paulc@hpsad.HP.COM (Paul Christensen X3073) (03/20/91)
Anyone out there having video problems with the A300? I have noticed that when I first fire up my A3000, the screen jitters for a few mins, then seems to stabilize after a while... Ever seen this? Anyone have ideas pointing to a possible cause? Or fix? Thanks, Paulc
vfg2@phx.mcd.mot.com (03/26/91)
In article <12870002@hpsad.HP.COM> paulc@hpsad.HP.COM (Paul Christensen X3073) writes: >Anyone out there having video problems with the A3000? >I have noticed that when I first fire up my A3000, the screen jitters >for a few mins, then seems to stabilize after a while... Ever seen this? I take it you're not talking about the well-documented 1950 screen jitter problem, where the whole screen bounces up and down in unison at random. My 3000's video looks wavy at powerup, i.e. some lines are bent horizontally. Is this what you mean? If I cycle the power, it does not recur. It only happens when the 3000 is cold. It goes away within 30 seconds for me. Believe me, I'm keeping an eye on this! If it gets any worse, into the shop she goes! Yours is the first post I've seen that sounds like someone might have the same trouble I have, but I've only been an Amigoid :) for 3 months... --------------------------------------------------------------------------- Dan Quella, vfg2@phx.mcd.mot.com Somehow, someday, we need Just One Victory, and we're on our way ____________________________________________________________ - Rundgren ___
hood@cbmvax.commodore.com (Scott Hood) (03/27/91)
In article <14760@mcdphx.phx.mcd.mot.com> vfg2@phx.mcd.mot.com writes: >In article <12870002@hpsad.HP.COM> paulc@hpsad.HP.COM >(Paul Christensen X3073) writes: > >>Anyone out there having video problems with the A3000? > >>I have noticed that when I first fire up my A3000, the screen jitters >>for a few mins, then seems to stabilize after a while... Ever seen this? > >I take it you're not talking about the well-documented 1950 screen jitter >problem, where the whole screen bounces up and down in unison at random. > >My 3000's video looks wavy at powerup, i.e. some lines are bent horizontally. >Is this what you mean? If I cycle the power, it does not recur. It only >happens when the 3000 is cold. > >It goes away within 30 seconds for me. Believe me, I'm keeping an eye >on this! If it gets any worse, into the shop she goes! > >Yours is the first post I've seen that sounds like someone might have >the same trouble I have, but I've only been an Amigoid :) for 3 months... > >--------------------------------------------------------------------------- > Dan Quella, vfg2@phx.mcd.mot.com > Somehow, someday, we need Just One Victory, and we're on our way >____________________________________________________________ - Rundgren ___ Make sure that you first try the fine-tuning adjustment for the A3000's display enhancer as per the user's manual. Sometimes if the fine-tuning is just on the edge of correct operation, you can experience a jittery display (horizontal only). Regards, Scott Hood -- -- Scott Hood, Hardware Design Engineer (A3000 Crew), Commodore-Amiga, Inc. {uunet|pyramid|rutgers}!cbmvax!hood hood@cbmvax.cbm.commodore.com "The views expressed here are not necessarily those of my employer!"
