Re: IIgs won't start up -- ZipGS dead?

["Michael J. Mahon" <mjmahon@aol.com>]

Mitchell Spector wrote:
> Day 2, a little more testing...
>
>     The only way I can get the yellow LED (cache activity) to light
> up is by pressing on the oscillator. Even then it often just flickers
> on for a second, but I can see the action of_pressing_ on the
> oscillator socket causes the LED to blink on and off...obviously
> there's a loose connection here.
>
>     Further proof, if I firmly press down and continuously keep my
> finger squeezing the oscillator it stays lit up and even lights back
> on after doing a Control-Reset on the keyboard. I still cannot get
> the IIgs to show *any* signs of life--black screen and no sound.
> You would think holding down the oscillator would get it to boot
> up, unless maybe more than one of the 4 pins have a break, or
> now the 40-pin CPU socket is hosed from all the resocketing
> I tried last night.
>
>     Is it normal for the yellow cache LED to not light up on power
> up, or touching the socket/oscillator to make it intermittently turn
> on and off? I'm 99% the answer is "no" but I don't have another
> ZipGS in front of me to compare with.
>
>     What are the chances resoldering the oscillator socket will
> fix this? Is there a possibility something else is damaged based
> on the symptoms I've described?

It sounds like the oscillator socket is not making reliable
contact with the oscillator pins.  This is not unusual, since
some oscillators have sturdier pins that can spread the
spring contacts of the socket.

Unfortunately, the best remedy is to replace the oscillator
socket with a new, high-quality socket.

Practice your soldering skills before attempting this,
because the fine copper traces on the board are easy
to "lift" in the desoldering part of the process.

It sounds like there is another problem too, but first
things first.

-michael