wpl@burdvax.PRC.Unisys.COM (William P Loftus) (11/03/87)
My monitor goes POP (sounds like an electrical discharge), and the screen jumps. In addition, My machine will crash once in a while (quite a lot actually) when it POPs. Is my monitor going bad? Is there anything I can do, before bringing it into a dealer? Thanks in advance, -- William P Loftus UUCP: wpl@burdvax.UUCP Unisys/Paoli Research Center ARPA: wpl@burdvax.prc.unisys.com PO Box 517 BITNET: 202527899@VUVAXCOM Paoli, PA 19301 215-648-7222 (work) 215-649-0633 (home)
bryce@hoser.berkeley.edu (Bryce Nesbitt) (11/04/87)
In article <4754@burdvax.PRC.Unisys.COM> wpl@burdvax.PRC.Unisys.COM (William P Loftus) writes: > >My monitor goes POP (sounds like an electrical discharge), and >the screen jumps. In addition, My machine will crash once in a while >(quite a lot actually) when it POPs. Is my monitor going bad? Is >there anything I can do, before bringing it into a dealer? Dust has accumulated inside your monitor. This builds up on the high voltage lead to the tube and will arc to a nearby metal bracket. The arc can most certainly send jolts that could affect the computer. The local repair Guru, Bruce Takahasi, finds this a common problem with certain reported hard drive crashes, especially if the four daughterboard PALs have not had their grounds tied together. (The above comments apply mostly to the 1080 monitor, and the PAL chip ground is specific to the Amiga 1000) The suggested fix is to have a TV tech dust out the monitor and re-route the HV lead(s) away from anything they could arc to. Do it yourself only if you know how to take proper precautions against those very same high *latent* voltages. |\ /| . Ack! (NAK, SOH, EOT) {o O} . bryce@hoser.berkeley.EDU -or- ucbvax!hoser!bryce (") U "[The Amiga 1000 can display] up to 50 overlapping windows simultaneously." -Amiga Advertising, Spring 1987 (Yeah, thats it... *understate* the machine's capability :-( )
fnf@mcdsun.UUCP (Fred Fish) (11/05/87)
In article <4754@burdvax.PRC.Unisys.COM> wpl@burdvax.PRC.Unisys.COM (William P Loftus) writes: >My monitor goes POP (sounds like an electrical discharge), and >the screen jumps. In addition, My machine will crash once in a while >(quite a lot actually) when it POPs. Is my monitor going bad? Is >there anything I can do, before bringing it into a dealer? This subject was discussed at considerable length about a year or so ago on the net, with the consensus being that some significant number of Commodore monitors have this problem. I also have one of these, and have lived with it for almost two years now. The problem, at least as far as my monitor is concerned, literally seems to vary with the weather. Lately, my monitor has also started causing reboots, something that it never did before, which has led me to try and seek a solution. I disassembled the monitor (WARNING -- high voltage inside, even after unplugging; don't do this unless you know what you are doing), blew all the dust out of it with compressed air, clipped off all the sharp leads on the bottom of the circuit board under the HV section, and liberally sprayed the HV section with corona dope. So far, it has not popped again, but I only did this yesterday and used it for a few hours last night, so I'm not sure if it is really fixed or not. Has this problem ever been officially recognized by Commodore and an official fix and/or monitor replacement policy issued. If not, since the problem is obviously a design or manufacturing defect, it seems that C-A might be leaving themselves open for a class-action lawsuit. -Fred -- # Fred Fish hao!noao!mcdsun!fnf (602) 438-3614 # Motorola Computer Division, 2900 S. Diablo Way, Tempe, Az 85282 USA
rlucke@mntgfx.mentor.com (Rob Lucke) (11/06/87)
I`ve seen this thing before ... Monitors usually have some sort of grounding strap from the outside of the CRT tube. If this is not connected, static charge builds up on the CRT tube until it finds some convenient way to arc to ground. You hear a large *POP*, the screen jumps, and your computer crashes. This happens at varying intervals, depending on humidity, etc. Check for a properly connected ground on the monitor's CRT tube. Do this VERY CAREFULLY since high voltage may be present inside the monitor, even if it is unplugged (capacitors, static electricity, etc.). If you don't want to pay for a professional service person to do the work, at least let the monitor sit unplugged for a while before you open it (this allows the charge to "leak" off).