brindley@ECE.ORST.EDU (Mike Brindley) (03/28/91)
In article <20144@cbmvax.commodore.com> hood@cbmvax.commodore.com (Scott Hood) writes: > >Make sure that you first try the fine-tuning adjustment for the A3000's >display enhancer as per the user's manual. Sometimes if the fine-tuning >is just on the edge of correct operation, you can experience a jittery >display (horizontal only). > I'm having what I believe to be the same problem; I'll try to describe it in more detail. When powering up my A3000-25 (stock), random scan lines will be momentarily shifted horizontally (mainly to the right). The problem eventually dies out and only occurs if the machine has been turned off for several hours (like over night). The display enhancer is probably not the culprit since the same thing happens when powering up with the display enhancer disabled. Turning on the monitor up to 20 minutes before hand does not seem to make any difference (the monitor is a C= 1950). The problem is so bad, that it was several weeks before I figured out what the yellow text which flashes on the screen (loading kickstart and rebooting system) says. This is a most annoying problem and is especially embarassing when trying to show off your fancy new computer to friends and family. I tried to adjust the display enhancer, but the video test patterns are all perfectly stable, so I didn't change it. On a slightly different note, why do the colors change when I put the workbench into a Superhires mode(1280x200/400) using preferences? I'm using the default WB colors (black, white, gray, and light blue); when I change to Superhires, the light blue becomes a sea green. Thanks for any help or suggestions you might have. --> Mike Brindley brindley@ece.orst.edu
jpotter@ucs.adelaide.edu.au (Jonathan Potter) (03/28/91)
My 3000 does exactly the same thing - for the first few minutes after bootup (when it is cold), random lines will jump left & right. I have been told that it is a fault Agnus chip, and this seems likely, as it only happens when there is actually something being displayed on the screen (like text output). It goes away after a few minutes (presumably when Agnus heats up) so I assume it is a heat fault. Try changing the Agnus chip and see if that makes any difference. It doesn't bother me all that much as it never lasts for more than 5 minutes at the most. Jon -- | Jonathan Potter | | Life is like a piece of | | P.O. Box 289 | jpotter@itd.adelaide.edu.au | spinach... | | Goodwood, SA | FidoNet : 3:680/829 | | | Australia 5034 | | Sort of green and wrinkly |
hood@cbmvax.commodore.com (Scott Hood) (04/03/91)
In article <2709@sirius.ucs.adelaide.edu.au> jpotter@ucs.adelaide.edu.au (Jonathan Potter) writes: >My 3000 does exactly the same thing - for the first few minutes after bootup >(when it is cold), random lines will jump left & right. > >I have been told that it is a fault Agnus chip, and this seems likely, as it >only happens when there is actually something being displayed on the screen >(like text output). It goes away after a few minutes (presumably when Agnus >heats up) so I assume it is a heat fault. > >Try changing the Agnus chip and see if that makes any difference. It doesn't >bother me all that much as it never lasts for more than 5 minutes at the most. > >Jon >-- >| P.O. Box 289 | jpotter@itd.adelaide.edu.au | spinach... | >| Goodwood, SA | FidoNet : 3:680/829 | | >| Australia 5034 | | Sort of green and wrinkly | I would sugest that you FIRST try the fine tuning adjustment in the A3000's user manual because I am fairly sure that it is the fine tuning adjustment that is just on the hairy edge of being stable and not having any pixel jitter. This is most often seen at power up when the pixels coming out of Denise are not exactly where they are being sampled by the display enhancer after the system gets warmer. You should be able to fine several "sweet" spots in the full 15 turn range of the fine tuning control where you get no pixel jitter, either cold or warmed up. Please try this and see if it helps your problem. Regards, Scott Hood -- -- Scott Hood, Hardware Design Engineer (A3000 Crew), Commodore-Amiga, Inc. {uunet|pyramid|rutgers}!cbmvax!hood hood@cbmvax.cbm.commodore.com "The views expressed here are not necessarily those of my employer!"
baxter_a@wehi.dn.mu.oz (04/06/91)
> > I would sugest that you FIRST try the fine tuning adjustment in the > A3000's user manual because I am fairly sure that it is the fine tuning > adjustment that is just on the hairy edge of being stable and not having > any pixel jitter. This is most often seen at power up when the pixels > coming out of Denise are not exactly where they are being sampled by the > display enhancer after the system gets warmer. You should be able to > fine several "sweet" spots in the full 15 turn range of the fine tuning > control where you get no pixel jitter, either cold or warmed up. > Please try this and see if it helps your problem. > > Regards, > Scott Hood What about this one... I've seen a 3000 that looks okay through deinterlacer on a VGA monitor, but in productivity, the screen is shimmering. Regards Alan
fastdial@insider.zer.sub.org (04/07/91)
HOOD%CBMVAX.COMMODORE.COM writes on 02.04.91 at 22:33 about `Re: Jittery A3000 Video`: >I have been told that it is a fault Agnus chip, and this seems likely, as it >only happens when there is actually something being displayed on the screen >(like text output). It goes away after a few minutes (presumably when Agnus >heats up) so I assume it is a heat fault. No, it isn't ! I'm using an A2000 including Big(brother)Agnus (8372A). I updated this vhip a few month ago and I had this problem with my old and now with my new chip too. My problem is also a litte bit more extremly: my Amiga not only makes some jokes with the display he gurus !! So I'll say this must be another problem, for exaple the oscillator ! Perhaps Como uses some cheap ones. And perhaps some of them didn't be so tolorant as others in this cold state ?! Or what do you mean about this, Dave ? So long FastDial ** MyBBS V1.7g Four-Wheel-Drive just means getting stuck in even more inaccessible places!