George Dennis - GD55 Overdrive Wah Wah

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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modman
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Post by modman »

The pedal belongs to a friend. There is a burnt out resistor connecting the input to the biggest filter cap, leading up to the first IC: CD4093. The lettering being hardly readable, I suspect heat damage on this IC as well.
The biggest problem is that I do not see a way of getting the pcb out: pcb mounted input jack (but the wrong, poke-through type) and no access to desolder them. I looked at a number of other GD pedals, but this one seems to be the only one that's constructed in this way... I next step would be to take apart the footpedal and try and access the input jack solder points from the top. I must be missing something here...

Other ICs are CD4013, CD4053, TL074 and NE5532

The pedal is discontinued: http://www.georgedennis.eu/pages/fxpedals.htm


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strato56
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Post by strato56 »

If you remove the pots and DC-jack, isn't it possible then to flip over the pcb 180° ?

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modman
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Post by modman »

strato56 wrote: 05 Jul 2021, 18:27 If you remove the pots and DC-jack, isn't it possible then to flip over the pcb 180° ?
I didn't go this path because I was sure I wouldn't be able to tilt it even 90°. But tried it now and can lift the board to a 30° or something, which is still enough to be able to replace the burnt out resistor.

I am really thinking it's the 10Ω resistor in this switching scheme from another GD pedal:
Screen Shot 2021-07-06 at 14.37.11.png
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Post by modman »

Just an update: I was able to lift the board just enough to reach the solder pads and replace the 10R... after doing so, the pedal returned to the realm of the living...
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