Malekko Spring Chicken - no effect, just hiss

[Snufkinoob]

Snagged one of these on ebay, and it worked fine for a while. I sold it, but the buyer said it wasn't working, and so returned it. It's not producing anything but hissy white noise when the effect is engaged.  It wasn't damaged in transit, the box was completely fine and well packed both ways.

I've done a little homework and it seems this isn't an isolated case with this particular pedal. One suggestion which I think solved the problem for one person was to coat a jack plug with contact cleaner and to repeatedly plug/unplug it in all the jacks. Didn't work for me. I've opened it up to check for bad connections but I can't see anything visibly wrong with the circuit board or wiring anywhere.

Only other things worth mentioning are:

The mix and dwell knobs seemed to have an effect at first. The hiss got louder, and was oscillating with the dwell on full, which is how the reverb usually behaves on higher settings. However, now it's just hiss and turning the knobs does little, if anything.

9v battery gets the same results, as does using different power supplies. I tried a daisy-chain connection with three other pedals (all Boss) but when I plugged in the forth connector to the Chicken, it killed the other pedals dead. No damage, just cut them out, and they wouldn't power up until I removed the plug from the Chicken. No idea if that is an indication of a possible source of the problem?

Any ideas?

[GibsonGM]

Sounds like a possible short in the chicken power supply, to me.   That would cut out your daisy chain.

Any chance the dude who bought it could have used the wrong polarity power supply??

Do you have a digital multimeter? (DMM)     If so, test for continuity between + and - with a plug plugged into the input jack (to switch the effect on - but don't YOU apply any power during this test), see if you get 'beep' or a low resistance reading across the battery snap.

That is step 1...

[Snufkinoob]

There is some continuity. It's reading 0.300 in the 2k range across + and _ of both the battery snap and the adaptor connector. Forgot to mention the LED works, if that's an indication of anything.

No idea if the guy used an incorrect power supply by accident.

[NFX]

If we knew if this circuit had reverse polarity protection we could eliminate that theory, a schematic would be good but I doubt there isn't one about. I would think there would be a regulator in the circuit somewhere(probably a 5v) and I suspect it has been damaged by wrong power supply.

[GibsonGM]

Yes....if you can find and post a link to schematic, that'd help a lot!   And, a couple of pics of your PC board to go along with it, both front and back...maybe we can see either a regulator or a diode for reverse protection.

Welcome to the forum, by the way.  Give it (and us) some time, and we'll figure out what's going on! 

[Snufkinoob]

Doesn't look like there's any power protection diode. There's a resistor in that protective sheath...

[NFX]

What's that transistor next to the sleeving say on it

[Snufkinoob]

It's just a 2n5088, V readings are:

E 1.37
B 1.49
C 6.38

[GibsonGM]

It's just a 2n5088, V readings are:

E 1.37
B 1.49
C 6.38

There should be a diode drop between  B and E, so this seems to be telling you something.   Exactly what, I'm not sure, haha.  This effect is out of my experience, and no schematic to see how it works.   

I still think it could be reverse-polarity was applied.

[Snufkinoob]

If the wrong polarity was used, would new transistors, IC and belton brick be a possible fix?

[NFX]

If your not in a hurry I can look at it if you posted it to me but it would be the end of December or early January until I can properly look at it

[GibsonGM]

If your not in a hurry I can look at it if you posted it to me but it would be the end of December or early January until I can properly look at it

I'd take him up on that, Snuf!  This kind of circuit  (looks SMD) is really hard to troubleshoot at a distance.  Typical stomp boxes are easier.

Someone with more tech ability can take a lot of measurements quickly and determine (hopefully) what the next step should be.  Going around randomly replacing things often leads to disappointment (does nothing, or the new parts fry...), and can also ruin the unit.  If you don't HAVE to take stuff out, you shouldn't, as you run the risk of overheating parts, ruining solder pads and the like.

[Snufkinoob]

If your not in a hurry I can look at it if you posted it to me but it would be the end of December or early January until I can properly look at it

Pm'd thanks