Nice guy, indeed.
Two things:
first, I've encountered many old 367 boards that were incapable of D/A
calibration (as specified in the service documents) that still worked
fine -- this is probably not an issue.
Second -- regarding the MG bleedthrough...
I've encountered this on many battery-damaged boards; it has to do with
damaged traces bleeding through to each other.
A fix I've found that works 99% of the time: cut the trace on the
bottom of the board at CN06-2, and also the trace that goes to R9 (near
CN05). Cutting the trace at both ends eliminates any possibility of the
mod signal being affected by adjacent traces. The mod bleedthrough
should disappear. Now solder a jumper between CN06-2 and the end of R9,
and hopefully the mod function will work, without distortion or other
problems.
~GMM
Mike wrote:
>
>
> Don Backshall solved all of my PolySix issues and did it for basically
> a handshake. Furthermore, he mailed my KLM-367 board back to me in
> good faith before my PayPal payment even cleared!!! I sent him as much
> extra money as I could because he really deserved it. Here's the
> correspondence bleow:
>
> If the e-mail below can't restore your faith in blind internet
> transactions, I don't know what will.
>
> (Don's Response October 6)
>
> Okay, the boards are on their way back. Priority Mail with delivery
> conf # 03103490000077720492.
> Still three problems that I am aware of:
> 1) D/A calibration - Can't get the right lights to come on, but seems
> to be in spec anyway.
> 2) MG leak - I'm assuming this is caused by some crud between pin 1
> and 2 on the bottom of CN06 header. I know these are a pain to remove,
> but I think it needs to be done. Sounds really bad when it's cold.
> Gets a little better when it warms up.
> 3) MG delay - Known problem with 2N3904 in Q5 position. Using the
> (2SC945) transistor from the old board seems to fix this, but the pins
> are different. You can compare what's connected to what between old
> and new boards to see what pin goes where. One of my old boards had a
> 2SC2785.
>
> $8.60 postage
> $1.60 fuses
> $0.15 capacitor
> -----------------------
> $10.35 grand total - You can send it to this Paypal acct
> backshall1@bellsouth.net <mailto:backshall1%40bellsouth.net>
>
> I'm pretty sure you can get this board sounding just like it should,
> even if you can't get the right calibration lights to come on.
> Have fun,
> Don Backshall
>
> _______________________________
>
> (my response to him solving my problems October 05)
>
> That's great!! It looks like I'm a decimal doofus! Ha Ha. What's the
> bill? I can send you a PayPal payment today or tomorrow. I'll praise
> your expertise on the Korg PolySix forum too if you're intersted.
>
> Thanks again,
>
> -Mike
>
>
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