Broken Little Lanilei and a Suspicion

[gimelvav]

I got a good price on a broken Little Lanilei. It came with no adaptor and of course I have no schematic. I've seen that other people here have looked for the schematic for this and didn't get a response. So, I'm just poking around, checking continuity and checking the individual components in situ. I'm NOT an electronics expert. I have a cursory knowledge of Ohm's law and what the various components do, and I've done lots of soldering of speaker wires and such.

The Little Lanilei is interesting in that the input and output jacks are reversed from most modern pedals. Also, the 9v power adapter is POSITIVE tipped. So, as I was poking around with my multimeter, I THINK I found a shorted diode across two of the connectors on a true bypass relay where an LED is also wired. The problem with the pedal is that it seems to be permanently bypassed. The sound goes through from input to output, but the pedal doesn't engage. It seems to be a problem with the true bypass relay. So, I tested the leads to the relay for continuity, and they seem to be working as expected, but I found what I believe is a shorted diode. I say "believe" because it's soldered onto the relay, and I don't know if possibly something else might cause it to read shorted.

Bottom Line: Is it possible that someone attached the wrong adapter - neg. tip instead of pos. and too much voltage - and shorted the diode across the relay? Is this the kind of damage that might happen? And, if so, how do I determine the value of the diode to replace it with? The resister values are printed on the circuit boards, but this diode is just soldered across the top of the relay. It looks like it might be color coded, but it's small and the colors are difficult for me to see. Since it seems to be shorted, the DMM is just showing 000, so there is no value.

[thermionix]

Don't know the circuit.  It is common for people to fry a diode with wrong-polarity power.  That's usually a protection diode in the power portion of the circuit, but other damage is certainly possible.

Can you post pics?

[gimelvav]

Now that I've had a much better look at it, it looks like someone tried to fix and/or mod the pedal and was not successful. There's lots of sloppy work, and some "Kit" parts in it. Either that, or this was a prototype???

Here's an overall view. Unlike most modern pedals, the input is on the top left and the output is on the top right. Also, the power jack is positive tip and located in the front of the pedal.


Here's a closeup of the power and remote control.


Here's a closeup of the input side of the Accutronics spring tank.


Here's a closeup of the output side of the Accutronics spring tank.


Here's the highly suspicious preamp section. It's missing a resistor for a mic. () I've labeled the wires that lead to the LED which doesn't light up and the suspicious diode that reads 000 (shorted) on my DMM. I think they're attached to a relay (?) for true bypass.


Here's a complete view of the Preamp->Relay(?)->Amp modules wiring.


Here's a closeup of the input jack wiring.


Here's a closeup of the Accutronics input.


Here's a closeup of the suspicious diode.


Here's another closeup of the suspicious preamp.