Blues Deluxe Power Supply Filter Caps

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ngw
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Location: Tamborine Mountain, Australia

Blues Deluxe Power Supply Filter Caps

Post by ngw »

Have any of you blokes had any problems with faulty Filter Caps in the 16 Volt solid state supply or Bias Supplies of the Blues Deluxe, or other Hot Rod Series Fender amps?

I am replacing the leaky HT filter caps and doing some other work on this amp and I am wondering whether I should replace these other electrolytic caps as well.
They are a bit of a pain to remove and I am always concerned about Fender's flimsy boards and traces, particularly with flush mounted radial caps that I can't clip the leads off.
So far I haven't had any faulty ones in other repairs of these type amps, but this is a mid-'90s amp and I would rather resort to prevention than cure and give the owner reliability.

I would appreciate the advice of other Tech's experience here.
Thanks, Noel.
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xtian
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Re: Blues Deluxe Power Supply Filter Caps

Post by xtian »

I've seen a dozen or more of these amps with switching system failure, bad filter caps, bad input jack connections, etc. With the 15v PSU, it's usually failed solder joints. The recent one that came in was bad, because the PCB was burned to the point of conduction. Even in this state, the owner reported the switching system was still working--amp came in because the filter caps were failing. The 15v circuit's radial caps were bulging from heat damage, but still kicking!
I build and repair tube amps. http://amps.monkeymatic.com
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pompeiisneaks
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Re: Blues Deluxe Power Supply Filter Caps

Post by pompeiisneaks »

yeah I've repaired my own from the original '95 era, and those power resistors for the circuit get way too hot and also often burn up the filter cap just above them. (that and they're the fender super crappy IC ones). It's a pretty common problem. Also common on the Hot Rod Deluxes. I just fixed a buddies and they burned up the traces so that just trying to get them off they came apart, had to put in several bodge wires.

~Phil
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ngw
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Joined: Sun Jul 29, 2012 2:54 am
Location: Tamborine Mountain, Australia

Re: Blues Deluxe Power Supply Filter Caps

Post by ngw »

Thanks for the replies, xtian and Phil.
Sounds like you have been dealing with the same failures that I've seen.
Makes me wonder why Fender keeps using those crap IC caps.
I kept the PCBs from a B.Dlx. repair job that was beyond sensible restoration, due to the power resistor damage and many damaged traces from a lot of repair work.
I keep them as an example to others, of what can happen to these amps; Very poor quality.
I built a new amp for that owner with turret boards, using the original cab, chassis and transformers; it wasn't a B.Dlx any more.

The current job also has some heat damage from the power resistors, but it's not too bad.
I have attached wires to the board that I will connect to 50W chassis mounted resistors - no more burned board.
I haven't had any failed caps in a 16V supply yet and this amp's switching and reverb were also working fine; which is why I asked about the caps.
Maybe I should just replace those 16V supply caps as well, to be sure.

The local luthier just brought me his Blues Jr which has stopped working.
Looks like it's PCB Fender week.
These Fender PCB amps are no fun to work on.

- Noel
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