Fender Deville 2x12

[ReginaldBisquet]

A friend of mine brought over his dead Fender Deville 2x12. He said the amp no longer powers up... not even the bulb lights up. He loved this amp and wants it repaired, but his budget is $200.

After doing some trouble shooting, I narrowed the issue down to the thermister (also called an inrush limiter) located at TH-1. I also noticed that two capacitors (C40 and C41) were very wobbly.... like a loose teeth. Other than that, the board looks good. Even still has the original grid resisters which (I am told) burn out quickly.

Question: anyone out there experience a bad thermister on these amps?

Also - his master volume knob is busted... it it keeps spinning round and round. Probably from stripped while getting beat up on the road.

And while I have it open - I was thinking of changing out some caps and resistors as per DIYGuitarist.com's recommendations.

So here's what I have on the shopping list:

Watts Tube Audio
C23 1.5uf --> .022/400v (SOZO)
C26 0.1uf --> .047uf/630v (Mallory 150)
C27 same as above
R12 130k --> 82k/1 watt
C40 1000uf/35 volt --> same (Sprague)
C41 1000uf/35 volt --> same (Sprague)
R61 1 watt/470 ohm --> 3 watt / 470 ohm (metal oxide)
R62 same as above


Darren Riley
R26 Master Volume (Fender Part # 0037600) 100K B (Darren highly recommended NOT installing an audio pot)
TH1 10 ohm / 4 amp C60-11
Tube stabilizer foamy thing (he lost his long ago)


Antique Electronic Supply
TAD 12AX7 (x3)
TAD 6L6 WGC (x2)

 

[TweeDLX]

Removing and replacing the boards on these amps can be very tricky. It's easy (I know from experience) to break the crappy ribbon connectors that connect them together. Care and caution is advised.

 

[DT7]

Keep in view the old addage,"If it isn't broken, don't fix it." If your friend liked the way it sounded, don't go making a bunch of mods to it...or replacing tubes, for that matter. Just fix what's broken.

 

[900z1]

Removing and replacing the boards on these amps can be very tricky. It's easy (I know from experience) to break the crappy ribbon connectors that connect them together. Care and caution is advised.

+1 also watch out for the orange caps on the daughter board that holds the tubes, they are in the way and can break also. I've had problems with both them and the ribbon connectors

 

[ReginaldBisquet]

I found out the hard way just how difficult it is to remove this board. But it's out and ready for work.

The amp came to me with no tubes at all - so he'll need some anyway. And yeah, I am hesitant to make additional changes if he's already happy with the amp. I would really like to switch out R61 and R62 to a slightly higher wattage resistor... just to give the circuit a little more safety.

That thermister... I'm still curious if anyone has replaced one.

 

[jay42]

That thermistor... I'm still curious if anyone has replaced one.

Replace it with a 20ga jumper if it's bad.

 

[ReginaldBisquet]

Oh really? Why? Doesn't the thermister provide a useful function with the amp's circuit?

 

[Ronsonic]

Oh really? Why? Doesn't the thermister provide a useful function with the amp's circuit?

It does, but nothing serious. It does reduce nuisance fuse blows and makes life a little easier on the power switch.

On some products bypassing those is standard practice.

Replace it to do it right, or bypass it to get the thing running.

 

[ReginaldBisquet]

Okay - all parts installed. Problem fixed! Plus - the amp really comes alive now. I installed a 12AT7 in V1 to bring down the gain a bit as he likes to play loud and somewhat clean.

Amp sounds incredible. Owner is also very very very happy.