**help** korg poly 61

Dear Lamster,
Thank you for replying. To answer your questions:

I have the second type P61 I guess: three boards (CPU+voice+aux) not counting the power board. I have cleaned the cpu board (Isoprop, MEK, dist. water, excessive drying) and repaired damaged tracks just by soldering direct connections between the dead points. However, I can measure the gate signal (CN12) at the dead voices, but i don´t know what other signals from the CPU board are required to generate a sound.
I might as well recheck all connections on the CPU board, just to make sure that I did not miss any broken connection. All other functions are working on the unit. Help with drawings would be appreciated, since i don´t have any, but i also could not read any ;)
Kind regards

the cpu board is KLM-475 in mine
 
Last edited:
selector97 said:
Dear Lamster,
Thank you for replying. To answer your questions:

I have the second type P61 I guess: three boards (CPU+voice+aux) not counting the power board. I have cleaned the cpu board (Isoprop, MEK, dist. water, excessive drying) and repaired damaged tracks just by soldering direct connections between the dead points. However, I can measure the gate signal (CN12) at the dead voices, but i don´t know what other signals from the CPU board are required to generate a sound.
I might as well recheck all connections on the CPU board, just to make sure that I did not miss any broken connection. All other functions are working on the unit. Help with drawings would be appreciated, since i don´t have any, but i also could not read any ;)
Kind regards

the cpu board is KLM-475 in mine
Click to expand...

Try here
http://fa.utfs.org/diy/korgpoly61/Korg_Poly-61_ServiceManual.pdf
 
Thank you again for the link, i directly saved it. However, my understanding of these circuits is very very limited, meaning the i cannot extract the information of what the actual purpose of a signal is that is transmitted on a certain connection. I have no background in electronic engineering , but rather one in genetic engineering.

So I definitely need advice where to check and what. I will strictly follow your suggestions and would be glad if someone donates the precious gift of time for help.

kind regards,s97
 
selector97 said:
Thank you again for the link, i directly saved it. However, my understanding of these circuits is very very limited, meaning the i cannot extract the information of what the actual purpose of a signal is that is transmitted on a certain connection. I have no background in electronic engineering , but rather one in genetic engineering.

So I definitely need advice where to check and what. I will strictly follow your suggestions and would be glad if someone donates the precious gift of time for help.

kind regards,s97
Click to expand...

Yeah if I can find my printed circuit diagram with my notes I haven't touched one of these for 4 years.
I was looking back over what I posted indeed CN12 was my issue with loosing voices there are also a couple of ICs 14051 same as 4051 used to multiplex.
These are from that era when Cmos ICs were prone to static damage more so than modern devices that now have internal protection.
If they are screwed you may lose voices fortunately you can buy them pretty easy and cheap.
I would check CN12 the crimps in case they are broken inside the housing and clean up the header I would also check the tracks on the board back for damage.
If you dont have a multimeter invest in a cheap auto ranging one. problems with synthersizer mean you very likely end up needing an oscilloscope once you get to this stage you find that a lot of hair pulling,
late nights and a barrel of coffee is also required.
 
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