TS-9 Bypass Issue (Not a True Bypass Question)

[Stratomaster]

I have a TS-9 that intermittently fails to come on when the switch is toggled, and the switch is not the issue.  I don't know what the problem is other than possibly bad switching transistors.  What is a good readily available substitute for the K30A used in the TS-9?  Do you guys have any other ideas what could be wrong?

When plugged in the pedal is in bypass mode it passes signal just fine--but will not come on when the pedal is actuated.  Any help would be greatly appreciated.  Thanks!

-OMJ

[Gus]

How do you know it is not the switch?  Did you check it? does the LED flicker at all when you press the switch

  Check the flip flop section of the circuit when you momentarily close the switch the outputs of the flip flop changes (collectors of the NPN transistors)You can check that with a meter set to DC volts.  The collectors are what drives the switching fets.  There is a third NPN for the LED

5 NPN 2SC1815, Two EF buffers, Two for the flip flop, One for the LED.

  You need to find a factory schematic or one that has the parts marked and match the PCB if you don't want to trace the circuit.

 

[Stratomaster]

I not only checked but replaced the switch and the switching FETs (I had some left over from a TS-9 I true-bypassed a while back).  I have a schematic and do not mind tracing the circuit.  Interestingly enough, changing the switching FETs seemed to have made it such that the pedal will function normally for a while then quit switching the effect on.  During the normal function the LED dims quite rapidly.  I have a feeling there's a bad cap somewhere in the switching circuit.  Any ideas?

-OMJ

[Gus]

"any Ideas"   yes I posted check the flip flop


Check the input RC off the switch.  Then check the collectors of the flip flop one should be on the other off check with a voltmeter.