This article is a documentation of the repairs i had to do on three Korg Poly-61s i got a while ago. As they really needed a lot of work, i split up the repair in several articles. Some of them are general enough and don't just work for the Poly-61. So they have more generic names. Before diving deep into debugging and adjustment of the electronics, you might need to check/repair the following issues. Before starting, please fully read at least this first page of this article to find your right way for the repair.
A very common problem is a leaking battery. This is not just common for the Poly-61, but also for lots of other electronic devices, especially from the 1980s. If they have to store data (a feature that programmable synthesizers usually have), this was done with battery-backed RAM those days. The batteries were either lithium cells, which just need to be replaced from time to time, or they were rechargable batteries, usually NiCd types. Those batteries start leaking when getting old, and the battery acid can be very harmful to all the metallic materials around it - especially the traces on your PCBs. So check how to fix the damage created by BatteryLeakage.
The battery acid doesn't just know how to destroy the direct environment, it also knows how to travel through wires to damage connectors or even other boards. So it might be a good idea to check the quality of your connectors using the description on the DamagedConnectors page.
Another common problem exists with a malfunctioning keyboard. If you have problems with the keyboard, you can read KeyboardRepair first. But i want to mention that the keyboard itself is not the only potential problem if the keyboard action doesn't work properly. There might also be problems in the electronics. If your malfunctioning keys work if you push them really hard, you have a keyboard problem. If you have at least 5 keys which are completely dead, you might need a deeper analysis of the keyboard scanner logic, which is described on the next page among the assigner functionality.
The following text assumes that you find all the boards you need to find. This also applies to the BatteryLeakage document. To get known to the guts of your Poly-61, you should read Korg Poly-61 Boards. If you don't want to touch the electronics, it's just a help on how to find out what model you have and where every board can be found and has to go when reassembling the unit. For the following text, it is necessary to know the spots where you need some measurements.
So after having a look at the documents mentioned above, continue on the next page to learn how the Poly-61 works and how to debug it.
page: 1/7
A very common problem is a leaking battery. This is not just common for the Poly-61, but also for lots of other electronic devices, especially from the 1980s. If they have to store data (a feature that programmable synthesizers usually have), this was done with battery-backed RAM those days. The batteries were either lithium cells, which just need to be replaced from time to time, or they were rechargable batteries, usually NiCd types. Those batteries start leaking when getting old, and the battery acid can be very harmful to all the metallic materials around it - especially the traces on your PCBs. So check how to fix the damage created by BatteryLeakage.
The battery acid doesn't just know how to destroy the direct environment, it also knows how to travel through wires to damage connectors or even other boards. So it might be a good idea to check the quality of your connectors using the description on the DamagedConnectors page.
Another common problem exists with a malfunctioning keyboard. If you have problems with the keyboard, you can read KeyboardRepair first. But i want to mention that the keyboard itself is not the only potential problem if the keyboard action doesn't work properly. There might also be problems in the electronics. If your malfunctioning keys work if you push them really hard, you have a keyboard problem. If you have at least 5 keys which are completely dead, you might need a deeper analysis of the keyboard scanner logic, which is described on the next page among the assigner functionality.
The following text assumes that you find all the boards you need to find. This also applies to the BatteryLeakage document. To get known to the guts of your Poly-61, you should read Korg Poly-61 Boards. If you don't want to touch the electronics, it's just a help on how to find out what model you have and where every board can be found and has to go when reassembling the unit. For the following text, it is necessary to know the spots where you need some measurements.
So after having a look at the documents mentioned above, continue on the next page to learn how the Poly-61 works and how to debug it.
page: 1/7
Page last modified on Thursday 08 of January, 2009 18:29:09 CET
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