Poly 61 Troubleshooting

sensationlive · Post by **sensationlive** » Thu Apr 26, 2018 8:07 pm

Hi. I have had my Poly 61 since 1982 and is in excellent cosmetic shape. I had not used it for many years and when I recently fired it up I would play a note but it sounds like a cluster of notes together. I can switch programs properly and all keys work. The unit has a chord memory feature so I'm wondering if there is something that is triggering it to kick in automatically, stacking 6 random notes by playing only one key.
I really want to make this unit playable again just because it's the first synth I ever bought and am trying to avoid restore costs being 5x the actual value of the unit. Just wondering if anyone has experienced something similar and what was done to resolve it. Also, would you know if Korg authorized service know how to repair the unit given it's age or would you suggest specialists?

rkeytar · Post by **rkeytar** » Fri Jun 01, 2018 7:39 am

Have you checked for battery leakage? damaged traces can cause many deceiving issues. Are the cluster of notes detuned? check how many voice LEDs on the voice board come on when you press 1 key. Oh, and are the clusters occurring anywhere on the keyboard or only specific area?

sensationlive · Post by **sensationlive** » Fri Jun 01, 2018 1:37 pm

Thanks for the head's up. I have just read up about this battery leakage issue and sounds like it could be contributing. I will check out what you suggested. Thanks again

monsterjazzlicks · Post by **monsterjazzlicks** » Thu Jun 07, 2018 5:28 pm

Hi folks,

I fired up my Poly 61 this week and its acting strange in that it played fine for 5 mins, but then half of the notes are not sounding and the other half are completely out of tune! I don't know why this has suddenly occurred? I see (above) rkeytar said that battery leakage can cause a lot of problems, but I think the battery type is not the old prone model?

Everything else on the Korg works fine.

I would be very grateful for any advice if anyone has ever have a Korg Poly 61 which suffered these symptoms?

Many thanks in advance.

Paul

rkeytar · Post by **rkeytar** » Wed Jun 20, 2018 8:08 am

well, if the battery was changed to a coin cell and you know for a fact that it was working well after it was changed. your problem could be cause by a few things, if you haven't gone in there and touched any connectors.

1. bad rubber contact strips (under the keys), I've been had by that one!
2. bad IC1 (assigner) which scans the keyboard, if you have a scope you can check the pulses on it and the surrounding IC's as well.

out of tune;
1. maybe loose wire on CN11 or bad pulse from a D8253 ?

monsterjazzlicks · Post by **monsterjazzlicks** » Wed Jun 20, 2018 12:15 pm

Thanks a lot rkeytar,

I have an electrician coming over to have a look at it over the next couple of months. I will let you know how he gets on after he has investigated it.

It's truly devastating when a vintage synth goes under.

Cheers,

Paul

monsterjazzlicks · Post by **monsterjazzlicks** » Thu Jun 21, 2018 6:49 pm

Hi rkeytar,

I am not sure if you are familiar with these boards from Germany (see LINK)? It may be a last resort option if all else fails.

Ta,

Paul

http://synthronics.de/klm-509a-475b-replacement/

rkeytar · Post by **rkeytar** » Fri Jun 22, 2018 1:53 am

Realistically speaking, those are rather expensive. I've lost patience many times but I've resurrected 2 broken poly-61's so far. You just need to be patient and understand how it works. take it one step at a time.

monsterjazzlicks · Post by **monsterjazzlicks** » Fri Jun 22, 2018 10:06 pm

Hi rkeytar,

I suppose one option - if my Poly-61 is discovered to be in a bad state - is to sell it on eBay 'For Spares'; and then purchase a replacement with the funds gained. There is one currently advertised (with MIDI) but is over 500GBP.

Are you based in the UK, please?

Thanks,

Paul

rkeytar · Post by **rkeytar** » Sun Jun 24, 2018 3:36 am

Hi Paul,

if properly diagnosed and IC1 assigner MCU is found dead then I think you can purchase a replacement IC from a few sources or perhaps online. If D8253 timer IC is bad it would also be easy to replace and are pretty cheap, but without a scope it will be hard to determine. In that case, I suppose you could sell it for parts or as a whole and purchase another one. Perhaps look locally in for sale ads, you might find a less expensive one.
I'm in Canada so I can only advise you via this forum but the final decision is yours.