Re: Apple II Minus Question

[mjmahon@aol.com (Michael J. Mahon)]

Vince Briel wrote:

>Inserting IC's into the sockets creates a friction that cleans and almost
>scrapes the contacts. It's the only way I know to clean sockets. You've
>replaced the RAM and 74xxx series IC's, so I'd try swapping out more, like
>the CPU, and anything else you can find. It might not be an IC but a
>component like a blown cap, or maybe even a bad solderpoint. Check over all
>solder spots with a magnifying glass. Look for cracks in the solder.

All good suggestions.

I once had a //e that failed in strange ways, and it turned out to
be a bypass capacitor near the 65C02.  One wire had become
fatigued (too many Zip Chip swaps ;-) and was broken right at
the board.

A ][+ (please, there is no such thing as a "minus"), once
stopped displaying color because the crystal went out of
spec.

Hairline PC trace cracks can also be an issue, depending on
the mechanical history of the board.

Swapping chips wholesale is generally not a good idea--"If it
ain't broke, don't fix it."

Rubywand's suggestion that diagnosis should proceed from
an observation of the symptom(s) is always good advice.

As you have observed, the Apple ][ does not have a hardware
reset (unless a Disk ][ controller is present), and must be
manually reset to get into the monitor.

Don't worry about DRAMs (dynamic, not static) coming up
in funny states--that's common.

-michael

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