Fender Yale Reverb silent ..

[dax44]

Hi all - not sure if this would be better directed at a music electronics forum - but I'll give it a go here.

tldr; power section working but no sound out of the pre-amp

So Fender Yale Reverb - just stopped working - don't use it a lot just a spare amp for jams and stuff. Nicely made btw. I have the schematic - the amp is alive from the power stage onwards - the power-amp in jack works. The pre-amp out gives nothing - there is faint healthy sounding hiss and all 3 volume pots seem to work - volume, gain , master all seem to defeat the faint background hiss. So basically there is no pre-amp signal it seems. Checked/cleaned input jack. Touching the pins of the first opamps with a DMM does not give a thing - no pops finding their way through to the power section. All the power rails check out - 15 / 24 / 37V. There seems to be power everywhere just no life. So , my competence level is I can solder and not electrocute myself and use a DMM , I am thinking someone overloaded and blew the first opamp? One - thing - the tone pots were giving strange resistance readings when I took out the board - like 0 - 18k then down to 12k for a 50k pot as I turned - I suspect dirty pots but could they interfere with the signal path?

Sorry for the long read I've added a tldr !

Paul

 

[glenlivet]

I have your amps little brother, the Harvard Reverb II.
Pull the main board.
Flip the board over and just run down and touch up all the POT solder joints.
Then give all the POTs a good cleaning.
(if you already have the board pulled....it's easy)
Made a world of difference for mine.

Fender Harvard Reverb II

Got this in the mail a few weeks ago.....price was right (OK...maybe a little high...) but, I couldn't turn it down......Sweet little 20 Watt solid state amp. I'm guessing maybe early - mid...

geekorama.weebly.com

 

[dax44]

I have your amps little brother, the Harvard Reverb II.
Pull the main board.
Flip the board over and just run down and touch up all the POT solder joints.
Then give all the POTs a good cleaning.
(if you already have the board pulled....it's easy)
Made a world of difference for mine.

Fender Harvard Reverb II

Got this in the mail a few weeks ago.....price was right (OK...maybe a little high...) but, I couldn't turn it down......Sweet little 20 Watt solid state amp. I'm guessing maybe early - mid...

geekorama.weebly.com

Yep crossed my mind , but the joints looked clean ( had the board out already ) - then I now read your post! Ok I’ll be giving that a shot. I’ll report back. And I was out of contact cleaner so that too.

 

[glenlivet]

Yep crossed my mind , but the joints looked clean ( had the board out already ) - then I now read your post! Ok I’ll be giving that a shot. I’ll report back. And I was out of contact cleaner so that too.

If you really want to do it correctly, (unlike me...) you should probably wick the old solder off and use new. If you have a solder sucker it's a quick job. Only takes a few more seconds per pad.
Good luck.
If you pick it up slightly and drop it, do you get any noise from the reverb tank? (a crash from the reverb springs?) It looks like the reverb wet signal feeds almost directly into the power amp section.

edit: turn the reverb way up, to 8 or 9 and do the drop test.

edit 2: pay special attention to the Master Volume POT.

 

[dax44]

yes the reverb channel makes noises - it comes back in after the master volume so signal not getting through volume, gain or master - or the tone control circuit but I think that is paralleled - I think I will resolder all the pots step one , yes I have a solder sucker. cheers.

 

[glenlivet]

Awesome, sounds like you have things well in hand.

 

[dax44]

Still working on it. Ended up making a signal probe. Looking like the 4007 "tube" chip is blown. Got some on order. Came across a number of reviews of this amp while sniffing around - going to have to give another serious listen once repaired, will add a speaker out jack too.

 

[glenlivet]

Still working on it. Ended up making a signal probe. Looking like the 4007 "tube" chip is blown. Got some on order. Came across a number of reviews of this amp while sniffing around - going to have to give another serious listen once repaired, will add a speaker out jack too.

I like my little Harvard. It's not a bad little amp. The Harvards/Yales etc....are a little underestimated in my opinion. They are "just a solid state" amp and often overlooked by many people. I think my Harvard would probably sound a little better with a speaker change, but I'm not sure exactly what to drop in it.
I like that it has great reverb, (at least the Harvard does), FX out / FX in, built in overdrive, and headphone jack.
Pretty good bang for buck in my opinion.
They definitely have that classic "Fender Sound".
I thought about trying to find a Yale just for the extra power, but at this point, I probably won't ever need a larger amp.
Sorry that touching up the solder joints didn't fix your issue. Sure worked wonders on mine.
Glad you found the problem, good luck.

 

[dax44]

Hi all - not sure if this would be better directed at a music electronics forum - but I'll give it a go here.

tldr; power section working but no sound out of the pre-amp

So Fender Yale Reverb - just stopped working - don't use it a lot just a spare amp for jams and stuff. Nicely made btw. I have the schematic - the amp is alive from the power stage onwards - the power-amp in jack works. The pre-amp out gives nothing - there is faint healthy sounding hiss and all 3 volume pots seem to work - volume, gain , master all seem to defeat the faint background hiss. So basically there is no pre-amp signal it seems. Checked/cleaned input jack. Touching the pins of the first opamps with a DMM does not give a thing - no pops finding their way through to the power section. All the power rails check out - 15 / 24 / 37V. There seems to be power everywhere just no life. So , my competence level is I can solder and not electrocute myself and use a DMM , I am thinking someone overloaded and blew the first opamp? One - thing - the tone pots were giving strange resistance readings when I took out the board - like 0 - 18k then down to 12k for a 50k pot as I turned - I suspect dirty pots but could they interfere with the signal path?

Sorry for the long read I've added a tldr !

Paul

It was the 4007 chip. Thread of the full repair is over on Music electronics forum thanks all !