Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: Nipedley on September 12, 2005, 12:55:14 pm
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I thought I'd create a thread with all my current problems and what can be done to solve them.
1) Wobbly screen - Solution, Capkit I presume (correct me if im wrong on any of these)
2) Small Vertical Foldover - Capkit
3) Very rare but happens Red Tinge to screen - Red transistor, Randy Fromm's H-C short solution?
4) Very Very rare No picture at all - HV Protection Circuit so C57, IC4?
I want to know a list of all parts to replace, as I'm going to replace everything that needs it all in one when I get the chassis out in about a months time. Please let me know of any other solutions, or if anything I've said is wrong. (Especially you Ken and MonitorGuru!)
It would seem to me that the number 4 only occurs in very high temperatures - as it wouldnt work when in my shed it was about 34c, but now its about 26c and it works fine... any components that are particularly vulnerable to temperature? (Or that can be?)
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The problems I had.. First chassis had some kind of weirdo horizontal position/width thing going on, I never resolved it, despite a capkit, replacing IC1, IC2 and the width coil and HOT. I eventually found another non-functional chassis..
Blown fuse, blows fuse on power up - test/replace Q11 as per Fromm's flowchart (usually caused by running w/o iso transformer)
Picture, but a blueish screen - ie; blue gun on full blast despite adjusting drive/cutoff controls, (too much/ too little color) Q1, Q2, Q3 and Q201 thru 203 (neckboard). My problem was the neckboard. Could also be IC1.
BTW, the slight vertical foldover could just be a simple adjustment of the vertical pos/50-60hz pot, a small surface mounted pot right next to/above the horizonal hold.
This is a really great monitor once you get it functioning..
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BUMP.. anyone else have any advice?
Also, the reason I say I dont think it is a heater -> cathode short for the red problem, is its very rare, appears to occur when the signal is lost while the game is on (powered), and I see no raster lines/diagonal retrace lines or whatever you would like to call them, just a red hue over the top of the picture.. it was also my understanding that h->c shorts didnt just occur after a reset, and then go away once you've actually turned it off and then back on again..
Anyway, solutions? Advice? All appreciated
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Have you tried turning down your red cutoff or red drive?
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Have you tried turning down your red cutoff or red drive?
Well if I did do that, when the monitor was operating normally there would be practically no red on the screen.. If you mean to see if it is the transistor, well, it happens so rarely that I can never predict when it will (twice in about 2 months) and the back of the machine is unaccessible right now (my shed is small and i need the room for the repairs on my megatech machine :/ once thats done terminator is going to be completely "shopped" by myself =)). To me atleast these symptoms (very rare occurance, only seems to happen when video signal is lost (but could be coincidence doesnt happen enough for me to tell, no retrace lines visible) would indicate to me its a component failure rather than a short.. My main concern though is 4) - No picture, I assume that it is the HV shutdown circuit as I have nothing else to go on. Any ideas guys? Ken? Monitorguru?