B5U@PSUVMB.BITNET (10/21/86)
My roommate, an Apple // owner since 1980 (first a //+, now a //e) and I were
talking about the IIGS when he commented that the power pack on the GS was the
same as in his //e, and the same as in the //+. He also commented that he did
not need a surge protector on his //e (as I have one on my Mac +) because of
how well his power pack was built. He also maintains that above a surge of
approx. 150 volts, the Mac power source would go boom, where his would take it.
Also, that his computer would take no damage, where the Mac might.
The only experience that we have is when a friend of ours had his Mac smoke
at one of CMU's dorms, after a faulty line carried 220 volts to the computer,
taking out all electrical devices. After a check, the only damage to the Mac
was burned insulation on the incoming power line.
Finally, he maintains that the power pack in the // series is SMALLER by
components, as if you had to box it, the pack would end up bigger from the Mac.
Well, can any of the gurus of the hardware world (HELP APPLE CORP.) answer/
refute my roommate (a senior EE that I have always felt knew what he was doing)
?????????
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George A. Brownfield
Aerospace Engineering '87
The Pennsylvania State University
Bitnet: GAB @PSUECL
UUCP: {akgua,allegra,cbosgd,ihnp4}!psuvax1!psuvmb.bitnet!b5u
"We don't get laid much, but we're building the future"
-Engineering majors, according to Robin Williams
=========================================================================wtm@neoucom.UUCP (Bill Mayhew) (10/24/86)
The last time I looked, I was Baron over about 14 apple ][ and //e computers. No GS yet. I have had a lot of trouble with the power packs in the ][ and // versions. We have pretty good power here; it stays right about 119.5 volts with just a little rf hash from various devices around the building. We get occasional transients from things like air conditioner motors, but those are rarely greater than +/- 10 volts riding on the regular a.c. We use The apple computers for lab. data acquisition. I have several that are used for long term monitoring of eeg signals from rats. On these computers, the power packs usually konk out after about 3-4 months of continuously on operation. The failure mode is quirky. What happens is that once the power packs are shut off and cool down, they do not want to turn on again. When turned on again, the Apple will sit there inert for about 10 minutes, and then suddenly the power pack will wake up and turn on. Some times the computer will crash a couple of times in the first few minutes as the power pack "flickers". I think if you peek in the back room of your friendly neighborhood Apple dealer, you are likely to see a pretty high stack of gold and / or silver dead Astec power supplies! Note that we haven't been over-taxing our Apples. Generally they have a Moutain A/D-D/A, 16K card, and disk drive(s). The drives are used only infrequently as the data comes in. I've done post mortems on a couple of the fried-out supplies. Generally, I'd say that trying to repair one that has failed as above isn't worth your time, as multiple components degrade with age. The high-voltage energy storage capacitors get leaky, the switching transistor degrades, and in one case the RF transformer shorted out. Lately, I've started using third party power packs. If memory serves me right, the one from Jameco is pretty good. It also has vent holes to allow air to circulate inside the power pack to keep the temperature down, which should improve the life of the capacitors. Be ware of the cheap replacements: you get what you pay for! As far as using surge protectors goes, it's probably not necessary with the Apple ][ and // (and presumably the GS) uless you've got a really serious power problem. If your power is really that bad, you'll have to get a really good power conditioner to clean it up! We don't have any McIntoshes here so I can't comment directly. There is no reason to believe that the Mac power unit is a vastly different technology from the ][. The Mac is likely to be more reliable as air can more easily circulate through the supply! Component count rarely says very much about the reliability of a power supply; the quality of the design engineering matters more. Given the per-part reliability is equivalent, something with more parts is more likely to fail in a statisitical sense; this ignores the overall sensibility of design, though. One last word about surge protectors. Most of the cheap ones I've seen don't really protect your computer. You'd be better off unplugging your computer when it is not in use, and buying a couple of boxes of diskettes instead. Bill Bill Mayhew Division of Basic Medical Sciences Northeastern Ohio Universities' College of Medicine Rootstown, OH 44272 USA phone: 216-325-2511 (wtm@neoucom.UUCP or ...!cbatt!neoucom!wtm , etc.)