Monitor Missing Blue Color

DJMOJO

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So i just bought my first dedicated arcade machine. Killer Instinct bought it from the original owner for 350. the cabinet was never in a public arcade so it doesnt have to much wear and tear which is nice. anyway i digress, the monitor does not display blue, i was also having a hard time identifying the monitor but i believe it is a WG K7400 i see some of the capacitors have leaked out an acidy type of mess under them however they dont look swolen. the discharge kind of looks like toothpaste.

here is a video of it
http://www.youtube.com/watch?v=eeaXzJEeZeM

here is a link to the photobucket album with all the pictures for greater detail.
http://smg.photobucket.com/albums/v638/DJMOJO/Killer Insticnt Arcade/
 
that's not the caps leaking, that's glue put on to hold them in place. even when caps are installed backwards and "explode" out the top they don't leak like that.

cap kit is a good place to start; while doing it check and reflow the solder on all the header pins.
 
id check for "cold"(cracked) solder joints where the video pins hookup...

afterwards, id try to adjust the blue gains and see if theres any life left there....
 
where might the blue gain adjust be? the monitor controls that i have seen are behind the control panel. but there wasn't individual color adjustment pods on that panel. only like the v and h sync and v and h holds.
 
Could be a few things:

1) the pin may not be connecting. This has happened to me before - check the inside of the connector and see if the pin might be stuck in. You can probably re-bend it with a small screw driver. Check the pins that go into the monitor PCB first, and also be sure to check the pins on the jamma harness.

2) It could be the color circuit in the board that is bad. This is usually an easy fix if your other colors are working - because the 3 color circuits are usually identical and right next to each other - and if you test the parts you will find the non-working ones vs the working ones.

3) It could possibly be the game board. You can test another board in the cabinet to make sure.

4) It could be the blue drive in the neckboard needs to be turned up. Sometimes they are turned all the way down - but this is usually not the case. Doesn't hurt to check though.
 
wow awesome so much support thanks so much for all the help im going to check it right now. can you guys definitely identify the monitor based on the pictures in the photobucket album? id just like to be 100% sure before i order a cap kit. oh and i dont have any other boards to rule out the board being messed up.
 
comparing your photos to the one at:

http://www.therealbobroberts.net/mon70.jpg

it looks like a 7400 is a darn good possibility. you can always e-mail Bob Roberts with that model number (25k2193) and see if he can match it just to be sure.

good luck.
Cool thanks! ill email him asap

ok the only two adjustment pods were v and h sync pods wich is odd because you can also adjust that stuff on that separate control pcb.
 
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This is the only other PCB that i can see connected to the monitors main board.
 
that's the remote adjustment PCB.

the neck board is the PCB that's attached on the very end of the thin neck of the glass tube (hence "neck board".)

i circled it in this picture... not the same CRT but the neckboards are all in the same location.

neckboard.jpg
 
If your monitor IS a K7400, there should be a sticker on the board along the back left edge that (among other things) will say WG2574-whatever.

Also, those monitors are well-known for having cold solder and lifter traces around the color drive transistors on the neckboard. This is caused by the heat, and the crappy small heat sinks on those transistors. I'm willing to bet your problem is in that area...
 
wow awesome so much support thanks so much for all the help im going to check it right now. can you guys definitely identify the monitor based on the pictures in the photobucket album? id just like to be 100% sure before i order a cap kit. oh and i dont have any other boards to rule out the board being messed up.

You have a Wells-Gardner "U-2000" model.
 
that's the remote adjustment PCB.

the neck board is the PCB that's attached on the very end of the thin neck of the glass tube (hence "neck board".)

i circled it in this picture... not the same CRT but the neckboards are all in the same location.

neckboard.jpg

OOOOOH haha thanks, everyone excuse my noobishnes. this is my first arcade (i made one but it isnt a production arcade odviously).
S3010437.jpg

i adjusted the pod all the way on the left (B Bias) from end to end and it didnt turn the blue up at all, all it did is turn the screen green so i took it back to where it was. then i tried playing with the rest of the pods and they would turn the color i was adjusting off from one side to green if i turned it all the way. i set them all back to their default before i messed with them. so i guess i just gotta take out the pcb and redo all the solder. is this right?

You have a Wells-Gardner "U-2000" model.

Thanks for IDing it!
 
See those parts with the big pieces of metal attached to them just below those color pots you were adjusting? Those are the color drive transistors. Look at the other side of the neckboard while wiggling them with your fingers. if you see anything moving directly opposite of the part you're wiggling, that may be why you have no blue...
 
well i wiggled them thoroughly and i didn't see any cold solder joints or anything moving on the back of the neck board. are those pieces of metal supposed to be heat syncs?
 
Yes. Okay, then the next step is to measure voltage while the monitor is on. The red, green, and blue signals come to the neckboard by wires. Measure the DC voltage at each wire to see if all three make it that far. If you have voltage for red and green, but not blue, then the problem isn't on the neckboard.....
 
ok cool ill have to do that after i get home from work! ill also get a picture of the back of the neck board to see if im measuring the right spots.
 
I read this http://forum.arcadecontrols.com/index.php?topic=85640.msg898346#msg898346

and basically had the same issue long story short i re-flowed all the solder on the neck board and plug it all back in but nothing seemed to change. then i took it out one more time to further inspection when i came to find this...

2009-12-13195013.jpg


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2009-12-13195005.jpg


Looks like one of the pins from the tube has broken off in the neck board... is this thing fubar? i was gonna do a cap kit but now im kind of discouraged...

let me just say im new to monitor repair, im an amature at best to electronics repair but i do have lots of experience soldering modchips on ps2s and such so i know my way around a soldering iron i supose. anyway. should i just replace this POS or is there some way to repair it? again im new to monitors and from what i hear new WG monitors arent so hot so what would be a good replacement for the 25" U2000 (its in a KI cabinet)
 
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