Re: Fixing the C900 power supply

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Sat, 23 May 2015 18:42:13 +0200 Message-ID: <5560ADE5.5040903@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 05/23/2015 04:35 PM, Michał Pleban wrote:
> Hello!
>
> 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
> correctly.

Did you check the PSU for any capacitors with the 'ROE' logo on them? 
Those tend to mutate from capacitor to short circuit.

  Gerrit

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