granteri@pnet51.cts.com (Grant Erickson) (04/14/89)
For the past 6 months, my Mac 512KE has had a severe screen jitter/flicjer problem. It has been upgraded using a MacSnap 524S board, giving it one megabyte. There are two bright lines, about 1/8 inch thick, at 1/5 of the screen down, and 1/5 up the screen. These lines bounce in that constrained area, but never go into the middle 3/5 of the screen. I took the Mac in 3 times to the dealer, and they could not find a single thing wrong with. So much for $90 in opening the Mac 3 times :-) As of 3 weeks ago, it also started to make a high pitched noise every now and again also, not eminating from the speaker however. I am very puzzled on this one. And the lines are hard on the eyes 8-(. If you have any helpful information, please leave me E-Mail, and don't post replies through the net, as I may not get them. Thank you. .________________________________________________________________________________. | UUCP: {amdahl!bungia, uuner!rosevax, chinet, killer}!orbit!pnet51!granteri | | ARPA: crash!orbit!pnet51!granteri@nosc.mil | | INET: granteri@pnet51.cts.com | !_______________________________________________________________________________!
dswt@stl.stc.co.uk (Stewart Tansley) (04/18/89)
In article <941@orbit.UUCP> granteri@pnet51.cts.com (Grant Erickson) writes: >For the past 6 months, my Mac 512KE has had a severe screen jitter/flicker >problem. It has been upgraded using a MacSnap 524S board, giving it one >megabyte. There are two bright lines, about 1/8 inch thick, at 1/5 of the >screen down, and 1/5 up the screen. These lines bounce in that constrained >area, but never go into the middle 3/5 of the screen. I took the Mac in 3 I have had a similar symptom on my Mac+, also occuring over the past 6 months or so. Being surprised to see such a similar description, I thought I'd make a posting rather than mail Grant. (I'm also not confident of being able to mail him from here, either.) I too have seen these flickering bright lines, although I haven't had the whistle -- yet! :-) I have also had a shimering effect elsewhere on the screen. From my b+w TV meddling, years ago, I recall the line- scanning circuit (of the VDU - analogue stuff) would be the likely culprit, with some sort of component degradation being the cause. When I get a moment, I'll have a peek inside the case (its out of warranty!). You have to know what you're doing though... Up till now, my solution has been to give a gentle 'thwack' to the top of the Mac case, and the problem goes away for a while! (cf. old TV sets!) Disclaimer: 'thwack' at your own risk! =========================================================================== Stewart Tansley STC Technology Ltd +44 279 29531 ext 2763 London Rd, Harlow, UK dswt@stl.stc.co.uk CM17 9NA (JANET) dswt@uk.co.stc.stl (UUCP) ...uunet!mcvax!ukc!stl!dswt =========================================================================== =========================================================================== Stewart Tansley STC Technology Ltd +44 279 29531 ext 2763 London Rd, Harlow, UK dswt@stl.stc.co.uk CM17 9NA (JANET) dswt@uk.co.stc.stl (UUCP) ...uunet!mcvax!ukc!stl!dswt ===========================================================================
js9b+@andrew.cmu.edu (Jon C. Slenk) (04/21/89)
Sometimes monitor problems are associated with the power supply unit. Sincerely, Jon Slenk / js9b.