chavez@ucbvax.BERKELEY.EDU (Thomas M. Chavez) (04/29/86)
Just today my Mac screen started waving back and forth, sort of rippling from top to bottom. I don't think that I am over heating because I have my new Fanny Mac keeping the temperature down, and the line voltage is right at 120V. Has anyone else seen this problem? Is my analog board going to blow? Should I buy Apple Care before it does? (How much is an analog board?) Any help is much appreciated... Tom ucbvax!chavez
gjb@unirot.UUCP (Greg Brail) (05/01/86)
In article <13507@ucbvax.BERKELEY.EDU> chavez@ucbvax.BERKELEY.EDU (Thomas M. Chavez) writes: >Just today my Mac screen started waving back and forth, sort of rippling from >top to bottom.... >Has anyone else seen this problem? I've never seen the problem on the Mac, but it seems to happen on Apple IIc's with the little Apple monitors. Each row of pixels sort of does a 'wave' left and then back to the right, one after the other. I'm not sure about overheating, but I know the problem is solved temporarily by jiggling the monitor cable at the jack. In other words, the monitor connection on your Mac may be loose. Good luck. -Greg -- Greg Brail (Greg @ The Soup Kitchen) UUCP : ..{ihnp4,seismo,harvard,ut-sally,allegra}!caip!unirot!gjb ARPA : unirot!gjb@caip.rutgers.edu USNAIL : Don't bother.
hal@ecsvax.UUCP (Hal Hunnicutt) (05/02/86)
> Just today my Mac screen started waving back and forth, sort of rippling from > top to bottom. I don't think that I am over heating because I have my new > Fanny Mac keeping the temperature down, and the line voltage is right at 120V. > Has anyone else seen this problem? Is my analog board going to blow? Should > I buy Apple Care before it does? (How much is an analog board?) > [] Some time ago, after blowing 3 power supplies (ouch!), I decided to cool the sucker off. I took an ordinary desk fan and set it on top of the mac blowing down on the power supply vents. Rather crude, I would admit but it made the screen do a wild belly dance exactly as you describe. I suspect its an RF interference, because the waving would decrease the farther I moved the fan away from the mac. My eventual solution, by the way, was not to wait for a commercial fan and pay ~130 bucks for it. I went down to the local Radio Shack and bought one of their little 4" general purpose fans. It's a near perfect fit between the back of the disk drive and the mac frame. A velcro patch on the bottom and a little styrofoam wedged on either side provide more than adequate security. All I had to do was connect one wire to the ground on the frame and the other to the power switch and presto! An internal fan with instant power-on -- for $15! It's a little on the loud side, but it's nothing I couldn't get used to for the price (not to mention $100 a power supply). Besides that sucker is cranking out about 32 cubic feet per minute (twice as much as System Saver Mac), so you cna rest assured that it never gets the least bit warm. I've done two such installations and it takes about 10 minutes. Hal Hunnicutt hal@ecsvax.UUCP > Any help is much appreciated... > > Tom > ucbvax!chavez -- "And a now my friend, the first a rule, of Italian driving: What'sa behind you, is a not important." -Franco
phil@portal.UUcp (Phil Sih) (05/05/86)
In article <557@unirot.UUCP>, gjb@unirot.UUCP (Greg Brail) writes: > In article <13507@ucbvax.BERKELEY.EDU> chavez@ucbvax.BERKELEY.EDU (Thomas M. Chavez) writes: > >Just today my Mac screen started waving back and forth, sort of rippling from > >top to bottom.... > >Has anyone else seen this problem? > > I've never seen the problem on the Mac, but it seems to happen on > Apple IIc's with the little Apple monitors. Each row of pixels sort > solved temporarily by jiggling the monitor cable at the jack. In > other words, the monitor connection on your Mac may be loose. Good > luck. > I used to work in an office with about 50 or so Macs and two of them had this same problem and finally died of power supply failure, one with quite a bit of smoke. I have another two friends who have had theirs fail in a similar way, again the problem was with the power supply. A friend of mine who used to work at Apple indicated this symptom usually is an indicator of impending powersupply failure. I would be careful. One of my friends said it took months to get his machine repaired after the unit blew. - Phil { sun | hoptoad | atari } !portal!phil
wmartin@ut-ngp.UUCP (Wiley Sanders) (05/06/86)
In article <13507@ucbvax.BERKELEY.EDU> chavez@ucbvax.BERKELEY.EDU (Thomas M. Chavez) writes: >Just today my Mac screen started waving back and forth, sort of rippling from >top to bottom. I don't think that I am over heating because I have my new >Fanny Mac keeping the temperature down, and the line voltage is right at 120V. >Has anyone else seen this problem? Is my analog board going to blow? Should >I buy Apple Care before it does? (How much is an analog board?) > If the "rippling" is a quick, jerky, kind of thing, yes, you are sooner or later going to need a new analog board. I bought a 128K Mac soon after they came out. About a year ago, my video display began to spazz out, especially during the first 15 min after warmup. Eventually it would stabilize. Then, about two months ago, the problem began to get worse and worse, quickly. One day I turned the Mac on and there was nothing but a bright vertical line on the screen, so I got the analog board replaced. I heard a rumor there were a lot of these problems with the first Macs. My new board has a much brighter dis- play; I used to keep the brightness control pretty much full up, I keep it at about 75% now. The moral: Live with the problem as log as you can, but eventually you'll need a new analog board. -w
