Fender Hot Rod DeVille

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Fender Hot Rod DeVille

Postby Alain Benoit » Mon Jul 11, 2011 11:13 pm

Our studio DeVille blew a fuse a few weeks ago, I simply replaced it and carried on.
Blew the same fuse again yesterday, time to investigate.

The two Sovtek 5881's looked real old, signs of stress, loose debris in them, possibly put in by the original owner.
A closer look at the 470R grid resistors told a tale, they were heated enough so as to not recognized the colour bands on them anymore.
I replaced them with 2W 2% metal oxide resistors.

Fender has to be one of the cheapest built 'proffessional' amplifier companies in the sense that they seem to be willing to save on component costs at any detriment. For example had they used a 2W grid resistor instead of a 1W one, i probably wouldnt be posting this. At the volumes that they buy, seeing that they use 6L6 for a majority of their amplifiers, they must be getting 470R resistors for near 5¢ each, so what would a 2W one cost them, 7¢?
I also recently serviced a Bassman re-issue that had a loud crackling problem, turns out it was a plate load resistor in the preamp section. Again a 2¢ 1/4w carbon composition resistor that failed. Major PIA to diagnose, access and replace. Also in that amplifier all the octal sockets got replaced cause the tubes kept falling loose.

First unscrew the output PC board's stand offs from the chassis.
Image

Old 1W resistor.
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New 2W resistor.
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Alain Benoit
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