A friend of mine give me his non-functional tap tempo delay guitar pedal.
The problem with this pedal was that one can hear an annoying clicking sound while playing. Also after trying it for a while it stops working.
The pedal is called La Macchina del Tempo by Fattoria Mendoza, a custom pedal builder here in italy.
Advice: I've never have any pedal from this company. I think the pedal I have has been handled by someone outside the company, or they have build this as a demo pedal, indeed I can not find this pedal on theire actual website. I advice you this cause what I've found in this pedal is not that beauty.
First time I've opened the pedal I've seen a little bit of a mess, wires has not been secured on the case.
I've played this pedal for an hour or so with the back case open. And after a while the pedal stop working, the output led does not blink.
The pedal itself has a couple of boards, the main one is a 1 side PCB with a scratched number, I've searched for it and I've found it's a kit uk-electronic named Kit Digital Delay PT-80 with tap tempo (http://uk-electronic.de/onlineshop/product_info.php?products_id=2326&language=en). The other two are prototype boards that just has some capacitors and a output volume control.
First thing I've checked is the switching regulator, the LTC1044. And that's the guilty. No voltage output from this IC. So I try injecting voltage after it and the pedal start working again. So I've replaced it.
While waiting for the IC to be delivered I've clean up a little bit the PCB. I've soldered a couple of components that where just punched in used pin head. And resolder a couple of wires.
When the IC has been delivered I've checked the pedal, and here I can found the first problem my friend told me about, that it the annoying clicking noise.
I've notice this noise has exactly the same frequency of the tap tempo led. So I've remove the led and I've notice it was the led the root of the problem. Adding a capacitor on the supply line does not solve the issue. So I've added a RC low pass filter on the led line. This will slow down the led light up but has solved the issue.
Now the pedal has been cleaned up and can be used again.
Notes
- read risk disclaimer
- excuse my bad english