Re: My Apple ][+ is now very, very sad...

[John <john8520@gmail.com>]

That is interesting about those chips, I had always figured that after
10 years or so, all chips started to wear out a bit. Of course, the
one that is causing this problem (whichever one that may be) might of
had its lifetime shortened a bit by something like a card being
inserted while the system is on, or a temporary accidental short. Who
knows.

I myself did make a very silly mistake yesterday whilst swapping
around common 74LSxxx chips. I was removing a 74LS257, one that is
right under the powersupply connector, next to the first slot. Due to
its awkward location, my chip extractor grabbed the whole socket
instead of just the chip, and out it came. Not a huge problem, just a
minor setback requiring a trip to my local electronics store to get a
new 16pin socket as well as a bit of soldering time. Oh well, mistakes
are inevitable, but I am determined to get this thing running once
again!

John

PS- Tristan- I'll get that email to you as soon as I made a few
modifications to it.

On Jul 15, 6:05 am, Tristan Mumford <xtristan.xmumf...@xgmail.xcom>
wrote:
> Michael J. Mahon wrote:
> > John wrote:
> <snip>
> > Originally, it was thought that ICs would have a "bathtub shaped"
> > failure rate curve, but data indicates that the "end of life"
> > upswing isn't there--at least for values several times their
> > predicted lifetimes.
>
> So true. Especially when the ICs are powered by a nice reliable power supply
> free of spikes and other anomalies.
> Speaking of which I wonder how healthy the -5v rail is on the ailing II+
> power supply.
>
> Call me mad if you will, but does anyone else see the pattern of horizontal
> offsets and shades on the screen. I don't think enough is being read into
> that. I haven't studied the schematics too closely (even though I do need
> to, to resurrect an ailing II+ Clone). It could be anything from something
> obtuse like one of the MSB bits on a counter shorting to earth to a
> marginal supply being overloaded by too many active gates at one time.
>
> I know I'm not being too helpful, but a few more suggestions into the mix
> couldn't hurt.
>
> To the OP: If you happen to have the spreadsheet of components etc. still,
> could I please get a copy from you? My e-mail is
> xtristan_d0t_xmumford_at_xgmail_d0t_xcom with 'x's removed and punctuation
> substituted of course :)
>
> Tristan.
>
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