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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: orb85750 on March 24, 2009, 05:58:25 AM
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So I purchased this (extremely yellowed) 1950-B monitor from eBay. I have an adapter to get its attached video cable to fit with an A1200. Problem is that the colors are rather whacky and cannot seem to be adjusted. The top of the screen is also a bit distorted. Any thoughts as to whether the problem is the monitor, the adapter, or something else? Anyone have experience with this model of Commodore multiscan monitor? Thanks, -Dave
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hi dave found this on the amiga hardware site
The Commodore 1950 is really a rebadged AOC CM314 with an Hitachi made tube. It is a 14" monitor which supports 15Khz - 35Khz horiztonal and 50Hz - 80Hz vertical. It has a dot pitch of 0.31.
Common Problems
A sync problem may be caused by the monitor detecting sync on the Green input and then disabling the horizontal and vertical sync inputs. Removing the 10K R854 resistor or the 10uf C812 capacitor on the small vertical board may fix this. It may also cause problems of its own, so be warned. The analog/TTL switch appears to be prone to failure. However, if switching the switch brings back the picture, it may actually be that the 74LS123 (IC805) on the same board is failing. The suggested course of action is to replace (or at least resolder) this chip first, since it's a commonly available part. A defect in the way the 74LS123 is mounted may be present; there should be +5V on pin 3, but the way the chip is mounted or the board is manufactured, it may be intermittent. There should be a PCB trace between pin 3 and pin 16, however, pin 3 is not soldered to this trace, but only friction-fit (non-plated-through holes?). When the analog switch is moved, it causes intermittent contact between pin 3 and the trace. A soldered jumper to pin 16 is an easy way to fix this, or you may be able to solder to the trace already present. Another common problem is the failure of a multifunction sync chip. Replacements should be available from Sony. The high-voltage boards may crack; this can be one cause of the monitor that starts working when you hit it. A 1 megohm resistor in the second power supply's startup circuit goes bad, causing the monitor to remain dark. Replacing the resistor with a higher wattage one may help prevent
http://www.amiga-hardware.com/
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Right, I saw that, but it doesn't seem to be quite related to the problem I'm having (?)
actung_bab wrote:
hi dave found this on the amiga hardware site
The Commodore 1950 is really a rebadged AOC CM314 with an Hitachi made tube. It is a 14" monitor which supports 15Khz - 35Khz horiztonal and 50Hz - 80Hz vertical. It has a dot pitch of 0.31.
Common Problems
A sync problem may be caused by the monitor detecting sync on the Green input and then disabling the horizontal and vertical sync inputs. Removing the 10K R854 resistor or the 10uf C812 capacitor on the small vertical board may fix this. It may also cause problems of its own, so be warned. The analog/TTL switch appears to be prone to failure. However, if switching the switch brings back the picture, it may actually be that the 74LS123 (IC805) on the same board is failing. The suggested course of action is to replace (or at least resolder) this chip first, since it's a commonly available part. A defect in the way the 74LS123 is mounted may be present; there should be +5V on pin 3, but the way the chip is mounted or the board is manufactured, it may be intermittent. There should be a PCB trace between pin 3 and pin 16, however, pin 3 is not soldered to this trace, but only friction-fit (non-plated-through holes?). When the analog switch is moved, it causes intermittent contact between pin 3 and the trace. A soldered jumper to pin 16 is an easy way to fix this, or you may be able to solder to the trace already present. Another common problem is the failure of a multifunction sync chip. Replacements should be available from Sony. The high-voltage boards may crack; this can be one cause of the monitor that starts working when you hit it. A 1 megohm resistor in the second power supply's startup circuit goes bad, causing the monitor to remain dark. Replacing the resistor with a higher wattage one may help prevent
http://www.amiga-hardware.com/
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I have the same problem with this monitor, colors seems to be weird, and it has no hue control.. gray looks like lilac or light purple, how can I adjust the hue on this monitor??
