You may have bad caps, a bad color transistor, or worse a gun gone bad.
Try reseating the RGB connector.

Make sure it it unplugged from wall outlet prior to working on it and make sure to discharge the high voltage.

It is possible to replace the CRT with an LCD monitor. I think there's at least one company selling a turnkey package, and you can find discussion online about a full DIY route as well. The trickiest part is finding an LCD screen that has an input compatible with the CGA video from these machines.

Whether this would fix your problem depends on where the problem is. It may or may not be a problem in the monitor itself.

I am curious to see how your efforts turn out. Please do keep this thread updated.

I have a SWE1 P2K, bought it brand new, the green channel on the video started going flaky after I'd had it a year or so. At first, it was just once in a while, but now it almost never comes on. Because of the intermittent nature, I assume there's a loose connection somewhere, though because once it comes on during a session of playing it stays on, it could also be a failing/failed capacitor somewhere. I've been neglecting my whole collection for the last 20 years (various life stuff), but now that I have more time to fiddle with the machines, I'm interested in getting this issue fixed. Your message is the first one I've ever seen even describing a problem similar to mine, and I've been doing web searches on the topic now and then for the last ten years or so.

Finally, someone (maybe) in the same boat I'm in!

As other's have suggested, make sure your RBG connector is making good connection by unplugging it and plugging it back in.

The television part of your game consists of the CRT (Glass tube) and the chassis (circuit board).

The chassis has the big board (the actual monitor chassis) and the neck board (at the end of the glass tube).

The neck board sometimes gets poor connections to the glass... so be gentle here... Gently take the neck board by both sides, and wiggle it a bit. A little goes a long way here, the connector to the CRT neck gets very brittle over time. The idea is that you are getting the neck board to make better connection to the tube. Kind of re-seating it without actually pulling it off the back of the tube.

If checking the RGB connector, and re-seating the neckboard doesn't bring back your red, I have (not very often, though I wouldn't say it's rare) I have had a red potentiometer get a dead spot. So, on your neck board are various knobs, usually five of them Two of these adjust the red color intensity and 'cut off' (it's a technical thing...). I would take each of the five little knobs on the neck board and turn them very slightly clockwise, then counterclockwise back to where they were originally. This moves the wipers of the pots, and can clear a 'dead spot'.

Most likely, you have a problem with your monitor chassis, you will need to pull the chassis and send it to someone who does monitor repair, and this get's difficult.

You have a 14 inch monitor, which means that your picture tube stores about 19 thousand volts like a battery, even when power is removed. When there is no power to the game, this voltage is like static electricity, only a lot more painful. The voltage is safely underneath the suction cup with the big red wire that attaches to the picture tube.

In order to remove your monitor chassis to send it off for repair, you will have to remove the suction cup with the red wire. It has little metal clip wires under the suction cup that connect to the internal 'grid' of the picture tube.

As an experienced tech, I do this with a flat blade screwdriver and an alligator clip. I attach the alligator clip to the screwdriver, and the other end of the alligator clip to the metal frame of the monitor chassis. Then I take the flat blade of the screwdriver, making sure I'm only touching the insulated plastic handle of the screwdriver, and wigggle it under the edge of the rubber suction cup. It will almost always make a 'snap' sound when the tube has been discharged. After the 'snap' or after you've made contact with the metal blade of the screwdriver to the wire clips under the suction cup, you can use the screwdriver to lift up the rubber cup and move the wire clips left and right to get them out of the hole in the side of the picture tube.

There is life-taking risk here. Though this is just 'static electricity' if you have your game unplugged, if a significant shock catches your heart rhythm at exactly the wrong point in it's cycle, a shock while doing this procedure can kill you.

You may want to get an experienced technician to do this for you. Anyone who has done TV repair can do this safely.

Once you've got the suction cup with the red wire disconnected, take pictures of how all the other wires connect to the board, and remove the chassis and neck board from the CRT Tube. The neck board frequently has a little glob of silicon rubber that is gluing it to the CRT neck, I cut that with a razor blade to make it easier to pull the neck board straight backward off of the tube.

