true bypassing Ibanez 10 series

[jdps150]

I'm trying to true bypassing an Ibanez Fat Cat TC10 & can't find the trannie to get rid of the bypass.
On the 5 series, you just pull either TR2 or Q1. I've pulled each trannie (1 at a time) & can't locate it.
Just need to have it stay 'on'.

TIA

Joe

[Mark Hammer]

Choruses, flangers and phasers can usually be "bypassed" with a single transistor since all you need to do is lift the modulated single out of the signal path.  For distortions, there are generally two transistors involved since the bypass circuitry will need to function like a SPDT switch.

I don't know the specific transistors involved, but they WILL be FETs and they will be Japanese, so that means you look for something with a K or a J in it, such as a J113 or K30A.

BUT, BUT, BUT......

Since the Fat Cat is essentially a Rat variation, there is actually an FET that is part of the audio circuitry and not part of the switching.  It is wedged between the tone control and the volume control.  The drawing found on either Robin Tomtlund's site or Stellan Lehrberg's identifies that FET as a K118 or BF245 though I'm not sure if that is accurate or simply a reasonable sub.  The K30A is frequently used for bypass switching, though.

[jdps150]

Found it.
Amazing what a nite of sleep will do.
It's Q3, & you need to jumper where the middle & 1 of the outside legs were.

Thanks!
Joe

[Mark Hammer]

Whoa, you may need one more night of sleep!

It is highly unlikely that switching of the Fat Cat will involve only ONE FET.  So when you say you found "it", do you mean the FET that buffers the volume control from the tone control, or do you mean the FET you believe to be responsible for switching?  You will need to bypass a pair of FETs if your goal is to leave the pedal permanently on so you can use a mechanical switch instead of FETs.

[jdps150]

>>the FET you believe to be responsible for switching?
Hmm. Pretty sure that's the one.

Well, I've got it so it stays on all the time.
I pulled the power a few times, shorted the momentary circuit, & removed the input cord- stayed on.

[Mark Hammer]

Okay, I'll restate.

You only need one FET to keep the distortion signal engaged all the time.  You need two FETs to turn the straight signal off and another to turn the distortion on.  Assuming the indicator LED goes on and off even though the fuzz *signal* stays on always, you should probably notice that when your LED goes off AND you turn down the fuss a bit, you should hear some straight signal.  Yes?  No?

[jdps150]

Don't know.
Right now it's all apart waiting on pots & sruff from smallbear.
Should have em in a week or so.

Thanks for your help Mark!