DOD - FX40B Equalizer  [schematic]

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aloupos
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Post by aloupos »

I'm in the process of repairng this DOD FX-40b eq. Here are the gutshots. When i received it, the offboard wiring had been tampered with. Does anyone have a schem or diagram showing the switching / offboard wiring ? Or, can anyone lend some clues as to how the power is supposed to be supplied?

Anyway, enjoy the gutshots:

Image

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analogguru
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Post by analogguru »

Do you mean something like the file below ?

analogguru
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DOD - FX40-B  Equalizer schematic
DOD - FX40-B Equalizer schematic
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borislavgajic
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Post by borislavgajic »

nice pictures!!! :P

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aloupos
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Post by aloupos »

Thanks AG!

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Chipsgoumerde
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Post by Chipsgoumerde »

Hi,

First message here, I hope it's okay to revive an old thread.

I own one of those. Years ago I needed a 9v battery connector so I unsoldered the one from the FX40b because I wasn't using it at the time and I was in a hurry.
Now I would like to fix it, I don't care for the 9v battery connector because I have a power adaptator.

I don't have much experience with electronics but this is a very simple fix. The input connector for power is now connected to nothing and I have a yellow wire that is hanging. Would someone kindly explain to me how I should connect these?


Will do some picture tonight if it helps.

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TWAlex
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Post by TWAlex »

DOD FX 40B factory schematic :
This is another scheme.
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dod_fx-40b_equalizer_sch.pdf
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DOD-FX40B-EQUALIZER_large.jpg

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TWAlex
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Post by TWAlex »

DOD FX40 Equalizer
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FX40.jpg
FX40.jpg (55.71 KiB) Viewed 3904 times
FX40-front.jpg
FX40-front.jpg (41.02 KiB) Viewed 3904 times

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Chipsgoumerde
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Post by Chipsgoumerde »

Thanks!
However it's hard for me to understand these schematics.
What I've done is I've open another DOD I have (FX57, shitty distortion/delay) to see how it is wired and I repaired the FX40B that way.
And it works.
Cheers guys.

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TWAlex
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Post by TWAlex »

The FX40B Equalizer was a seven-band graphic equalizer. Initially the pedals were grey with red graphics and slider covers. Circa 1992, the cosmetic appearance of the FX40B was revised with brown paint/white graphics and all-plastic slider pots, eliminating the risk of losing a rubber slider cover. In 1998, when all other pedals were revised to the final version casing (in preparation to the made-in-China VFX series), the DOD FX40B remained the same (albeit with new graphics at the top of the pedal), probably to help use up the supply of old casings. ( http://www.americaspedal.net/fx40b/ )


Last version 1999, - factory schematic:
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FX40B factory schematic 1999.pdf
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MilesXC
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Post by MilesXC »

Not liking the bypass on this much, and have a relay bypass board ready to go.

Looking at the schematics above I can see Q1 and Q2 are involved somehow.

Am I right in thinking removing one of these, or maybe D1 or D2 would force the circuit to be always on?

Cheers,
Miles

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Fender3D
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Post by Fender3D »

If you just remove the FETs you got no signal at all...
You must place a jumper shorting their Drain and Source pins.

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Post by MilesXC »

Thank you.
Will see how I get on : )

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Post by MilesXC »

Works a treat.

If anyone else ever does this it's worth noting the J113 pinouts are GDS, not GSD like Google would have you believe.

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