dlee@miro.Berkeley.EDU (David Lee) (12/16/86)
About two weeks ago I had an interesting experience with my Mac+. I turned it on and the screen was entirely black except for a pattern of white vertical blocky lines, no beep or nothing. The interesting part is that while staring at the screen for approximately 10 seconds thinking about what to do, the pattern of white vertical lines disappeared and the screen went "berzerk." The really interesting part came next, about 2 seconds after the screen went berzerk my Mac+ started to smoke! I was not imagining this, the distinct smell of burnt silicon was present. I finally turned my Mac+ off and the next day took it to the dealer to have it fixed (still under warranty). Well, when I got there, the dealer plugged in my Mac+ and it went on like nothing happened! So I took it home and have been using it ever since without any problems. Now, the thing I have been wondering about is what happened to my Mac+ when it smoked? I am afraid that one day when I am doing something really important my Mac+ is going to go berzerk again. Or maybe something more subtle is happening. I would be very interested if anybody else has had a similar experience or can tell me what condition my Mac+ is in.
ranger@ecsvax.UUCP (Rick N. Fincher) (12/16/86)
> my Mac+ when it smoked? I am afraid that one day when I am doing something > really important my Mac+ is going to go berzerk again. Or maybe something > more subtle is happening. I would be very interested if anybody else has had > a similar experience or can tell me what condition my Mac+ is in. By all means have your dealer open the Mac up and replace the analog board and power supply. Don't accept anything less than a complete replacement of those parts. Is your Mac+ an upgrade? Infoworld reported this week that some upgraded machines have been smoking and a few hav actually caught fire. All of the machines involved were 512K Macs upgraded to Mac+'s. Apple has said that the problem is that dealers are doing the upgrade improperly in some cases. If yours is a new Mac+, there may be a batch of defective power supplies. Many of the ones that have smoked have damaged the analog board, sometimes the heat has been bad enough to damage the main logic board and in a few rare cases, fire has destroyed the machine. If you bought a new Mac+ you may want to be sure that your dealer has not ripped you off by selling you a used 512K Mac upgraded to a plus because all of the problems have been with those Machines to date. Rick Fincher ranger@ecsvax
normt@ihlpa.UUCP (N. R Tiedemann) (12/17/86)
> About two weeks ago I had an interesting experience with my Mac+. I turned it > on and the screen was entirely black except for a pattern of white vertical > blocky lines, no beep or nothing. The interesting part is that while staring > ... > The really interesting part came next, about 2 seconds after the screen > went berzerk my Mac+ started to smoke! I was not imagining this, the distinct > I got there, the dealer plugged in my Mac+ and it went on like nothing > happened! So I took it home and have been using it ever since without any > my Mac+ when it smoked? I am afraid that one day when I am doing something > really important my Mac+ is going to go berzerk again. Or maybe something > more subtle is happening. I would be very interested if anybody else has had > a similar experience or can tell me what condition my Mac+ is in. I have had a similar experience with a VT100 terminal, most likely what happened is an overload resister burnt out. The video board has a few high power protection devices on it, and one of yours was bad. Well it took too much current and burnt itself out. Now everything works, because the only purpose of that device was for overload protection. In my case, I opened up the terminal, and from the brown marks I could tell which part was bad. Eventho it worked without the part I replaced it. I would recommend you taking it back to the dealer, telling him the story and have him check it out. The part should be easily found and replaced (and as long as it is under warranty). Norm Tiedemann AT&T Bell Labs ihnp4!ihlpa!normt
roy@phri.UUCP (Roy Smith) (12/17/86)
In <16644@ucbvax.BERKELEY.EDU> dlee@miro.Berkeley.EDU (David Lee) tells of
some problems he had with a Mac-plus. He turned it on, got strange video
for 10-15 seconds, then the machine started to smoke. When he brought it
in to be fixed, it worked fine, has has worked ever since.
One possibility is some sort of momentary short in the high-voltage
section. If you had some dust or something in the wrong place which
allowed the HV supply to arc, you might either produce enough EMI or drag
the power suply down enough to flake out the video. If the dust burned
away all by itself, that would account for the machine working fine later.
This is just conjecture, however.
Note that on high tension transmission lines, similar effects can
be seen. Most high-power circuit breakers are designed to automatically
reset themselves after a short time, in the expectation that whatever
caused the short (fallen branch, out-of-control automobile, small animal,
etc) has either burned up or fallen out of the way. A typical reclosing
program might include attempts after 1/15th (4 cycles), 1, and 15 seconds,
after which the breaker locks out, requiring manual intervention to reset.
--
Roy Smith, {allegra,cmcl2,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016
"you can't spell deoxyribonucleic without unix!"hogan@rosevax.UUCP (Andy Hogan) (12/18/86)
In article <16644@ucbvax.BERKELEY.EDU>, dlee@miro.Berkeley.EDU (David Lee) writes: > > About two weeks ago I had an interesting experience with my Mac+. ... > The really interesting part came next, about 2 seconds after the screen > went berzerk my Mac+ started to smoke! I was not imagining this, the distinct > smell of burnt silicon was present. I finally turned my Mac+ off and the next > day took it to the dealer to have it fixed (still under warranty). Well, when > I got there, the dealer plugged in my Mac+ and it went on like nothing > happened! So I took it home and have been using it ever since without any > problems. Now, the thing I have been wondering about is what happened to > my Mac+ when it smoked? All electronic components contain smoke. This is what actually makes them work. All that stuff they teach in schools about electrons, EMF, fields, holes, gates, etc. is just smokescreen. Its the smoke that does it. If components get too hot, some of the smoke (sometimes a lot of it) can be let out. This can happen from shorts, overvoltages, and just plain wear-n-tear. Once you let the smoke out, the component(s) don't work the same. They need to be replaced with new, smoke-filled components. (The non-hermeticity of all electronic component packages allows a very slow leakage of the smoke at all times, which is why all components, even the simple resistor, eventually fail.) All seriousness aside, if your dealer didn't even crack the case just because the Mac lit up like it was working, he/she did a really half-ass job. If you report smelling burning in any electronic gizmo, a competant repair person should open it, dismount any and all boards, and examine *both sides of* each one for crisped components OR board material. Under certain odd conditions I have seen components get hot enough to desolder themselves, or to blow holes in their DIPs. Yes, they might continue to work for a while, but you should insist (especially under warranty) on a thourough checkout. Take it back. If they don't believe you, take it somewhere else. Insist on a visual examination and a test with a heavy load on the power supply. Once it has been carefully examined and nothing appears to be burnt or crispy, you can conclude that you got lucky, and that not enough damage was done to cause a problem. In that case I would install a screen saver DA and run that sucker 24 hours a day, 7 days a week , except for powering up/down if your peripherals allow it, for the rest of the warranty period. This would be to push whatever component(s) did get hot to their limit, forcing any weakness to manifest itself. -- What's a noid? And why does everyone think I'm two of them? Andy Hogan Rosemount, Inc. Mpls MN