repairing Ibanez/Maxxon SD9 pedal (switching)

[garyk]

I have two (green) Ibanez (Maxxon) SD9 pedals...and both have the same problem:

the switching/bypass isn't working..from memory you can't get it to bypass (ie always on) when switch is activated.

These are obviously using electronic switching methods, anyone suggest how to repair?

thanks
Gary

[Minion]

Well Chances are it might just be the Momentary switch that is Busted....I recently repaired a DOD Distortion pedal that used a Fet and a Momentary switch and it was the actual Switch that had Failed and not the Fet......

I would say test the switch first and if the Swicth turns out to be OK I would then look at replaceing the fet that Controls the On/Off switching.....

I tried to find you a schematic for this pedal but I couldn"t find one but I did read a few threads about problems with the switching on this Pedal at DIYStompboxes.com and it is a common problem.....Another problem is sometimes Switching noise is introduced to the signal when the Pedal is in Off/Bypass mode so it might be better to try to find a schematic and find out how to wire up a true Bypass switch to the pedal to avoid the whole fet switching thing......


Good luck

[garyk]

a schematic is here

http://www.freeinfosociety.com/elect...ew.php?id=1165

but this may not be helpful!

Yes, the actual switch seems ok so needed to discover which fet is to blame...
thanks

Gary

[Minion]

Hi, that schematic will not help you because it has been Modified from the original one so it has a True Bypass switch so the Fet switching isn"t included in that schematic.....

If it is set right now so it is allways on then just take out the switch and put in a real Bypass switch and wire it to bypass....

Good luck

[GeorgK]

Originally posted by garyk
a schematic is here

http://www.freeinfosociety.com/elect...ew.php?id=1165

but this may not be helpful!

Yes, the actual switch seems ok so needed to discover which fet is to blame...
thanks

Gary

Hi Gary,
is the LED on all the time? Or does it go off and distortion stays on?
In the first case, the switching FETs are probably ok and the problem lies in the multivibrator circuit (2 transistor standard FF if i remember right) or the switch supply. The switching circuit basically should be the same as TS_9 etc, these are probably easier to find. Should not be too difficult to fix anyway.

Good luck,
Georg

[garyk]

Georg: thanks, the TS9 schem shows the multi-vib switching which will help locate the fault.

Minion: the SD9 is somewhat collectible these days, so I dont want to mod the pedal.

I have made up a homebrew TS9 and that might be the way to go, or make a homebrew SD9.

Incidentally, I had a JRC4558 in my junkbox, which I tried in the homebrew pedal,
but I found some op amps (4558's) by other manufacturers that sounded better...don't believe the hype!

Thanks
Gary

[zippy]

The trouble is the momentary switch. I have seen this many times with the Tube Screamer.

First you will have to remove the board located under the part you step on. There is a mini pcb that is held on by two screws. You then need to unsolder the switch, which has 4 contacts.

Pay attention to switch orientation on that board as replacement in proper orientation is important.

I have replacements if desired.
Feel free to email me.


Zippy