- Reviewing a cheap CRT degaussing wand - 2 Updates
- Commodore 1084S monitor - 5 Updates
| Mike Coon <gravity@mjcoon.plus.com>: Jan 18 10:25PM In article <DKydnb5sGf25T5n9nZ2dnUU7-IWdnZ2d@giganews.com>, spam@flippers.com says... > > On Sunday, January 17, 2021 at 12:34:53 AM UTC-5, palli...@gmail.com wrote: > >> whit3rd wrote: > > I can envision some Einstein attaching a magnet to a drill with cellophane tape, and watching in stunned horror as the magnet flies off and smashes the glass top coffee table.. > Or explodes the picture tube! > John :-#(# I used to walk to school (in the 1950s) beside a canal in Bristol (UK). There was a girder footbridge over this canal, and small kids had somehow acquired duff CRTs and would carry them half across this bridge in order to watch them smash into the water. Happy to say I never actually saw a child burst one on the girders... |
| Phil Allison <pallison49@gmail.com>: Jan 18 04:39PM -0800 Mike Coon wrote: ============= ------------------------------- ** One saw a pic of a B&W picture tube that had imploded. The electron gun had been propelled though the screen and imbeded itself in the back of a lounge chair. There is almost 20,000lbs of pressure on the out side of a 23inch one.. ...... Phil |
| George Alibinisis <george.alibinisis@gmail.com>: Jan 18 10:24AM -0800 On Monday, January 18, 2021 at 4:48:11 PM UTC+2, Peter W. wrote: > You do need to know that the position of Village Idiot is occupied by an Australian at this time. Much as you might wish to compete, your status will remain "incurably stupid", only. You may re-apply should the incumbent leave. Get a life Peter instead of running stupidity contests in Google groups especially when you are the undisputed heavy weight champion. No way for the rest of us to win. |
| "Peter W." <peterwieck33@gmail.com>: Jan 18 11:03AM -0800 > On Monday, January 18, 2021 at 4:48:11 PM UTC+2, Peter W. wrote: > > You do need to know that the position of Village Idiot is occupied by an Australian at this time. Much as you might wish to compete, your status will remain "incurably stupid", only. You may re-apply should the incumbent leave. > Get a life Peter instead of running stupidity contests in Google groups especially when you are the undisputed heavy weight champion. No way for the rest of us to win. George: Then you are in full competition with Phil for the position? He may be relieved to know that. |
| George Alibinisis <george.alibinisis@gmail.com>: Jan 18 12:03PM -0800 On Monday, January 18, 2021 at 9:04:00 PM UTC+2, Peter W. wrote: > > Get a life Peter instead of running stupidity contests in Google groups especially when you are the undisputed heavy weight champion. No way for the rest of us to win. > George: > Then you are in full competition with Phil for the position? He may be relieved to know that. you re not funny dude |
| Rayner Lucas <usenet202101@magic-cookie.co.ukNOSPAMPLEASE>: Jan 18 11:52PM In article <0e0fec2f-f1b4-4459-9168-b7824e991a09n@googlegroups.com>, george.alibinisis@gmail.com says... > Now I have posted lots of pics and info in this thread. I have already > recapped the monitor and done a lot of measurements. > https://www.edaboard.com/threads/commodore-1084s-monitor-with-faint- vertical-lines.396322/ > I thought I'd also ask here as Alex faced the exact same problem. It's odd to see such an old thread get resurrected, but it is still a relevant post even if the original participants are no longer reading, so in this case I don't think it's anything to get worked up about. I see from that edaboard thread that you've already tried the most likely solutions :-( The slowly drifting *horizontal* lines you mention sound like hum bars, i.e. excessive voltage ripple from the power supply making its way onto the display. If this is the case you'd see two bars on screen at once (100Hz ripple from a full-wave rectifier, on a screen with 50Hz vertical refresh) Again, by far the most common cause is a bad filter capacitor in the low-voltage power supply, but there can be other components at fault. See https://www.repairfaq.org/sam/monfaq.htm#monrwphb If you have access to an oscilloscope, you might want to check the outputs of the power supply for unusually high ripple. In particular, the output of the 12V DC regulator (IC403) ought to look nice and stable, as the regulator should smooth out whatever makes it past the filter capacitor. Obligatory safety note: be very careful and don't work alone, these things have some nasty voltages inside them (including that 125V DC power supply output). I highly recommend the safety guidelines at https://www.repairfaq.org/sam/monfaq.htm#montrbs Rayner -- Big-8 Management Board: https://www.big-8.org Homepage: http://magic-cookie.co.uk |
| George Alibinisis <george.alibinisis@gmail.com>: Jan 18 04:15PM -0800 On Tuesday, January 19, 2021 at 1:52:36 AM UTC+2, Rayner Lucas wrote: > -- > Big-8 Management Board: https://www.big-8.org > Homepage: http://magic-cookie.co.uk thanks for all your efforts Rayner. I am using a 1:1 isolation transformer when I power up the monitor and I do have an oscope. Ill test the PSU although the lines are many more than two.. maybe 7-8 drifting to the bottom of the screen. Thing is that there are brand new caps everywhere. I read around the internet and there was this thread and just one more guy with same monitor, same issue. He told me on eab boards via private message that his monitor is with an expert at the moment. it definetely looks like some harmonic but my knowledge in CRTs is very little at the moment - learning every day. |
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