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Repair of old arcade monitor 1979
I've got a rare old vector arcade monitor from a "Warrior" arcade game
that came out in 1979. Everything works except that the picture is way off center. To the point that about half of it is off-screen. I've adjusted the horizontal and vertical controls as far as they go. So I'm thinking I need to adjust the yoke. But I've never done that before. I tried loosening the screw and I can rotate it which rotates the picture. But I don't know how to move it to a different angle to get the picture back in the middle. It's an old b&w monitor so I don't have to worry about color convergience or anything like that. Can someone give a novice a clue on how to go about this? Thanks! John |
Repair of old arcade monitor 1979
wrote in message oups.com... I've got a rare old vector arcade monitor from a "Warrior" arcade game that came out in 1979. Everything works except that the picture is way off center. To the point that about half of it is off-screen. I've adjusted the horizontal and vertical controls as far as they go. So I'm thinking I need to adjust the yoke. But I've never done that before. I tried loosening the screw and I can rotate it which rotates the picture. But I don't know how to move it to a different angle to get the picture back in the middle. It's an old b&w monitor so I don't have to worry about color convergience or anything like that. Can someone give a novice a clue on how to go about this? Thanks! John John: There may be, as with old B&W TV sets a couple of usually black cardboard looking circular pieces with tabs often mounted on and comprising part of the back of the yoke. Those could be rotated (gosh how rusty I am on this!) to magnetically centre the whole raster (picture)? Try that? I guess the 'black things' were somehow magnetic and steered the electron beam? There used to also be an 'Ion trap' that had to also adjusted; if it was way off the picture would show on the screen at all! IIRC the trap was to steer the electron beam/s back towards the screen to avoid ion burn? because the tube gun was manufactured not exactly pointing at the screen. The ion trap looked like a springy open metal clip around the tube neck and contained a small magnet about half the size of postage stamp. Maybe that's missing? If so try a smallish magnet to see if affects the problem. But stand to be corrected on any of this by those more knowledgeable. Terry |
Repair of old arcade monitor 1979
Terry wrote:
wrote in message oups.com... I've got a rare old vector arcade monitor from a "Warrior" arcade game that came out in 1979. Everything works except that the picture is way off center. To the point that about half of it is off-screen. I've adjusted the horizontal and vertical controls as far as they go. So I'm thinking I need to adjust the yoke. But I've never done that before. I tried loosening the screw and I can rotate it which rotates the picture. But I don't know how to move it to a different angle to get the picture back in the middle. It's an old b&w monitor so I don't have to worry about color convergience or anything like that. Can someone give a novice a clue on how to go about this? Thanks! John John: There may be, as with old B&W TV sets a couple of usually black cardboard looking circular pieces with tabs often mounted on and comprising part of the back of the yoke. Those could be rotated (gosh how rusty I am on this!) to magnetically centre the whole raster (picture)? Try that? I guess the 'black things' were somehow magnetic and steered the electron beam? There used to also be an 'Ion trap' that had to also adjusted; if it was way off the picture would show on the screen at all! IIRC the trap was to steer the electron beam/s back towards the screen to avoid ion burn? because the tube gun was manufactured not exactly pointing at the screen. The ion trap looked like a springy open metal clip around the tube neck and contained a small magnet about half the size of postage stamp. Maybe that's missing? If so try a smallish magnet to see if affects the problem. But stand to be corrected on any of this by those more knowledgeable. Terry Ion traps were a good deal earlier than 1979. You are correct about the tabs at the back of the yolk though - I think they were called 'shuffle magnets' or something like that(but my memory might be no better than yours here) - and they might well be the cause of the problem. Turning them independently of each other should centralise the raster - loosening and turning the yoke itself will only move the scan in the horizontal plane (but make sure the yoke hasn't come loose and moved away from the CRT). All this assumes that it is a monochrome monitor. |
Repair of old arcade monitor 1979
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Repair of old arcade monitor 1979
If the picture is off centre, there is obviously a component(s) that has
