Topic: Dodgy power supply blew my C128!

[kokapetl]

Everything was working fine and I made the stupid mistake of testing out a C128 power supply with it. The power light went on for a second, then off (it faded off, in case that's relevant). Now, when I turn on my 128 (using a good power supply), the power light stays on but I get a black screen. Any suggestions or ideas?

Replies will be much appreciated!

[Hydrophilic]

Unless you have experience repairing electronic circuits, I suggest you buy another C128 or contact Ray Carlsen.
 
I've seen cases where a deffective commie will blow-up a good power supply, but not the other way around!  Actually about a year ago somebody posted about how they tried wiring up a power supply to their C128, got the wires crossed, and tripped the house circuit breaker.  I don't think he ever got that C128 fixed.
 
 
 

[kokapetl]

My soldering ability is good, but all I really own is a multimeter - no oscilloscope or the knowledge of how to use it to diagnose. Thanks for the reply, I'll try contacting Ray and will post results. Thanks again.

[jsixis]

I've seen cases where a deffective commie will blow-up a good power supply, but not the other way around!  Actually about a year ago somebody posted about how they tried wiring up a power supply to their C128, got the wires crossed, and tripped the house circuit breaker.  I don't think he ever got that C128 fixed.

 bad power supplies can definitely ruin a 128, if that 9volts AC hit 9.5vac chips will fry.

[kokapetl]

Any quick ways to test which one(s) fried?

[Hydrophilic]

If 9VAC went into 5V, then probably ALL of them are fried.  So buy another one... or listen to Ray... he routinely repairs them so he would know better than me.  All I know is general electronic circuit repair and the limits for the chips in the C128...  most of the chips have an absolute maximum voltage of +7V and a minimum of -0.2V.  But 9VAC has a peek positive voltage of +12V and a peek negative of -12V.  Way over the limit in both directions!

[kokapetl]

Thanks for the reply, I'll run a multi-meter check on the dodgy supply and work out exactly HOW bad it is.