IbanezTS9 Led does not turn off

Started by Iffy Jiffy, December 13, 2021, 05:50:04 PM

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Iffy Jiffy

Hi everyone, I have an Ibanez TS9 that works but the LED remains on when I turn the pedal on and off. I have read that there is a transistor that controls the LED and I suspect that may be faulty. I looked at a schematic and I think that Q7 is the transistor responsible for the LED. The PCB on these pedals do not have any markings for the locations of the components. Can anyone direct me to the location of this transistor or if I am wrong about Q7 being the source of my problem, which transistor should I look for and its location.

antonis

You can trace it by starting from point A (LED Cathode & R31 upper leg) going to point B (R31 lower leg & D7 Zener Cathode) ending up to point C (D7 Zener Anode & Q7 Collector)..



P.S.
Before you replace the possible shorted Q7, check for defective R27..
(a value much lower than 56k could force Q7 permanently ON..)
Additionally, check for shorted D7 by measuring voltage difference between its Cathode & Anode (about 4.7V)..

"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Iffy Jiffy

 Hi, thanks for the information. I will focus in that area and let you know how it goes.

Iffy Jiffy

Ok I got the problem solved. It appears that the previous owner went inside for some reason and bridged the transistor with solder that is responsible for controlling the LED.  Somehow, I was not looking for that and overlooked it. Always something new to learn. Thanks again for all assistance.