I am working on restoring a Mac Plus that seems to have several issues.
Initially it would not power on. I resolved this by replacing the 2.5A fuse and also the RIFA caps, which had been blown. At this point the computer would chime but nothing else. However, if I tapped the analog board near the center, I could see screen activity.
I reflowed the analog board where the connectors are (“J”) and after that the screen came to life. I could see the floppy icon with a blinking question mark. However the drive itself wasn’t working. I took out the floppy drive and cleaned it up, replaced a broken gear, and applied new lubrication.
This is where I get lost: I plug the floppy drive back in, power up the machine, and I get the following:
- No startup chime
- CRT is powered and I can see horizontal raster lines, but no actual video
Reseating RAM and ROM chips has no effect. I have not been able to get it out of this state. I don’t really understand what removing the floppy drive could’ve done…but perhaps it’s just bad luck and something else has broken while I worked on it.
If anyone has suggestions for what to focus on, I’d be grateful! I’ve checked voltages from the external floppy port pins, and it seems the analog board is providing the proper voltages.
Initially it would not power on. I resolved this by replacing the 2.5A fuse and also the RIFA caps, which had been blown. At this point the computer would chime but nothing else. However, if I tapped the analog board near the center, I could see screen activity.
I reflowed the analog board where the connectors are (“J”) and after that the screen came to life. I could see the floppy icon with a blinking question mark. However the drive itself wasn’t working. I took out the floppy drive and cleaned it up, replaced a broken gear, and applied new lubrication.
This is where I get lost: I plug the floppy drive back in, power up the machine, and I get the following:
- No startup chime
- CRT is powered and I can see horizontal raster lines, but no actual video
Reseating RAM and ROM chips has no effect. I have not been able to get it out of this state. I don’t really understand what removing the floppy drive could’ve done…but perhaps it’s just bad luck and something else has broken while I worked on it.
If anyone has suggestions for what to focus on, I’d be grateful! I’ve checked voltages from the external floppy port pins, and it seems the analog board is providing the proper voltages.
