Hi Ken,
Ic22 is the microcontroller that basically runs the synthesizer. It has software inside, so you cant simply replace it with a new chip. You would have to get one from another unit. Testing the other circuits without it would be difficult, but not impossible. Since ic22 is tough to replace be careful when probing around it to not short anything to anything else. If ic22 is an NMOS part which it could be, it will get a little warm normally. If it gets hot to the touch, then it may be bad. If you have a scope, check the signals coming out of ic22 to see if they are swinging from 0 to 5 volts. You may see some intermediate levels on the data bus pins when they are floating. Thats ok. With a scope, its pretty easy to find signals that are either floating due to pcb eaten traces, or shorted, due to chip failures.
Good luck.
Bob
Ic22 is the microcontroller that basically runs the synthesizer. It has software inside, so you cant simply replace it with a new chip. You would have to get one from another unit. Testing the other circuits without it would be difficult, but not impossible. Since ic22 is tough to replace be careful when probing around it to not short anything to anything else. If ic22 is an NMOS part which it could be, it will get a little warm normally. If it gets hot to the touch, then it may be bad. If you have a scope, check the signals coming out of ic22 to see if they are swinging from 0 to 5 volts. You may see some intermediate levels on the data bus pins when they are floating. Thats ok. With a scope, its pretty easy to find signals that are either floating due to pcb eaten traces, or shorted, due to chip failures.
Good luck.
Bob
From:
Ken Seastrand <kseastrand@cox.net>;
To: <PolySix@yahoogroups.com>;
Subject: [PolySix] klm-367 Ic 22 testing
Sent: Tue, Feb 11, 2014 8:51:20 PM
To: <PolySix@yahoogroups.com>;
Subject: [PolySix] klm-367 Ic 22 testing
Sent: Tue, Feb 11, 2014 8:51:20 PM
Hi to all I was wondering if anybody has pin out or
data sheet for the ic 22 or info about testing the board with the chip out. mine
gets warm after a minute or so and also the leds seem to work randomly I already
found a bad ic 31 and replaced it as well as the batt/trace
problems.
thanks
Ken
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