Back in the old days, we had one of these Macintosh Computers in class room. I have one. But it failed to boot showing a broken Mac icon after booting after a few minutes of usage. So I though to give it a try repairing it! And it worked. See me playing some games like TETRIS at the end.
The back case reads:
Macintosh Classic
Apple Computer, Inc.
Cupertino, California
Assembled in Ireland
Model Number: M0420
220-240V~
50-60Hz
0.5A
SERIAL NUMBER Q
[Barcode]
*CK1090AND11*
Keyboard / Mouse (5 Pin)
External Floppydisk
External Harddrive
Printer (8 Pin)
Modem (8 Pin)
Loudspeaker (3,5 mm Klinke)
The main board PCB reads:
APPLE COMPUTER INC. 820-0390-A (C) 1990
.RU T-M 15-V-0 11 N
Yes, I'm wearing the ESD Wrist Strap connected to main-earth. I also used kapton tape to protect other parts.
After repaired the RAM memory (reflow), it seems to work fine.
This is it, the RAM with extension.
It reads, APPLE COMPUTER INC. (C) 1990.
Memory RAM extension slot showing on the right side.
This is where the RAM memory plugs in.
Contact pins on the RAM - some are bad, oxidized or even "eaten" away, blank cooper showing below.
This should made good contact again.
SIMM installed or not? You have to setup it manually with a jumper switch:
It was easier to open the screws hidden in the top handle just with a simple small flat head screw-driver.