Re: Fixing the C900 power supply

From: Michał Pleban <>
Date: Sat, 23 May 2015 16:35:02 +0200
Message-ID: <>

As I turned my C900 on today, the power supply has been clicking for
some time and then died completely again.

After I re-connected the PSU from a 720, the graphic card does not
produce the picture, and the serial port does not work. Apart from that
the computer works OK (I can see the disk activity, and then after it
boots I can type commands blindly and I see that the disk drive goes
alive, so the Coherent system is executing the commands), so I assume
that it is something simple with the voltage - the graphic card needs
-5V for its ECL chips and the RS-232 interface needs -12V and these both
do not work, everything that is powered from +5V and +12V is working

Unfortunately I have no more time to devote to fixing this new problem,
so I decided that it's time my C900 found a new home:

Hopefully somebody will be able to make it fully work again :-)


       Message was sent through the cbm-hackers mailing list
Received on 2015-05-23 15:00:06

Archive generated by hypermail 2.2.0.