There are several wires and at least four screws involved in taking a monitor chassis off it's frame and CRT. Take lots of pictures.

Once you have the monitor chassis and neck board (and possible control board, if your CRT has that on a remote cable, some do, some have the controls on the monitor chassis...), bubble wrap carefully each piece (Monitor Chassis, Monitor neck board, Monitor remote control board) in bubble wrap and send it to:

http://www.pnlvideo.com/

They do my monitor repair. Reasonable rates. Most things that they work on are about a hundred dollars to get it serviced and shipped back, but my shipping to California is $30-$40, so you could be looking at $150 or more to get this fixed.

Of course, if you can find someone local to look at your monitor chassis that would be cheaper and better... but the skills and parts to do this kind of work have become very rare. I do some stuff, I send most monitor chassis to PnL... even ones that are just missing a color.

Reminder/warning... as Chad stated, make sure the machine is unplugged when working on P2K monitors.
The HV tripler on the CRT chassis in the head, is deadly voltage.

CRTs are special little demons, always hard to know what might have gone wrong without some poking. And honestly I suggest that if you don't know how to discharge a CRT safely that you severely limit your poking.

That said, I've fixed a missing color by reflowing the pins on the back of the neck board, it's not rare for a cold solder joint to appear there and lose a color.

Pete_d,

Your problem is a cracked solder connection, and finding it and reflowing the solder will make your monitor reliable. (Of course, it could be more than that, monitors can have weird problems, that's why my advice to send the monitor chassis off to California for repair is the backup strategy for your problem.)

Make sure your game is unplugged. The neck board is usually held in place by a glob of silicone glue, I cut this with a razor blade and then I can gently pull the neck board off of the CRT.

Examine all the solder connections VERY CLOSELY. Use a magnifier. Resolder the connections you find are cracked or grainy with heat.

Replace the neck board and see if you have solved the intermittent problem. If you have, I unplug the machine and put a dab of silicone glue on the neckboard connection to the CRT, and you should be good to go.

If the cracked solder isn't on the neckboard (50/50 chance), you'll need to pull the chassis out and examine the circuit board for cracked solder connections. This will be right where the wires come in to the chassis carrying the RGB signal, or where the wires go from the main chassis board to the neck board. Something will likely have cracked solder connections. Re-solder and you should be good to go.

Though this is a little awkward, you COULD pull both the monitor chassis and the neckboard and access the solder side of the boards without removing the suction cup with the red wire. As an experienced technician, I'd just discharge the monitor and pull the chassis out to make it less awkward, but I think you could do your soldering and get the monitor chassis board and the neck board back in place without messing with the red wire and it's danger.

As always, and especially when dealing with CRT monitors, if you can find a technician to do this for you it would be the preferred option.

Thanks for the advice. I feel reasonably comfortable handling the work.

Unfortunately, while I don't have any particular objection to hiring out work like this, in my neck of the woods it's hard enough finding someone to clean my gutters, never mind track down a technician with the competence to work on delicate, obsolete electronics (or even modern electronics, for that matter). All too often, even if I find someone who says they can do the work, it turns out that they do a sloppy or outright incompetent job, not up to my standards. Easier to just take my time and fumble through things myself.

At least if I screw it up, I didn't charge myself an arm and a leg to do it!

Actually you have a retro tech right in your city with a great rep:

https://soundretro.co

Just an option.

My HV combiner lets you use any VGA monitor in Pin2K. Visit my web site (https://www.kahr.us) and look at the third item:

Pinball 2000 H+V Video Sync Combiner kit

-Rob
-visit https://www.kahr.us to get my daughterboard that helps fix WPC pinball resets or my re-engineered Type 1 sound board for classic Williams games

Thanks. I don't literally live in Seattle, but it's nice to know about the tech if I'm willing to make the drive.

Wow, nice! And btw, I love your daughterboard for resets. One of the favorite things in my toolbox!