I was very glad recieving the service manal from You. Additionaly very fast. Extremaly nice servicing. Thanks very mach! Now my GX-220 working better, than it was made. Alexander from Moscow, Russia/
Sweet! I won the item on eBay and couldn't adjust the geometry or even keep a steady picure. This guide has the full schematics (not available anywhere else as far as I could tell), and was a bargain for the wealth of knowledge it contains. I hooked it up to my testing equipment, tweaked a few potentiometers and got it playing videogames in no time. Thanks!
Great Manual! It contains all the wiring schematics and mechanical exploded views that are essential for service and repair. I was surprised I even found this for such an old machine. Only wish I knew of this site many years ago.
Great manual very clear copied. You are making an incredible job. I appreciate a lot the rapidity and your efficiency. Thanks a lot
Text excerpt from page 138 (click to view)
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Audio
A
No sound from the speakers Yes Are the SP cables properly connected? Yes Is sound muting set? Yes Is the volume set to 0? No Raise the volume then check again. No Connect the SP cables properly then check again.
No
Cancel muting then check again.
B
Yes AUDIO AMP Assy 2 3 Is a signal output from IC5003 Yes on the AUDIO AMP Assy? No AUDIO AMP Assy 1 Has the signal arrived at IC5003 on the AUDIO AMP Assy? No Yes Check around IC5003. Check the connection between the AUDIO AMP Assy and the SP Terminal Assy.
A
AV I/O Assy =
C
Is a signal output from IC7603 Yes on the AV I/O Assy? No Has the signal arrived at IC7603 on the AV I/O Assy? No Yes
Check around IC7605, IC7606, and IC7607 on the AV I/O Assy, and the connection between the AV I/O Assy and AUDIO AMP Assy. Is communication between IC7603 and the microcomputer OK? Yes Check around the IC7603. No
Check the communication line.
AV I/O Assy Is a signal output from IC7601 No on the AV I/O Assy? Yes Is IC7601 on the AV I/O Assy properly controlled by the microcomputer? Yes No Check the communication between IC7601 and IC7603.
D
Check the control line from the microcomputer.
Check the communication between each input terminal and IC7601.