failed. It would be best to have the monitor properly serviced, rather than try tweaking it to compensate for an error. I am sure that the monitor originally did not have the fault you are describing. In a monitor that old, it is more than likely that there are a number of high ESR capacitors, and maybe even some resistor values that have drifted out with age, and whatever use the monitor had. -- JANA _____ wrote in message oups.com... I've got a rare old vector arcade monitor from a "Warrior" arcade game that came out in 1979. Everything works except that the picture is way off center. To the point that about half of it is off-screen. I've adjusted the horizontal and vertical controls as far as they go. So I'm thinking I need to adjust the yoke. But I've never done that before. I tried loosening the screw and I can rotate it which rotates the picture. But I don't know how to move it to a different angle to get the picture back in the middle. It's an old b&w monitor so I don't have to worry about color convergience or anything like that. Can someone give a novice a clue on how to go about this? Thanks! John |
Repair of old arcade monitor 1979
Farmer Giles writes:
Terry wrote: wrote in message oups.com... I've got a rare old vector arcade monitor from a "Warrior" arcade game that came out in 1979. Everything works except that the picture is way off center. To the point that about half of it is off-screen. I've adjusted the horizontal and vertical controls as far as they go. So I'm thinking I need to adjust the yoke. But I've never done that before. I tried loosening the screw and I can rotate it which rotates the picture. But I don't know how to move it to a different angle to get the picture back in the middle. It's an old b&w monitor so I don't have to worry about color convergience or anything like that. Can someone give a novice a clue on how to go about this? Thanks! John John: There may be, as with old B&W TV sets a couple of usually black cardboard looking circular pieces with tabs often mounted on and comprising part of the back of the yoke. Those could be rotated (gosh how rusty I am on this!) to magnetically centre the whole raster (picture)? Try that? I guess the 'black things' were somehow magnetic and steered the electron beam? There used to also be an 'Ion trap' that had to also adjusted; if it was way off the picture would show on the screen at all! IIRC the trap was to steer the electron beam/s back towards the screen to avoid ion burn? because the tube gun was manufactured not exactly pointing at the screen. The ion trap looked like a springy open metal clip around the tube neck and contained a small magnet about half the size of postage stamp. Maybe that's missing? If so try a smallish magnet to see if affects the problem. But stand to be corrected on any of this by those more knowledgeable. Terry Ion traps were a good deal earlier than 1979. You are correct about the tabs at the back of the yolk though - I think they were called 'shuffle magnets' or something like that(but my memory might be no better than yours here) - and they might well be the cause of the problem. Turning them independently of each other should centralise the raster - loosening and turning the yoke itself will only move the scan in the horizontal plane (but make sure the yoke hasn't come loose and moved away from the CRT). All this assumes that it is a monochrome monitor. Those never had enough range to cause what has been described, unless perhaps deliberately totally messed up by someone before him. --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. |
Repair of old arcade monitor 1979
Thank you all for your tips. It's good stuff. I was able to locate
the magnet adjustments but clearly there is something wrong with the electronics. Zanen doesn't appear to offer a kit for this board. It's an old Vectorbeam monitor from a "Warrior" game. And due to the rarity and obscurity of this thing I think I'm going to defer to a professional on this one after all. Thank you all for your help though! |
Repair of old arcade monitor 1979
JANA wrote:
If the picture is off centre, there is obviously a component(s) that has failed. It would be best to have the monitor properly serviced, rather than try tweaking it to compensate for an error. I am sure that the monitor originally did not have the fault you are describing. In a monitor that old, it is more than likely that there are a number of high ESR capacitors, and maybe even some resistor values that have drifted out with age, and whatever use the monitor had. That's not always true, these things quite often got fiddled with, or just mechanical vibration would muck up the adjustments, or the monitor may have come from some other game and been swapped in without adjusting it. |
Repair of old arcade monitor 1979
Go check out rec.games.video.arcade.collecting
There are quiet a few knowledgeable people over there. You might even be able to find someone to fix it for you there also.. - Mike "jhuie" wrote in message ups.com... Thank you all for your tips. It's good stuff. I was able to locate the magnet adjustments but clearly there is something wrong with the electronics. Zanen doesn't appear to offer a kit for this board. It's an old Vectorbeam monitor from a "Warrior" game. And due to the rarity and obscurity of this thing I think I'm going to defer to a professional on this one after all. Thank you all for your help though! |
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