[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: wtb: original apple ][ broken as-is for parts



Liam Busey wrote:
Tristan Mumford wrote:

Liam Busey wrote:



-snip-


Entirely off the shelf? Good to know. I'm hopefully getting hold of a
rotten ][ I had in the next week or so. My initial intent was just to grab
it to take its mockingboard for my //e platinum. But then I started to
think I may fix it up a little and use it for a bbs or some kind of
esoteric online content.
And sorry, it is one thing I won't part with easily if you were wondering.


I'm not after you rotten ][. My moldy ][+ would get jealous. ;)

Well there are masked ROMs, a character generator, and a keyboard
encoder but those can all  be worked around.

The biggest issue with the II/ II+ is that for some reason Apple
decided to socket ever single chip on the motherboard (IIRC ~120
chips). While on the surface it may seem to be very convenient for
repairs, every one of those sockets is a weak or intermittent
connection waiting to happen. On a well kept machine this is no
problem. On a machine that's been sitting in someone's basement for 25
years, well .... AARRGHHHHH!!!!!! Tarnished chips and sockets are a
PITA!

Woz's motivation was exactly as you describe, to make it easy to
diagnose, repair, and experiment with the machine.  And avoiding
the reliability downside is why sockets have become reserved for
chips that are likely to be changed (like ROMs).

The good news is that sockets don't have to look good to be good.
The actual contact is made by less than 1% of the socket contact
area, and that is *exactly* the area that is scraped clean by
"scootching" each chip up about 1/16" and then reseating it.

It's an unusual (and well-worn) socket that can't make good
contact with a chip pin after reseating.

-michael

NadaNet networking for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."