Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: hutch1980 on July 24, 2006, 06:17:04 pm
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I recently bought a used wells-gardner 19k4625 for my jamma rig and when connected to any of my jamma boards, the image is upside down. So i figured to swap the green & yellow wires which should designate the vertical (while red & blue designating horizontal, but didn't touch those) on the yoke of the tube to flip the vertical image, and that only resulted with just a bright green screen with scan lines (adjusting the vertical pot does nothing). I flipped the wires back to make sure i didn't damage anything, and it works fine except image being upside down of course. Now it being a test rig, doesn't really matter too much, but it's been bugging me on why that wouldn't work. I've done it several times on televisions with no problems.
I've done a few different searches here on the subject and found some info to try and i've got the manual/schematics for it, but nothing i could really find was usefull.
So my question is, has anyone else run into this sort of problem?
I'll try and get some pictures uploaded to show what i'm talking about.
I'm going to continue to tinker with it and maybe through trial & error i'll figure it out. Maybe there's something i'm overlooking.
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three ways to fix this,
1-turn the tube round
2-adjust the game board switches on picture flip
3-you have to reverse each pair of wires on the scan coils,red to blue/blue to red and yell to green/green to yell
number 1 is the most sensible method i think
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It sounds like you have already done the homework on this... but thought I'd throw this link to Bob's page in there for others to review.
http://homearcade.org/BBBB/yoke.html (http://homearcade.org/BBBB/yoke.html)
What you did should have done the trick. (green and yellow reversed)
But while you are tinkering around, DO NOT mix and match those other yoke pins except for reversing the "pairs" as mentioned.
I know you said it went back to "normal" after putting the yoke back where it was, but also double check the vertical plug in daughter cards, three of them, for bad solder joints or bad connections.
(just typical on those 4600's)
Maybe jarring one of those gave you a bad result when you flipped the yoke. (?)
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in the days before onboard screen flip dipswitch we had to cut all the yoke wires and use connector block to do the job
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Thanks for the help guys. I'll try your suggestions and post my results. :)
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I just thought i'd give an update.
Well, i got everything working now. Apparently, my problem had nothing to do with the yoke wires, but my bad floppy drive cable hack that connected up to the RGB Gnd Sync edge connector. I just soldered directly to the contacts and all my problems went away and my screen is now the correct orientation. Again, thanks for the help guys :applaud:
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that is not logical,how could that cause your screen to be upside down :o
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No, when i recieved the monitor, the image was already upside-down. On a seperate part of the monitor that has nothing to do with wether the image is reversed or upside-down, i had a floppy edge connecter kind of sitting on the RGB H/V pin array. My guess is that when i went to swap the green and yellow wires, i probably bumped the video connector. Moving the floppy connector around a little bit with my hand confirmed this.
So to sum it up, besides my ghetto connector, (i've since soldered my jamma cable directly to the contacts on the rgb board to remove problems) swapping the green & yellow wires together swaped the image right-side up, then swapping the red & blue wires reversed the image left to right, so doing that worked like a charm. When working on not so clean modifications, it's always good to doulbe, triple check your work to resolve all problems.
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Good deal.... glad it worked out.
I kinda figured there was something else fishy going on with it besides the yoke flip.
You an Okie too? ;)