Epson PX8 Ram Disk stuck at start

[inakito]

Hi everybody.
My PX8 works well when the RAM Disk is not installed. However, when Ram Disk 64K is plugged in, the screen gets stuck.
There are two versions: sometimes I can only see the cursor blinking at the left top row, other times I can see "59.5KB CP/M 2.22 B" and then the cursor blinking.
In both cases, the keyboard does not respond at all.

Batteries look good (I have replaced both the PX8 and Ram Disk batteries).
Without the RAM Disk plugged in, the PX8 works well, I can see the main PX8 menu and enter Basic interpreter and CP/M commands.

I have tried to reset the PX8 by pressing the reset button and, at the same time, pressing shift+GRPH. When Ram disk is not installed I see the text "Intializing..." but there is no different behavior when ram disk is installed.

Is there anything I am missing perhaps?

Regards.
L.

 

[Fezzler]

Sometimes you have to explicitly format the RAM Disk before it will work. Could be the RAM Disk is bad. Or perhaps a driver chip or RAM module. Also, it could be a corroded or oxidized contact on the cable connector. I would suggest 1) Deoxit on the connector. Make sure the cable is good. 2) See if there is an init program for the drive. 3) Check the voltages are correct on the board. A new battery may not mean it works. That's all I can think of.

 

[spiderx]

If the batteries are good, but the ram disk isn't working, you might have some bad components in the ram disk. It's 40 years old, so well past the capacitor lifetime. Check caps, resistors, etc - verify the test points get the proper voltages.