Black Cat Moan problems - help with debugging?

[grolschie]

Hi guys,

I scored a Black Cat Moan wah pedal....cheap. Looks absolutely mint. The guy bought it new and it never worked. Basically sounds comes out of it when in bypass mode, but kicking on any of the effects (wah, moan, etc) and the sound is gone, no LEDs nothing except a bad hum. Tried 9vDC adapter and battery.

I opened her up and cannot see any dodgy solders. There is a multi-wire cable connecting two circuit boards. If I disconnect that, there is no sound even when bypassed - so I guess it maybe not true bypass.

I notice when I plug it into my daisy chain with my ROG Eighteen, when I kick on the wah, my Eighteen stops working, so something to do with the 9v power in the wah is screwed. Hence the hum.

It seems that a few folk have had issues of a similar nature (pedal stopped working) with the Black Cat. Any ideas on where to start the debugging? Or should I send it into get a pro repair. Thanks in advance.

Cheers,
grol

[jonathan perez]

start with a DMM.

"pro" doesnt mean anything to us, unless it involves a tube amp. 

[Mihkel]

It is true bypass, as i understand it, the two extra switches are DPDTs also to switch the moan effect on in series with the wah, so if you disconnect one of the circuit boards, you also disconnect the bypassed signal route.

I'm tracing the schematic right now but I can't say that it's going real fast.

No LED and hum. I'd say the 9VDC is shorted somehow. Check for a short between +9V and ground.

[grolschie]

Hi. Thanks for that.

I have discovered that the pedal now works (as a wah - nothing else) when I remove the secondary board. Lights come on. Plugging secondary board in kills the power on the pedal. I have looked at both boards and can see nothing blaringly obvious. I have received the schematic from Rocktron, they were quite willing to email it.

Funny thing is when wah is off, no bypass signal (as previously stated), but can hear a wah wah sound if I wiggle the pedal. Maybe it's buffered bypass and this will disappear when secondary board is fixed and attached.

Not sure of how to start testing with a multi-meter. Any clues? Do I find the path where the 9v goes and stick one probe of my DMM on the ground or something? Some of the solders seem close together, but still a tiny gap.

I got a better range out of the wah by adjusting the position of the teeth on the pot, but still not quite enough for me yet (but have fun out of movement on the pot). I seem to use the tip of the pedal far more than the heel. I am sure there is some tweak that can be added i.e. resistor somewhere?

The pot is also scratchy, so I should also figure out if it can be cleaned.

[Mihkel]

Uhh, I think I'm out of my league here to try and help you know.

But I have one question, when you got it, if you set the pedal to the treble-most position, was the pot at the very end of its rotation? Mine's like that and if you switch it, it pushes the pot and puts it under pressure. Not the best thing for it, I imagine. And  I was also surprised to find a regular Alpha pot there.

[grolschie]

My pot was almost, but not quite at the end. It is now though. It seem like it just needs 10-15% more, I wonder if a resister somewhere would shift the entire range of the pot up.