Wells Gardner 19K4900 with vertical collapse

smalltownguy2

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K49xx or K4900 - vertical collapse. Just did a cap kit, reflowed yoke connector pins, video input pins, Q302 and Q303 pins, and reflowed the sand resistors in the rear corner. I'm pretty sure I have (a) failed component(s) in the vertical output area.

Can anyone give next steps on what to do? Should I pull Q302 and/or Q303 and test them using the diode test on my MM, or can I just test them on the board?

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q302 and 303 is a good start, did you have vertical collaspe b4 the cap kit. if so check for hairline cracks in that area or cold solder joints.
 
The collapse was there before I started the cap kit.

Replaced Q302 and Q303, as well as IC501, testing between each component replacement.

Metered the resistors, and they are ok.

Reflowed a lot of joints.

Still no change.

I need to see a picture on this tube to rule out any issue with the tube and/or yoke.

The tube and yoke are from a 19K5603 chassis which smoked the flyback, but putting the K5603 and the K4900 next to each other, they appear identical, so I figured the tube would be an OK candidate to drop in another 4900. Perhaps that's my error? Is the 19K5603 a medium resolution chassis? Would that matter?

I have a 4900 in my Ms Pac, so I can pull it and test the chassis on that tube I guess. I will also test the 4900 from my Ms Pac on this tube from the 5603 to make sure my tube/yoke is OK.

Just keep following traces around? Try to find a broken connection somewhere?
 
I'd do the swap and test that its not a compatability issue first.
 
The yoke is NOT compatible. You are not looking at vertical collapse although it would seem like it. Check out the wave, vertical collapse would be a solid straight line.
 
Hm.....OK, so this K5603 IS in fact a medium resolution chassis...interesting, since it appears the monitor came out of a game that was originally a CPS2 game. Didn't think that CPS2 could use a medium rez chassis, but maybe I'm wrong.

OK, then it's gut check time - the K5603 chassis that was paired with this tube has a blown blyback. It has matching numbers to the fly on the 4900 chassis. OK to swap? I tested the HOT and it's not shorted, nor is the fuse blown.
 
I'm still confused by my original picture. This monitor was found in a JAMMA cab that was missing the boards. It was found in a Dynamo cab with Neo Geo dressing.

I didn't think that Neo Geo ran with Medium Resolution? I'm still not sure that the 19K5603 IS a medium resolution monitor. The only information I could find was from an older thread here:

http://forums.arcade-museum.com/showthread.php?t=7839

Ken Layton apparently looked at some pics of the monitor chassis and told the OP that it was a medium rez version of the K4900.

Does anyone know anything about the K5603?
 
A vertical collapse could be from resistor R313 going open. This one is 470 ohm at 7 watts. Usually need to unsolder it to check it though.
 
Thanks, guys, for the all the help. I appreciate it.

I didn't trust my late night trace inspection last night, so I went over the chassis again, wiggling all pins all the way to the yoke pins. When I got to the yoke pins, I got nervous. I pulled out the meter and tested continuity from the pins through to the board. One pin was good, the other was not. BINGO.

I HAD re-soldered the pins, but obviously there was old solder beneath, because my added solder did not fix the joints. I sucked all of the solder off, resoldered all 4 pins and was greeted with this on my tube:

CIMG5730.jpg


Well, at least I fixed the deflection problem anyway. But alas, this tube's yoke is DEFINITELY for a medium resolution chassis. So, I'll have to pull this yoke and install one that's compatible with this chassis.

For kicks, I took the chassis downstairs to my game room and dropped it into my Ms Pac, which has a 4900 in it too. Unfortunately, my Ms Pac is using an early version 4900 (023) board, so the yoke is an early version yoke. I got foldover on the image that can't be adjusted out. But the part of the image that I COULD see was freakin' BEAU-TI-FUL.

FYI - BIG thank you to Peale for putting this info out there, it was very helpful:

http://forums.arcade-museum.com/showthread.php?t=142056

Without actually SEEING a perfect image, I'm pretty sure this chassis is working just fine. I have one more 4900 in the Neo Geo on location at the pizzeria, so I'll go have a look at the board in that one, and if it's a match to this chassis, maybe I'll test the chassis in there to make sure everyting is A-OK, but I'm pretty sure this chassis is good to go.

So, long story short: cold solder joints on the yoke connector pins for the vertical.
 
I stand corrected. The yoke that was on that tube WAS compatible. I got some good adjustment advise from Modessitt.

I was able to adjust the monitor to arrive at a perfect picture. Looks great in my Neo Geo cab now. I'll shoot a pic later this week and update this thread.

Thanks everyone!
 
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