Oldest DOD FX55 Distortion I've ever repaired !

vid1900

Most Honored Senior Member
Nov 25, 2016
9,492
Yemen
Guy brought in a FX55 that has the super old rubber footswitch cover (rather than the latter plastic molded switch).


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vid1900

Most Honored Senior Member
Nov 25, 2016
9,492
Yemen
Serial number FX103773, so I assume it's within the first ~3000 pedals that DOD ever built in America. (I seem to remember reading that they started with serial 101000)


Note that "distortion will be present when battery is depleted" (or even if the battery is brand new)
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vid1900

Most Honored Senior Member
Nov 25, 2016
9,492
Yemen
Guts date it to 1982. The production date sticker inside only says "22" with the month and year missing for some reason.

Super clean, I was the first person to service it in 37 years.

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vid1900

Most Honored Senior Member
Nov 25, 2016
9,492
Yemen
Jay asked me in an email "What was wrong with it?"

I guess that would be a natural question, lol.

1. The 9v battery clip had disintegrated (probably too many corroded batteries over 40 years) . That got replaced with a heavy duty plastic cap one.

2. The pedal would just "fart" rather than have a sustained distortion.

Scope-ing it out, one of the electrolytic caps was "open".

I did not have any bright yellow caps in-house, and installing a modern, smaller, black cap would look like it was obviously repaired.

I installed a Rubycon on the trace side of the circuit board, leaving the dead, yellow cap up on top.

Sounds insanely gutsy (with the distortion knob set at 11 o'clock).
 
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