Repairing an old Tokai TDL-1 (Delay pedal)

[EliogabaluS]

Hi guys, I'm trying to fix my friend's pedal and maybe you can help me out. The switch system doesn't work and there's no dry signal coming out. I've checked the voltages in the ICs and transistors, so I guess the power supply is fine.

You can find the schematic here: https://www.diystompboxes.com/pedals/tokaidly.gif

Thanks you!

[Fender3D]

There's just 1 op-amp wich serves dry signal, one half feeds signal to the whole path dry and wet and the other half mixes dry and wet.... so it's really odd you don't get JUST the dry signal... unless you got brocken track(s) or wire(s).
Follow the (white) signal... just don't fall in the hole

Happy Easter BTW

[EliogabaluS]

Thanks Fender3D! I followed the signal from the opamp's output. I don't have an oscilloscope at the moment, but sounds really low. Any idea why the switch doesn't work? maybe one of the transistors is gone?

Happy easter mate!
Cris

[Fender3D]

It may be 1 transistor, shorted 10nF in parallel with the switch, led or zener too...
...but I wouldn't focus on switching, because it simply shut wet signal, when "bypassed", and your issue is on dry signal.

You'd better check for signal in this order:
input jack - input buffer out (1uF cap after the transistor) - 1st op-amp output.
Here (1st op-amp output) signal goes to compressor then to BBD AND to output mixer.

If you have signal @ output jack, then output mixer is working, then the issue (unless 47k resistor, PCB tracks or jumpers or wires are faulty/broken) is somewhere else.

Post pins voltage.