The General Approach to Computing - A Ramble
lists at databasics.us
Thu Apr 23 15:04:08 CDT 2009
Subject was:Re: AppleColor RGB Monitor (IIGS) help?
Tony Duell writes:
The most basic test is to remembner that a transistor has 2 diode
junctions, one between base and emitter, the other between base and
collector (no, you _can't_ make a transistor from 2 diodes!). So you
can test each of those junctions as a diode using either an analogue
ohmmeter, or more likely these days the diode-test range of a DMM.
Well, thanks, Tony. This is the first time I was confident I had
exactly the right info to help another list member diagnose a problem in
a couple of months, and you go and spoil it. Sheesh! (Just kidding...
mostly.) Complicated questions on specific equipment from companies
whose equipment I have not used makes trying to help out on this list
significantly more difficult.
FWIW, I almost always learn something from your posts, except in those
instances where your post confirms what I already knew, and gets there
before I even read the question. You're quite an excellent resource for
the list, and I heartily approve of your approach, in terms of being
able to fix one's own equipment. That USED to be a necessary part of
Back in the day of my IMSAI 8080 and CP/M 1.3, I was approached by a
friend (since I had a computer, and they were magic) to keep a mailing
list, with extra information, for a 500+ member newsletter. The
director would keep track of changes, and come over to my place to make
the changes on the list, and run the program I wrote to print the labels.
One month, the director came over and caught me by surprise, it not yet
being the very last day possible to print the labels. I invited him in,
and expressed my willingness to get started. He began to laugh. I
asked him why. He said "Don't you know what you just said? I asked if
you were ready to add some names, and make some changes to subscription
dates, and you replied 'Fine, I'll go get my soldering iron.' "
That's not as odd as it sounds, and, no, it wasn't a hard-wired
program. My IMSAI had 15 boards of 4K each of 2102 memory, and
replacing chips was about an hourly task. Heck, I even wrote my CONST
(console status routine for CP/M) such that if there was no character
ready, it would test one memory location before returning. Made
interesting patterns on the LEDs.) Computer clubs were places people
went to get soldering tips as much as discuss programming, despite
having Gordon Eubanks (Symantec, Basic-E, CBasic) as a member, and
frequent appearances by Gary Kildall (author of CP/M) in the club, the
software discussions were always for AFTER people had their machines
Sorry for the digression. The point being that it used to be MANDATORY
to be able to fix one's own computer, lest one become dependent upon the
pity of others to get anything done. I find that approach still useful
to some extent, and I've always been able to fix my own machines at
least as well as the (generally) trained-chimp-level techs at local
fix-it shops. That many orders of magnitude of complexity have come and
gone since the IMSAI days are good, in terms of what one's money will
buy today, but bad in that one is much less likely to be able to fix
one's own equipment to component level. It's not as satisfying to say
"Hmmm. You need a new video card" as to hold up the offending
transistor and cackle. Or is that just me?
I guess, to sum up this ramble, Thanks, Tony! I enjoy reading your
posts, and appreciate your mind-set on the issues.
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