Re: Vulcan IIgs Power Supply Repair

[Michael Black <et472@ncf.ca>]

On Sat, 7 Jul 2012, Polymorph wrote:

> Hi all,
>
> I recently acquired a Vulcan IIgs which was originally working. However, 
> shortly after getting it, the fan died. I replaced the fan with a spare one I 
> had lying around, but after I had fitted the new fan, the power supply 
> stopped working. It repeatedly turns on and off really quickly. I believe 
> this is normal behaviour if no load is detected, but I have tried it with or 
> without plugging it into the IIgs' motherboard socket and it behaves the same 
> way. The motherboard power light flashes on and off repeatedly. This sounds 
> very reminiscent of a problem Antoine had mentioned with his //e in 2009 
> (https://groups.google.com/d/topic/comp.sys.apple2/Hc95ZUUC8gI/discussion) - 
> which funnily enough I commented that I hadn't seen that behaviour before!. I 
> should also mention I have since removed the fan in question - not that I 
> think it should cause any problems (it is rated similarly to the original), 
> but I've been wrong before.
>
> I replaced the 2 large 150uF 250V capacitors thinking it to be the likely 
> failure point, but it hasn't made any difference. I have done this before in 
> other power supplies and have had good results. This time it appears to be 
> something else...
I wouldn't think those would be the problem.