terence@cory.Berkeley.EDU (Terence Chang) (05/29/89)
Almost a year ago I had my Mac+'s motherboard replaced -- the y told me the CPU, RAM, and everything else was just fine. But my Mac has never been the same. Yesterday and today, I got the sad Mac error code 0300FF (a RAM test failure) which was no surprise, because the usual pattern of diagonal stripes that follows a cold start was glitched. Badly. Columns of extra pixels in the middle of the screen and columns of missing pixels on the right side. I waited for the Mac power supply warm up. No effect. Thumping the sides of the Mac didn't change things -- same ugly patterns followed by the sad Mac. Then I put the Mac on its side and spanked its bottom. And voila! Up and running without a single misplaced pixel. First there was the cold start and the warm start, and now the Han Solo start. Does anybody know what's really wrong with my Mac? Terence ----- "People who get nostalgic | Terence Chang: about childhood were | e-mail: !ucbvax!cory!terence obviously never children." | terence@cory.berkeley.edu "Calvin and Hobbes" | or an acceptable facsimile thereof
jcocon%hazel.cs.clemson.edu@hubcap.clemson.edu (James C O'Connor III, 2846) (05/30/89)
From article <14233@pasteur.Berkeley.EDU>, by terence@cory.Berkeley.EDU (Terence Chang): > > Almost a year ago I had my Mac+'s motherboard replaced -- > the y told me the CPU, RAM, and everything else was just fine. But [problems with booting] I had similar problems once. The Mac has a paper/tin foil rf shield on the bottom of the mother board. Somehow it was shorting out a few pins. I know it is coated with non-conductive paper on the mother board side, but replacing it stopped my Mac from being very sad. I'd tried everything else short of replacing the motherboard, and this did the trick. (Besides, it only costs a few bucks). Jim
terence@cory.Berkeley.EDU (Terence Chang) (05/30/89)
In article <5637@hubcap.clemson.edu> jcocon%hazel.cs.clemson.edu@hubcap.clemson.edu writes: >I had similar problems once. The Mac has a paper/tin foil rf shield on the >bottom of the mother board. Somehow it was shorting out a few pins. > . . . Four people mailed me already (less than 10 hours after posting, wow thanks) mostly suggesting that the SIMMs might need cleaning or reseating. But I think I do have a short -- if I place my ear against the case, I can hear a faint nonperiodic tick-tick-tick coming from the motherboard (this is with the hard drive powered down of course) which sounds likes a spark gap. I tried to explain this to the Mac repair tech, but he insisted that it was the *speaker* that was making the sounds -- it's ticking for at least two years now. Argh. I'll inspect the motherboard as soon as I buy those wonderful gidgets you need to open the case :( . Terence ----- "People who get nostalgic | Terence Chang: about childhood were | e-mail: !ucbvax!cory!terence obviously never children." | terence@cory.berkeley.edu "Calvin and Hobbes" | or an acceptable facsimile thereof
thecloud@dhw68k.cts.com (Ken McLeod) (05/30/89)
In article <14233@pasteur.Berkeley.EDU> terence@cory.Berkeley.EDU (Terence Chang) writes: >Mac error code 0300FF (a RAM test failure) which was no surprise, >because the usual pattern of diagonal stripes that follows a cold >start was glitched. Badly. Columns of extra pixels in the middle >of the screen and columns of missing pixels on the right side. > > Then I put the Mac on its side and spanked its bottom. And >voila! Up and running without a single misplaced pixel. First >there was the cold start and the warm start, and now the Han Solo >start. Does anybody know what's really wrong with my Mac? Yes. One (or more) SIMMs aren't making good contact. Open up the Mac and reseat the SIMMs; they've probably just worked loose. -- ========== ....... ============================================= Ken McLeod :. .: UUCP: ...{spsd,zardoz,felix}!dhw68k!thecloud ========== :::.. ..::: INTERNET: thecloud@dhw68k.cts.com //// =============================================
hgw@julia.math.ucla.edu (Harold Wong) (05/31/89)
In article <14233@pasteur.Berkeley.EDU> terence@cory.Berkeley.EDU (Terence Chang) writes: > >Mac error code 0300FF (a RAM test failure) which was no surprise, >because the usual pattern of diagonal stripes that follows a cold >start was glitched. Badly. Columns of extra pixels in the middle >of the screen and columns of missing pixels on the right side. > stuff deleted > > Then I put the Mac on its side and spanked its bottom. And >voila! Up and running without a single misplaced pixel. First >there was the cold start and the warm start, and now the Han Solo >start. Does anybody know what's really wrong with my Mac? > Easy, I had a semi/simular situation. I has just upgraded the memory in my SE and it turned out that the SIMM boards were a little too thick. When I stuffed the memory into the SIMM Sockets, I broke two of the pins and the Mac started up with memory error and the missing stripes. I would guess some of the pins on your SIMM socket lost connection with the SIMM and when you hit it, made contact. This is a warning to all Mac users. If you are upgrading Mac memory, watch out for SIMM boards which are too thick. If it takes effort to stuff them in, then it's too thick. Serious damage can result on your mother board. Also watch out for SIMM boards which are too thin. If they slosh around after you install them, they are too thin (also, you will not be able to start up the Mac), you might have the same problem as terence did. ------------------------------------------------------------------------------- Harold Wong (213) 825-9040 UCLA-Mathnet; 3915F MSA; 405 Hilgard Ave.; Los Angeles, CA 90024-1555 ARPA: hgw@math.ucla.edu BITNET: hgw%math.ucla.edu@INTERBIT