Ms Pacman Monitor?

cooljjay

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Ok, I should have ordered my monitor when I first got the machine but it moved to the back of the restore stack. I went today to order one from Betson but they no longer carry CRT's. I don't think replacing capacitors in my monitor will help as there is a dead spot in the left hand corner. Anyone have an idea on where to get one?
 
I don't know what you mean by "dead spot", but if you give us some more information on the monitor, we can help you repair it. For example, what kind of monitor is it? Do you have a picture of what it's doing?

Also, if you fill in your location in your profile, there may be a KLOVer nearby with an extra monitor to sell. You can also post a WTB in the trading section.

-Ian
 
If you want a new monitor, we can help you, but you're gonna pay close to $200.

If you want to fix yours, you can do it for probably one fourth the cost or less.

Can you please give us:

-The model number of the monitor, or a picture of the back of it (focus on the circuitboard)
-A picture of the 'dead spot' you're referencing
-Your level of willingness to dig in and work on it yourself, versus your level of 'hands off'
 
I am very comfortable replacing and checking electronic components/circuitry. As a hobby I restore older tube audio equipment. The model of the monitor is Wells Gardener 19K4906. As you can tell the machine has other problems besides the monitor. Everytime I move it seems like it gets worse. I was just hoping to start with a working monitor then move to the board. But any commits on the problem is helpful. Theres a picture of the dead spot when I had the glass removed and one from just a few minutes ago. The monitor is still covered in gunk and filth, I will try to pull it, clean it and get a photo of the circuit board. If you guys think this one can be saved, I will save it but I wouldn't mind spending 200$ on a new monitor. I only have about 350$ in the machine.


snfck9.jpg

2lwtcb9.jpg
 
You're right, there ARE other issues going on there, but yes, I'm inclined to say that your tube is shot. I've never seen a chunk of the screen grid just 'missing' like that. Perhaps a rejuvenator could assist, but if you don't own one, it would probably be just as easy to replace the tube.

Replacing the tube won't solve the other issues you're having, though. It's hard to tell without a video, but it appears there's sync issues with that monitor's chassis. Possible a 'lytic capacitor has fallen out of value. Do you know if this chassis has ever been recapped? If not, it won't hurt to do it. The 19K49xx is pretty easy to work on.

Do you know anyone who has another monitor that you can hook up to your PCB? And on the flip side, it would be nice to hook your monitor up to a known working PCB to see what the output does on that one. That could rule out any other monitor chassis issues. If you get the same scrambled image on a known working monitor, then you know it's an issue with the PCB. If you get the same scrambled image on a working PCB, then your monitor's chassis has 'issues.'
 
The monitor actually seems to be working more or less properly. The "black spot" looks like just a warped raster not filling the screen completely. There is a cap that is tucked down between the connectors of one of the cards that, when faulty, causes some wicked curl on the screen at the edge.

I can see that you have a screen full of garbage, but does the game make any sounds?

Do you have another game you can connect the monitor to? If so, hook this monitor to the other game, and see if you can get a stable picture.

-Ian
 
You're right, there ARE other issues going on there, but yes, I'm inclined to say that your tube is shot. I've never seen a chunk of the screen grid just 'missing' like that. Perhaps a rejuvenator could assist, but if you don't own one, it would probably be just as easy to replace the tube.

The tube is fine. There is no way for a picture tube to fail such that a corner goes black.

-Ian
 
The tube is fine. There is no way for a picture tube to fail such that a corner goes black.

-Ian
Oops, my mistake if that's the case. I seem to remember somewhere reading about a chunk of the phosphor screen grid inside a CRT falling away once. Maybe I was smoking something.
 
Oops, my mistake if that's the case. I seem to remember somewhere reading about a chunk of the phosphor screen grid inside a CRT falling away once. Maybe I was smoking something.

It's *possible* to have a black dead spot on a tube. But the only way to cause it is to concentrate the beam there long enough to completely burn away the phosphor. As such, it's only going to happen in the very center of the screen (as caused by delfection failure). It's actually fairly common on vector monitors, and the biggest such mark I've ever seen was the size of a quarter. Usually it's tiny, smaller than a dime.

But to have an entire corner missing? That's just not possible for a normal failure to cause this. Sure, you could build a circuit to drive the deflection like that and then leave it for a week to eat away the phosphors, but that is rather unlikely.