grr@cbmvax.UUCP (George Robbins) (11/08/87)
In article <4754@burdvax.PRC.Unisys.COM> wpl@burdvax.PRC.Unisys.COM (William P Loftus) writes: > My monitor goes POP (sounds like an electrical discharge), and > the screen jumps. In addition, My machine will crash once in a while > (quite a lot actually) when it POPs. Is my monitor going bad? Is > there anything I can do, before bringing it into a dealer? The "popping" can be caused by electrostatic discharge within the monitor case. The solution I'd recommend is to take it to a TV repair shop where they can blow out the dust, wipe off the black slime that accumulates on charged surfaces, trim off any pointy solder joints and spray the works with insulating "corona dope". None of this is particularly complicated, but don't even think of doing it unless you have the proper training and experience. Open the cover and you could either receive a fatal shock or be sliced up by an imploding picture tube. -- George Robbins - now working for, uucp: {ihnp4|rutgers|allegra}!cbmvax!grr but no way officially representing arpa: out to lunch... Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
fnf@mcdsun.UUCP (Fred Fish) (11/09/87)
In article <2702@cbmvax.UUCP> grr@cbmvax.UUCP (George Robbins) writes: >The "popping" can be caused by electrostatic discharge within the monitor >case. The solution I'd recommend is to take it to a TV repair shop where >they can blow out the dust, wipe off the black slime that accumulates on >charged surfaces, trim off any pointy solder joints and spray the works >with insulating "corona dope". None of this is particularly complicated, I've done all this myself, and the monitor still pops, though not as frequently and it no longer crashes the machine. So now I'm back to where I was a month or two ago before the problem got really bad. I guess maybe my next step is to take it to a TV repair shop and let them check the HV section to see if maybe it is set too high (is it even adjustable, some monitors are, some aren't...). -Fred -- # Fred Fish hao!noao!mcdsun!fnf (602) 438-3614 # Motorola Computer Division, 2900 S. Diablo Way, Tempe, Az 85282 USA
stever@videovax.Tek.COM (Steven E. Rice, P.E.) (11/09/87)
In article <1987Nov6.092619.136@mntgfx.mentor.com>, Rob Lucke (rlucke@mntgfx.mentor.com) writes: > [ comments about causes of monitor popping ] > Check for a properly connected ground on the monitor's CRT tube. Do > this VERY CAREFULLY since high voltage may be present inside the > monitor, even if it is unplugged (capacitors, static electricity, etc.). > If you don't want to pay for a professional service person to do the > work, at least let the monitor sit unplugged for a while before you > open it (this allows the charge to "leak" off). PLEASE be careful if you follow this advice!!! Leaving the monitor sitting unplugged "for a while" can be deceiving. The CRT can retain several thousand volts for days or weeks! Worse, if you ground the CRT anode (the cap on the side of the tube) and then remove the ground, a phenomenon known as "dielectric absorption" can cause several kilovolts (several thousands of volts) to reappear within a few minutes of removing the ground. If you feel the need to perform this operation, do these things: 1. Have someone trained in CPR in the room with you. Chances of fatal injury are small, but it is better to be safe than buried. 2. Situate the monitor on a flat, insulating surface. (Make sure it is stable -- you don't want to have it fall over on you or on the floor if a shock should cause you to move suddenly!) Do not use a table with a metal edging or other exposed metal surfaces, so you do not become part of a path for current flow. 3. CAREFULLY ground the CRT anode to the monitor chassis as soon as you have the case open sufficiently to do so. Use reasonably heavy wire with a clip that attaches securely to the chassis and a flat, spring- loaded slide that can go under the rubber anode cap and maintain contact with the anode terminal for the duration of the procedure. (The flat slide must have an insulated handle so you don't have to hold it as it comes into contact with the high voltage.) 4. Before touching the ground strap, ground it (and any other ungrounded metal) to the chassis using an insulated wire. Leave the anode ground in place until the last possible moment. Remove it from the CRT first. Then take the clip off the chassis. These precautions are not guaranteed to prevent injury (nothing is fool proof, since fools are so ingenious), but they do reduce the risks. Steve Rice ----------------------------------------------------------------------------- new: stever@videovax.tv.Tek.com old: {decvax | hplabs | ihnp4 | uw-beaver}!tektronix!videovax!stever