Digitech WH-1 problem

[stevenrb718]

No other ideas?

[g1]

No other ideas?

Can you post some pictures showing the IC's and their numbers?

[stevenrb718]

Can you post some pictures showing the IC's and their numbers?

I never found any other examples of a WH-1 not working but having the LED not function. Other blogs of a faulty pedal always seem to have LED function at least.

[g1]

I never found any other examples of a WH-1 not working but having the LED not function.

The LED is supposed to indicate effect on/bypass. On the schematic in the XP package, pg.3, you can see it off pin 7 of U20, the 80C31 CPU. I'm not sure why they don't show the VCC pin 40 of the CPU, but there should be 5V. Also check the reset line at pin 9, bad cap there might lock it up.

[stevenrb718]

The LED is supposed to indicate effect on/bypass. On the schematic in the XP package, pg.3, you can see it off pin 7 of U20, the 80C31 CPU. I'm not sure why they don't show the VCC pin 40 of the CPU, but there should be 5V. Also check the reset line at pin 9, bad cap there might lock it up.

Earlier I did trace the LED back to the 80C31, along with the grounding switch pin. The voltage was correct, and the switch pulled to ground properly. I do have 5V at pin 40. Also, the cap on the reset line is A-OK. I'm not sure what I'm supposed to be seeing on the scope at pin 9, but I did randomly plug the pedal in with the cap removed and the LED now locks on. There is also a signal coming through the effect line, but it's a scramled, distorted note.

[stevenrb718]

Further update, I don't know if the 80C31 needs any form of programming, but I randomly swapped it with no change in the pedal behavior.

[stevenrb718]

Bump

[g1]

I'm unclear about what is going on in post #20. The pin 9 reset line provides reset when pin is pulled high. This happens during power up because the cap is low resistance till it charges to 5V. Once it charges, that line (pin9) should be pulled low by the resistor.
With the cap disconnected, that line stays low. You said that with the cap disconnected, the LED came on. To me, that means there is a problem with the reset line.
Do you still have the cap disconnected? You said in that condition it passed signal. Were you able to bypass and was signal clean then?
You mentioned a grounding pin but I don't know what that would be.

[stevenrb718]

I'm unclear about what is going on in post #20. The pin 9 reset line provides reset when pin is pulled high. This happens during power up because the cap is low resistance till it charges to 5V. Once it charges, that line (pin9) should be pulled low by the resistor.
With the cap disconnected, that line stays low. You said that with the cap disconnected, the LED came on. To me, that means there is a problem with the reset line.
Do you still have the cap disconnected? You said in that condition it passed signal. Were you able to bypass and was signal clean then?
You mentioned a grounding pin but I don't know what that would be.

My fault, the ground I was referring to was the switch. I was just saying that the switch does function properly and pulls whichever pin it was on the 80C31 to ground when engaged. With the cap pulled, the LED is on and the effect is distorted and not working. The pedal isn't affected by the encoder or the footswitch. With the cap installed, the LED is out and there's no effect sound whatsoever. Neither cap in/out has the footswitch changing anything.