time.
Peace
Bob

[Enzo]

Hey Bob, we're all glad you are here. Sometimes I want to emphasize some particular point, so sorry if it seems directed at you, it wasn;t.

[Robert M. Martinelli]

Enzo,
I felt the need to apologize because, telling the truth, re-reading that post I felt I kinda over-reacted, and I felt bad about it.....
Thanks for your kindness and concern.
Bob

[CharlieP]

Originally Posted by voxrules!

Hi Again Charlie,
Maybe I owe you an apology, re-reading my post I think I over-reacted.....
when I posted that I had just been robbed the "fruits" of a big project of mine at work ( I guess I'm born in the wrong place for meritocracy to be found ) so I was kinda touchy at that time.
Peace
Bob

Bob:
We are all going thru some touchy times with the economic situation. I am only getting 2 days a week. Good thing I am drawing a pension too! Your apology is gratefully accepted. I am glad you are here adding to all the knowledge that is in this forum. A thank you for all who are doing so too!