It is currently Mon Mar 16, 2020 7:06 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 6 posts ] 
Author Message
Post subject: Amp gurus: I could use a little help
Posted: Sat Jun 18, 2016 3:20 am
Offline
Amateur
Amateur
User avatar

Joined: Wed Aug 27, 2014 9:25 pm
Posts: 176
I did a simple speaker swap today, and when I turned the amp on, no sound.

I hooked it up fine, but when I looked at the back of the amp to check the speaker connection, I noticed one tube wasn't glowing (the one nearest the PI.

I looked inside the amp at the socket connections, everything looked ok, wiggled some stuff around to see pin solder joints. Then I tested it again, all 4 power tubes glowing, no sound.

I took the shields off of the preamp tubes, none of them are glowing.

I looked for an internal fuse, don't see one, but the main seems ok.

I put in all new tubes (pre and power), still the same result.

Any ideas what might have caused all of this? I played the amp an hour before the speaker swap, everything was fine. I played both speakers earlier, both worked fine. But I did the swap, and the amp just makes no sound now.
Here's a look at the inside of the amp if it helps. It's a custom build, so I have no schematics.
Image

Image

_________________
YMMV


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Amp gurus: I could use a little help
Posted: Sat Jun 18, 2016 3:50 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
Post on the amp section, more answer there.

1- Pilot lamp glow or not ?
2- Fuse look good ; with your eyes you can't tell, use meter.

3- Did you plug speaker at the right jack ? Good solder ?
I see 2 jacks, one on each wire !! What is that ??
There might be something wrong there
4- Did amp was working fine just before you swamp the speaker ?

Please answer


Top
Profile
Post subject: Re: Amp gurus: I could use a little help
Posted: Sat Jun 18, 2016 8:01 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Mon Jul 16, 2007 6:51 pm
Posts: 25353
Location: Witness Protection Program
I'm guessing a circuit mounted fuse blown. The chip type.

What model/make of amp? Get a schematic or trace from OT and test.

_________________
Being able to play and enjoy music is a gift that's often taken for granted.

Don't leave home without it!


Top
Profile
Post subject: Re: Amp gurus: I could use a little help
Posted: Sat Jun 18, 2016 9:15 am
Offline
Amateur
Amateur
User avatar

Joined: Wed Aug 27, 2014 9:25 pm
Posts: 176
stratele52 wrote:
Post on the amp section, more answer there.

1- Pilot lamp glow or not ?
2- Fuse look good ; with your eyes you can't tell, use meter.

3- Did you plug speaker at the right jack ? Good solder ?
I see 2 jacks, one on each wire !! What is that ??
There might be something wrong there
4- Did amp was working fine just before you swamp the speaker ?

Please answer

Power tubes glow, preamp tubes don't.

The two jacks are the speaker outs.
Image

Image

The amp worked before the swap, then no sound after. And the preamp section is dead, but not power section. It's the 3rd speaker swap I've done since I've had this amp. 1st time this has ever happened.

_________________
YMMV


Top
Profile
Post subject: Re: Amp gurus: I could use a little help
Posted: Sat Jun 18, 2016 9:28 am
Offline
Amateur
Amateur
User avatar

Joined: Wed Aug 27, 2014 9:25 pm
Posts: 176
Miami Mike wrote:
I'm guessing a circuit mounted fuse blown. The chip type.

What model/make of amp? Get a schematic or trace from OT and test.


Mike, this is a custom build I bought a while back at a pawn shop. To my knowledge, there is no schematic available. The word I got was that the builder passed away.

Image

If it's a chip fuse, I'm probably going to need to take it to a tech. I'm not sure I'd be able to identify it. I'll look again though. The picture in the OP is the actual inside of this amp.

_________________
YMMV


Top
Profile
Post subject: Re: Amp gurus: I could use a little help
Posted: Sun Jun 19, 2016 8:19 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Mon Jul 16, 2007 6:51 pm
Posts: 25353
Location: Witness Protection Program
Yea, those buggers are hard to locate & replace....Vishay and Littlefuse have many replacements.

http://www.littelfuse.com/products/fuse ... fuses.aspx

_________________
Being able to play and enjoy music is a gift that's often taken for granted.

Don't leave home without it!


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: Mr. Nylon and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: