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Re: Apple ][ original power supply restoration (Pt 2)...



    Phil,

    yes connect the resistor between the +5V and GND - try a 15 Ohm, a 10 
Ohm and a 5 Ohm (5-10Watts) and listen to PSU. If it continues to "chirp" 
check if the "chirp" frequency changes when changing the load which 
indicates that it does affect the feedback (if there's a "hard" short 
somewhere it usually won't change) so there could be a problem with the 
feedback circuit. Detailed schematics would be needed then to isolate and 
pinpoint the problem. I believe I don't have the schematics of the Apple II 
PSU so if you do feel free to send them to me so I can give you more 
detailed pointers on where to look.

    Luke

"Nama" <lord_philip@mac.com> ha scritto nel messaggio 
1143683948.904619.260570@i40g2000cwc.googlegroups.com">news:1143683948.904619.260570@i40g2000cwc.googlegroups.com...
> Thanks for the reply,
> I have not tried the resistor trick yet, but I did however plug the PSU
> into an old (dead) apple II+ motherboard that I have. The chirping
> continues unabated.
>
> Maybe I will try the resisitor test soon, however I suspect It won't
> make any difference.
>
> One quick question (as I'm a bit of a dumbo when it comes to
> electronics), do I put the resistor between +5V line and Ground line?
>
> Thanks again
>
> Phil
>