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I have the same problem with this monitor, colors seems to be weird, and it has no hue control.. gray looks like lilac or light purple, how can I adjust the hue on this monitor??
Interesting to find out that the monitor itself did not turn out to be the problem in my case, as far as I could tell. I did not get it to work properly with my A500 OS 1.3, but it did work fine once I hooked it up on an A3000 OS 2.1 (at both frequencies). I think the older OS of the A500 does not support this monitor without some type of driver/fiddling? I don't really know for sure. What Amiga computer model are you trying to use with the monitor?
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Interesting that it worked on an A3000 as that has a built in Flicker Fixer / Scan Doubler for use on normal VGA monitors, whereas all the other Amiga's don't (not sure about the A4000)
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Interesting that it worked on an A3000 as that has a built in Flicker Fixer / Scan Doubler for use on normal VGA monitors, whereas all the other Amiga's don't (not sure about the A4000)
Just to clarify, on the A3000, it worked both with the VGA port *and* with the RGB port (using my pin adapter) equally well. Of course, there's no scan doubler for the RGB port, so I think that any bizarre color issue has everything to do with the OS, but I'm not certain. Anyone else have experience with the 1950-B? I've since sold my 1950-B to a bowling ally in Canada that still uses Amiga computers for their automated scoring system!
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That's brilliant. We should start a thread on "Amiga's still being used today" :)
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Interesting that it worked on an A3000 as that has a built in Flicker Fixer / Scan Doubler for use on normal VGA monitors, whereas all the other Amiga's don't (not sure about the A4000)
A4000 doesn't have a built in scandoubler, unfortunately.
Commodore 1942, 1950, and 1960 (I believe) monitors are all multisync and support 15khz modes as well as VGA-type rates.
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I think you have a week picture tube. There is too much on the red gun, or the blue and green guns are too week. Adjusting is possible inside, try locate the r,g,b pots, normally on the panel on the tube, or near the tube wires. Sorry, i dont know this modell, i tell this generell TV/Monitor experience. Adjusting takes time, and DANGEROUS. Consult with technicians. DONT FORGET THE HIGH VOLTAGE INSIDE, WITCH EASELY KILL YOU !!!
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hi dave found this on the amiga hardware site
The Commodore 1950 is really a rebadged AOC CM314 with an Hitachi made tube. It is a 14" monitor which supports 15Khz - 35Khz horiztonal and 50Hz - 80Hz vertical. It has a dot pitch of 0.31.
Common Problems
A sync problem may be caused by the monitor detecting sync on the Green input and then disabling the horizontal and vertical sync inputs. Removing the 10K R854 resistor or the 10uf C812 capacitor on the small vertical board may fix this. It may also cause problems of its own, so be warned. The analog/TTL switch appears to be prone to failure. However, if switching the switch brings back the picture, it may actually be that the 74LS123 (IC805) on the same board is failing. The suggested course of action is to replace (or at least resolder) this chip first, since it's a commonly available part. A defect in the way the 74LS123 is mounted may be present; there should be +5V on pin 3, but the way the chip is mounted or the board is manufactured, it may be intermittent. There should be a PCB trace between pin 3 and pin 16, however, pin 3 is not soldered to this trace, but only friction-fit (non-plated-through holes?). When the analog switch is moved, it causes intermittent contact between pin 3 and the trace. A soldered jumper to pin 16 is an easy way to fix this, or you may be able to solder to the trace already present. Another common problem is the failure of a multifunction sync chip. Replacements should be available from Sony. The high-voltage boards may crack; this can be one cause of the monitor that starts working when you hit it. A 1 megohm resistor in the second power supply's startup circuit goes bad, causing the monitor to remain dark. Replacing the resistor with a higher wattage one may help prevent
http://www.amiga-hardware.com/
Thanks for posting this! I just got a Commodore 1950 with the Analog/TTL issues and did like this said and it's working great now! (solder pin 3 to pin 16 on the 74LS123 chip)
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DP
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The 1950 monitors are notorious for having problems. Expect problems if you buy one.