Dead HP-9825A

Vassilis Prevelakis vp at
Thu Mar 16 02:49:46 CST 2006

I have an HP 9825A with Opt 2 (24K RAM) which does not display the
lazy T symbol on power up (dark display on power on).

I have checked the PSU voltages and they are OK and have carried out
the obvious tests to see if the problem is a dead display ([RESET]
spc [EXECUTE] [RESET] beep [EXECUTE]) but nothing happens.

Oh, the fan works fine, there are lights inside the tape drive slot
and when I press the CAPS key the CAPS-LOCK LED turns on (and goes off if
I press CAPS again).

I would like to remove the second memory board (16K) just to be sure
that its not a prob with it. The manual suggests that a dummy board
was installed in the place of the 2nd memory board. Does that mean
that the machine cannot work with one memory board?

Also will I get a display with the tape board disconnected?



PS I have the 9825A Service manual, but this simply tells you how to 
disassemble the machine. In fact the troubleshooting flowchart essentially
tells me that anything could be at fault.

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