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Re: Hints/feedback on disk reading failure on Apple IIe



IceMan wrote:
  Warren,

    thanks for the tip, infact that's just what i was looking for.
Additionally, I found some IIgs memory expansion cards - do you happen to
know if the dram chips on these cards are the same 64kbit type as used on
the IIe? If so, as I won a bid I will be getting some (mixed card, with
superserial and disk controller) so I was wondering if I could use the
chips.

No, the IIgs (and most other) memory expansion boards use 256K DRAMs.

There are plenty of 64K DRAMs floating around though, so you shouldn't
have much trouble locating a couple.

    BTW here are a couple of pics I made of my IIe and board:

http://www.applefritter.com/image/uid/13452

    Yes I am handy with a soldering iron:) I can manage to unsolder smd
components and ICs (I have developed my own technique) without the need of a
heat gun and without "frying" them. Well, I have a good soldering iron
(Weller), but the hand does the real work!

Congratulations--most people who do this rarely make a mess of it.  ;-)

Too much heat for too long is the biggest problem, causing delamination
of the traces from the board and occasionally heat death of a chip.

You and Warren should both be aware that sockets, while handy when a
chip *does* fail, are a much bigger source of problems than the chips
themselves.  This is why *only* components that have a high probability
of replacement are usually socketed (like EPROMs).

It is also why most "dead" Apple II's are fixed by "scootching" the
chips up and down in their (poorly contacting) sockets.

Be thankful for every soldered-in chip--it is much less likely to
fail due to actual chip failure than due to socket/lead contact
failure.

As to the convenience of socketed chips saving dead boards from
being junked, I'm sure that the vast majority of junked Apple II's
were perfectly functional, but perceived as obsolete.  Of the
remaining few percent, most "dead" Apple II's would have been
junked whether socketed or not, since only a tiny fraction of
owners have any clue about chip-level diagnosis and replacement.

Of the remaining tiny fraction of a small fraction, some of those
who do not solder were perhaps discouraged by the lack of sockets,
but many more simply considered that $5-$10 for a new board (or
computer) was less trouble than doing the diagnosis and repair.

It is quite easy to junk something that would take an hour or
two to fix when a full replacement is so easily done.

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

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

    Thanks for any info.

    Best regards,

                Luke

"Warren Ernst" <wernst@gmail.com> wrote in message
1133461430.846456.197250@g49g2000cwa.googlegroups.com">news:1133461430.846456.197250@g49g2000cwa.googlegroups.com...

Congratulations!

Amazingly, you and I are almost in the same boat. I've dug out, cleaned
up, and turned on my beloved //e this week, and the last time it was
booted was 1994. Fortunately, I have a spare //e saved from a dumpster
earlier this year for spare parts, some of which I've had to use.

In a past life, I worked at Beagle Bros, where I have seen more than my
fair share of //e's, and I am always amazed how, in my experience,
about half of the "first generation" //e motherboards I've worked on
have every chip socketed, and about half have most of their smaller
chips soldered on. I'm very lucky that my main //e has all-socketed
chips, and have wondered how many boards were junked just because
someone couldn't replace a failing chip on a socket-less board.

At any rate, I'm glad to see you're handy with a soldering iron.

Extended 80-column cards are going for just a few dollars on ebay these
days, so getting a replacement shouldn't be too tough. If you go this
route, be sure NOT to get a standard "80-column card," for it lacks the
extra 64k you'll probably want.

Or if you want to go nuts, look for a RamWorks-style memory card, which
will get you 80 columns, and memory to 512k and beyond.

Take care,
Warr