chavez@ucbvax.BERKELEY.EDU (Thomas M. Chavez) (05/13/86)
In article <13507@ucbvax.BERKELEY.EDU> you write: >Just today my Mac screen started waving back and forth, sort of rippling from >top to bottom. I don't think that I am over heating because I have my new >Fanny Mac keeping the temperature down, and the line voltage is right at 120V. >Has anyone else seen this problem? Is my analog board going to blow? Should >I buy Apple Care before it does? (How much is an analog board?) > >Any help is much appreciated... > >Tom >ucbvax!chavez Here is a reply that I got: Tom; A few key words in your article tip me off to the probable cause. (forgive if this is way late I'm behind with net.micro.mac). The first tip is NEW <insert your fan name here>. The second is JUST TODAY. This leads me to believe that the wavy lines came with your fanny mac. Actually its not just the fanny macs fault although now I know I wont buy one. They should have taken care of this problem. Those wavey lines are most likely caused from the magnetic fields generated by the fanny mac fan. I installed (hacked) a muffin fan into mine and it does the same thing. Some fans are worse and some are better. Just try taking the fan off, presto waves go away. Move it around the tube, have some fun. For ~95.00 I would have expected them to work around this some how with shielding or different fans (like those that come with the monster mac, I dont think they cause waving.) If it is really bad and anoying I would get my money back and go for one of those internal "flapper" types that everyone is talking about, although they are hard to get. Hope it helps dave schuh ----------------------- Well, I took my FannyMac off and the problem disappeared! And when I put the fan back in proximity to the mac, the waving reappeared. Such a simple solution. Now, should I get rid of the fan and have a smooth screen or keep it and watch the waves... Thanks for all the replies... Hope this helps someone. Tom Chavez ucbvax!chavez
jer@peora.UUCP (J. Eric Roskos) (05/16/86)
> My new board has a much brighter display; I used to keep the brightness > control pretty much full up, I keep it at about 75% now. There's a control on the analog board (as is the case on the video boards for most terminals and also most TV sets) that controls the maximum brightness available from the user-accessible brightness control. In most video boards (thus probably in the Macintosh too) it is actually just another potentiometer in series with the brightness control (usually there's another fixed resistor in series too, just in case you turn both to their minimum-resistance position). In some TV service manuals I've seen, you set the internal control to give a particular voltage level when the external control is set at maximum brightness, so it's probably best not to haphazardly change it. Regarding the power supply, though... for about 6 months I've been periodically asking in here "what part fails"... well, mine finally failed, and I found out: when it started giving the "jerking" display described in the above posting, I showed it to one of our hardware maintenance people next door, who said "oh, that means the insulation's breaking down in the flyback transformer, usually, although also sometimes the magnets on the yoke may be coming loose". He said I could get a new flyback transformer from one of the local electronics parts places, but finally I took it in and got the board swapped, just to be safe. I notice that the new board has a different flyback transformer, and also it seems to be farther away from some of the nearby components, so maybe it was arcing to an adjacent component in the early boards... or maybe it was just a defective lot of transformers. Incidentally, I notice in my new power supply board that three of the heat sinks have stubs of wires from rectifiers on them, where apparently they took the rectifier + heat sink out, cut off the rectifier, and reused the heat sink on a TO-220 transistor instead (so they didn't have to reuse the hole where the rectifier lead was soldered). This makes me think those rectifiers must also fail frequently, which in turn makes me think it really *does* get too hot in there... -- E. Roskos
hsgj@batcomputer.TN.CORNELL.EDU (Dan Green) (05/19/86)
In article <2177@peora.UUCP> jer@peora.UUCP (J. Eric Roskos) writes: >[...] > >Incidentally, I notice in my new power supply board that three of the >heat sinks have stubs of wires from rectifiers on them, where apparently >they took the rectifier + heat sink out, cut off the rectifier, and >reused the heat sink on a TO-220 transistor instead (so they didn't have >to reuse the hole where the rectifier lead was soldered). This makes >me think those rectifiers must also fail frequently, which in turn makes >me think it really *does* get too hot in there... >-- >E. Roskos At the terminal center where I work there are 40 macintoshes (512K) which are on continuously 20 hours a day, seven days a week (ie they are always in use...). At least once a day, one of the macs will mysteriously crash because, in my humble opinion, it is overheating. The vents on the top get very warm. If a user puts a book or papers over the top vents the probability of a crash goes up by about 90% :-(. Occasionally I use PC's, and while I am not fond of the fan noise, I am at least reassured that the thing won't crash due to overheating. Of course, I must admit that the PC's are usually empty while the Macs are usually in use... -- Dan Green BITNET: hsgj@cornella ARPA: hsgj@vax2.ccs.cornell.edu ~~~~~~~~~ UUCP: {decvax,ihnp4,allegra}!cornell!batcomputer!hsgj
cjn@calmasd.UUCP (05/20/86)
The Mac Plus does use a different flyback than the old 512s.