The monitor actually looks pretty close to working. I think the game board just isn't producing a usable sync, and the thing is so far out of whack that it looks like that.

-Ian
 
Well if you guys think that replacing all the capacitors will cure the black spot, I am will to try caps are so cheap, end up spending more on shipping then the actually parts.

I unfortunately don't know of anyone else who has a working monitor or PCB to check mine. It would help if I did. I pretty much have to decide what to work on first monitor or PCB. Since the black spot was on the monitor I decided to start on that.

The machine does produce sound and ms pacman moved back and forth, heard her eat the ghost and visa versa. Heres a video of it before I moved and put it on the back burner.

http://www.youtube.com/watch?v=yrx2wBgD5sk
 
OK, so you can hear all the game sounds, it coins up and you can play it? For some reason I was thinking it was dead.

I assume you've already tried to adjust the monitor, correct? I mean, from the pictures it looks like the sync is way out of whack - can you get it to dial in any better with the horizontal hold and frequency controls? Don't forget L351.

The 4600 is a very solid monitor, but they can be a bit annoying to get working again. Usually with those I take them apart, replace all the caps, and reflow all the solder joints at the card connctors, both at the card and at the chassis.

-Ian
 
Ahhhhh.....the plot thickens. Thanks for the video, that helps.

Looking at the garbage on the screen, I see zeros in the garbage. I'm thinking PCB issue. Yeah, that's my vote.

Until you can test this monitor on a known working PCB, it's going to be hard to continue to assist you further.
 
Ahhhhh.....the plot thickens. Thanks for the video, that helps.

Looking at the garbage on the screen, I see zeros in the garbage. I'm thinking PCB issue. Yeah, that's my vote.

Until you can test this monitor on a known working PCB, it's going to be hard to continue to assist you further.

Yep it has big time issues. I just pulled it and start pulling chips, in the event that cleaning and resetting will bring things back up. But it appears about a half dozen chips are toast due to moister aka cancer known to all by rust most of the pins just fell off once cleaner was applied...guess its time to hunt down a good board...in the mean time I can spend the time cleaning the billions of paint splatters off the cabinet.
 
If you're talking about millions of little blue dots all over the side art, that's factory, and SHOULD be there. All Ms Pac cabs have the spatter.
 
If you're talking about millions of little blue dots all over the side art, that's factory, and SHOULD be there. All Ms Pac cabs have the spatter.


I wish these are millions and millions of tiny white dots....on everything from the joy stick to the kick panel. Heres a pic.

33cyf0y.jpg

b89uvq.jpg
 
HA got to luv my luck, some how I got the board to work...the maze is just a little yellow from the bad chips but hey its playable. But the monitor has some really bad burn in, visible when playing too. Don't think recaping will remove the burn in.

msivrr.jpg
 
Yeah, the only way to get rid of screen burn is to replace the picture tube.

But, a cap kit will do wonders for that picture - the faded lines toward the top of the screen, for instance. The black blob is odd. At first it just looked like a warped image, but now it's clear that something else is at fault. I've seen a similar fault on a television set once, it was a faulty voltage regulator. Check the B+ voltage, see what you get. Also, does the blob move or change at all if you leave the monitor on for an hour or so?

I'd start by recapping the monitor, then see where your voltages are at. Once you get the caps out of the way, troubleshooting that blob will be easier. Also, if the screen burn is bad enough that you can't live with it, you can start tracking down a replacement picture tube. I usually just scavenge them from old TV sets, but you might also be able to find a used 4600 tube with less burn if you post in the WTB section (or a complete monitor, for that matter).

-Ian
 
Also, does the blob move or change at all if you leave the monitor on for an hour or so?

I'd start by recapping the monitor, then see where your voltages are at. Once you get the caps out of the way, troubleshooting that blob will be easier. Also, if the screen burn is bad enough that you can't live with it, you can start tracking down a replacement picture tube. I usually just scavenge them from old TV sets, but you might also be able to find a used 4600 tube with less burn if you post in the WTB section (or a complete monitor, for that matter).

-Ian

I haven't let the monitor run for over an hour, but as I've been using it, it hasn't changed places. I think I will recap the monitor as it is pretty cheap for caps, then I will see how bad the screen burn is. As you say it will do wonders for the picture, so I imagine it will be brighter and the burn not as noticeable. Then I will post a wanted ad, just wish the new monitors were being banned. With the recap lets hope the strange blob will go away.
 
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