Arcade machine monitor question.

[Mishran]

Some of you may remember the Centipede turned MVS cab I posted pics of a few months ago. Well I had to replace the monitor tube recently and having checked yoke impedence and neck board pins, it seemed to match the old tube. After hooking the thing up I got the above pictured image on the tube. It's the MVS cross-hatch screen, just really jumbled. The lines jump around, but remain centered on the screen, the image never touches the top or bottom.

This is my first tube replacement so I'm not really sure how to progress as the connections are all solid and the chassis components appear to be in decent condition stil. If anyone has an idea what I may try to fix the display, would be much appreciated.

[BlueBMW]

Ill assume youve tried some of the various geometry adjustments on the monitor?

[Mishran]

Yes I have. I was considering taking the chassis out and giving it a good examination. To make sure there are no broken solder joints and to visually check for leaky caps, bad diodes, etc.

The original tube neck was accidentally snapped off by the wife while doing something in the shed where the cab was stored. The back board was removed and I had it powered on at the time so I don't know if it may have caused a problem with the neck board or chassis. She claimed to have bumped it with a shovel handle and heard a hissing coming from the cab which was the tube decompressing.

The cab isn't worth paying to have a new or refurbished monitor installed, so I went the cheap route of installing a tube myself. If I can't get it working I'm most likely going to scrap the cab.

[rsa2000]

I know its taboo in the arcade world but before scrapping maybe decase a tv and get a rgb converter board.  This is how I did my MVS and while not as awesome as a proper monitor it looks nice with s-video. Tv + Converter about $100.  Better than playing an "audio game." 

[majors]

Never done a successful tube swap, but ppl over at  arcade-museum might have some threads with pro tips.

Since you can see a bit of the cross hatch, you at least something right The lines seem to be the blanking circuit but they usually do not jump around like in the image. Not "touching the top and bottom" could also be slightly wrong voltages/ratings. Did you swap the yoke also or just plug in the chassis to the donor tube/yoke?

I bet it was fun the first time you powered that bitch up. Did you stand behind a cinder block wall?

[Mishran]

I used the yoke that was on the tube. I used an extension cord to keep a safe distance. 

I read that neck pin count and yoke impedance were the two of the biggest factors when doing a tube swap. They both matched up, so I figured I'd give it a go.

Hooked an extra MV-1AX board that i repaired to the thing with a extra copy of magician lord and you can see the game demo run. Just don't think you can play it in that condition.

I was fixing the cab up for use with stand-alone Jamma boards such as my POW board, but if I can't figure this out, it's going to the dump. I originally just purchased it for the MVS board and games it came with, the cab was just a bonus addition.

[BlueBMW]

I guess I got really lucky with the tube I swapped on my MVS cab.  I found a 19" TV off craigslist, checked the numbers on the tube and resistances of the yoke.  Plugged it in and whammo!  Had good picture.

[Mishran]

I'm working with an original Centipede chassis built in 1983, so some slight modification was necessary with the connector wires by splicing the new yoke wires to the original connectors in order to plug the new tube into it.

[Mishran]

Still nothing on this. Gonna try another tube to see if I can get somewhere with it. If it doesn't work, then it's going to the big arcade in the sky. Unless someone who lives in the Harrisburg region of Pennsylvania wants it. If so, come get it out of my house!