Re: IIGS - Clock/PRAM chip

["Polymorph" <polymorph69@hotmail.com>]

David Wilson wrote:
> On Feb 16, 1:40 pm, "Polymorph" <polymorp...@hotmail.com> wrote:
> > I have verified that voltage is being applied, but if someone could
> > provide more details on the clock chip, it might shed some light on
> > where the problem lies. Does anyone have details on what each pin of
> > the IIgs clock chips is for or where this info can be found?
>
> Apple IIgs Hardware Reference (2nd edition) available from Syndicomm
> has ROM0/1 and ROM3 IIgs motherboard schematics. The pinout of the
> clock chip is:
>
> 1 1SEC (probably 1Hz squarewave output)
> 2 XIN
> 3 XOUT
> 4 GND
> 5 EN*
> 6 DATA
> 7 CLK
> 8 VCC
>
> EN*, DATA, CLK and 1SEC go to the VGC (DATA and 1SEC have 4.7k pullup
> resistors).
> XIN and XOUT are the 32768Hz crystal pins.

Thanks David. That info might help me diagnose what the problem is. As
Michael said above, its probably more likely to be some problem with
the power getting to the chip rather than the chip itself, but you
never know. In my case it would be something between the power supply
and the clock chip - maybe a dodgy filter capacitor or something?

cheers,
-p