Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: Reptilz on April 18, 2010, 01:14:35 pm
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Ive ran into a problem and was wondering if any of you guys might have some ideas on what it could be.
I bought a Dedicated MK2 Arcade with a Polo 25" Monitor. The screen had a green tint but I figured I could adjust it out when I brought it home. Once I got home and looked at it better I noticed the MK characters on the select screen where shorter at the bottom of the screen and stretched taller at the top. So I adjusted for days, using all the knobs on the neckboard, the front board and the 2 on the transistor. The size issue never changed and as for the colors, I could get the green out but then it would either be too dark or too bright and have too much red in it. Basicly it just wasn't going to get any better.
So I was talking to yourmameman a little and he said I should carefully pull the neckboard off and see if any of the pins were bent and then carefully put it back on straight. So I did, The pins looked perfect, so I carefully whiped and blew some of the dusty off the neckboard and carefully put it back on. Powered up the machine and now there is NO picture, all I get is solid GREEN. The sound and the game play perfect, and the monitor powers up, just NO image, So I went back to adjusting, cant get anything, all i can do is adjust the brightness and shrink the screen, cant bring up a picture or change the color. So I tried reseating the neckboard a few times with the same results.
What do you think happened? Anything I can try? All I can think of was my neckboard was weak to begin with and it just gave out? Anyone have a good neckboard? Please HELP!! lol. Thanks,
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you will probably find that the green drive transistor(BF859) at position T4 is short circuit,if you remove that transistor and then try the monitor you should find your other colours return but there will be no green-if this is the case then just order a new transistor and replace
Leaky drive transistor are quite common on these chassis,I have probably changed about 20 in the last 3 years
for the stretch adjust RV102 vertical linearity-its next to IC103 vertical deflection IC
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Ok, I will try removing the green drive transistor and see what happens.
As for the sizing issue, ive adjusted vertically and it doesn't even try to get better. So it has to be something else.
I'll get back with the results.
Thanks for the quick reply.
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Ok, I dont see a T4, so I took a couple pics of the neckboard. Im 100% new to this and dont want to remove the wrong thing. I see a T1, T3, T5, T7, by my green adjustment it says RV4.
Update: Ok, I think I located it, its in the back, tall flat grey and in the center of the 3.
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yep thats the one,also check for bad solder joints
if you remove that transistor you will prove the fault
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Sorry for digging up an old 1 here thought I would mention for others looking for an answer.
What I'm wondering is why your neck board looks totally different from my polo neckboard. Also you neck board is 12 pins.. Mine is 10. Wonder if that would make a difference?