freestompboxes.org

Hello!

I am trying to repair an Ibanez SD9 with a switching problem. I have built A LOT of pedals but I have never messed with FET switching. I'm attaching a schematic of the pedal. I replaced the switch thinking that was the problem and it was not. The pedal will switch if I touch the red/white wire to ground but I have to hold it on there for a second or two before it happens. Is it possible that a FET is just reacting too slow and needs to be replaced? The momentary switch is of course a really quick connect/disconnect so it's not doing the trick. If I desolder the red/white wire and touch it to the black wire on the other side of the switch for a second or two the pedal will switch on/off.

Ideas?

Does the LED switches on and off quickly or also slowly?

If it's also slow I think there is no problem with the FETs but with the flip-flop.

Have you inspected the components and tracks carefully? I found a similar erratic behaviour in a TS and the only problem was a shortcircuit between two components leads because they were bended...

the flip flop is where the problem lies
First off - increase the value of the 1000pf capacitor at the bottom right of your circuit drawing - try 10n - 100n.
If that does not work, next, replace the two 1000pf capacitors above it.
If that does not work - replace the custom (CR1 and CR2) networks.
If that still has not fixed your switching problem, then replace the two flip flop transistors.
Hope this helps
Good Luck
bajaman