Mike's PCjr Page

Anyone here have much experience with the Quadram expansions?
My RAM expansion (I think it went up to 256K) went bad sometime in the mid 90s and for the longest time I didn't know what "ERROR A" meant so I carried on with life until a few years ago and found out that it was a RAM issue. Removing my expansion makes the machine successfully boot with 128K but nowadays it doesn't even recognize the expansion deck at all when I have it plugged in.
Anything you all recommend trying?

Meanwhile I'm trying to get my floppy drives to do a darn thing as well. They spin but that's it. I've hooked up a more recent floppy drive to the machine and it loads fine from it, but my original drives don't move at all so they may need their optical sensors cleaned, but I don't know enough about them to accurately diagnose what's wrong.
Any ideas will be appreciated! Thanks!

Generally if you can reduce a RAM expander down to a minimum amount of supported RAM, then that's usually a good troubleshooting step. You likely have a bad RAM chip. Does any other information display apart from the ERROR A?

Nope, just the ERROR A. But now whenever I have it attached, it doesn't seem to detect it or test for the expanded RAM anymore, so either the connector has been damaged or something else has gone kaput.

Do you have joysticks and/or a serial cable connector perchance? You can use the joysticks to enter a manufacturing test mode which should spit out more info to the display/serial port.

I have one joystick, so I'm not sure if I can access the test mode. What exactly do I need to accomplish this?