Replacing an arcade monitor with a pc monitor - WG K4600 -

[akcrash]

Hello,

I managed to pick up a Galaga cab about a year ago, the cabinet is in rough shape but fixable. The game boots up but I am having monitor issues. When I got the game the whole image was squashed into a narrow line running up the monitor. By adjust the horizontal pot on the tube I was able to expand the image to about 2-3 inches. I thought maybe a cap kit would help, after I installed the cap kit nothing really changed, but about the second or third time I turned the game on after that the screen stays black now. It does not look like the tube heater is working, as the base of the tube never starts to glow.

I suspect a possible problem on the power board for the tube. But I really hate working on monitors, so I am wondering if there is a way to hook up a PC monitor to the game boards? I know there is a lot of info about using a PC on an arcade monitor, but I could not find anything about doing it the other way around.

Thanks for any input.

[northerngames]

scan converter.

 Or a used but working monitor may be the cheaper way and for sure to work route.

[akcrash]

Any ideas where to look for info about this scan converter?

I am trying to be a cheap @#$ about this, I have spent more then I planned to on my MAME cab; that and shipping for a monitor to Alaska gets spendy quick.

Thanks for any more info, off to do another google search....

[grantspain]

your monitor sounds like it has suffered from vertical frame collapse,some chassis will not power up with a fault in the frame circuit

a cga to vga converter
http://alvaamusement.com/_wsn/page4.html

if you are running mame why can't you just plug the pc monitor direct to your pc

[SirPeale]

Sounds like he has both a Mame cab and a Galaga.

Short version: you'll spend more on a scan converter than either fixing your monitor, or getting a new one.  Fix the old one.

And, as per this sub-forum rules, you have not posted the make and model of your monitor.

http://forum.arcadecontrols.com/index.php?topic=62016.0

[akcrash]

Sounds like he has both a Mame cab and a Galaga.

And, as per this sub-forum rules, you have not posted the make and model of your monitor.

Yes I do have the galaga cab and the MAME cab that I am building.

Sorry about the monitor info. I believe it is a WG K4600 monitor. Thats what the cap kit I ordered was for, and all the values matched and I did not have any leftover.

I think I am going to try and fix this monitor after seeing the prices of the converters. That and the only part I hate about monitors is working around the fragile tube, which I would have to do anyway if I tried to swap in a pc screen.

your monitor sounds like it has suffered from vertical frame collapse,some chassis will not power up with a fault in the frame circuit

a cga to vga converter
http://alvaamusement.com/_wsn/page4.html

This sounds correct, but it would actually be a horizontal collapse since the galaga cabs used a horizontal monitor rotated to vertical position. Do they still have the same 'protect' feature in the horizontal range too? I would think they would...
That converter sounds like it would work pretty slick, I might use that as an option if I cant fix this one.

Thanks for the advice so far...

[grantspain]

if you have a line down the centre of a vertically orientated tube then it is a vertical frame collapse

[SirPeale]

Assuming the images are on a horizontal monitor, which does yours resemble?

http://forum.arcadecontrols.com/index.php?topic=45137.msg835694#msg835694

[akcrash]

Assuming the images are on a horizontal monitor, which does yours resemble?

http://forum.arcadecontrols.com/index.php?topic=45137.msg835694#msg835694

Mine looks like the horizontal collapse, on the left. But my monitor is vertically orientated. So that would make it a vertical collapse then... right? This seems to be getting confusing, wish I had taken a pic before it died completely.

Crude representation of what it looked like:
_____
|   |   |
|   |   |
|   |   |
-------

The center vertical line was the collapsed image.

[SirPeale]

Like I said, assuming a horizontal monitor.

Okay, so you've got vertical collapse.  According to the Randy Fromm flowchart, check TR305 and TR306, and then TR301-TR307.  Check for bad solder joints (which this monitor is notorious for) and replace C310, C311 and C633.

If it's completely dead now, that's another different problem.

[akcrash]

Yeah, last time I messed with it it looked completely dead. But if it were going into that protection mode, wouldn't it look 'dead'? I will check those transistors regardless when I get home from work. I am stuck at work till the 22nd of this month, but I will look at it then. Where did you find this flow chart? I would like to do some reading up on these monitors, but last time I tried searching google I did not find much. Stupid work keeps getting in the way of my arcade work!

Thanks again for all the help.

[SirPeale]

I can't post it here (it's copyrighted and Randy has asked us not to).

[akcrash]

All right I got the monitor to power up again, I found a bad fuse on the monitor main board - F601 Replaced that and it came back up with the the vertical collapse. I also found X603 broken in half on the main board, got one at radio shack and will replace soon, according to the schematic it looks like it is part of the degauss circuit.

I also believe TR305 is bad, as when I measure from Base to Emitter and collector, I get .9 reading both B-C and B-E but when i reverse the leads B-E is .9 both ways. This seems hokey to me, so I have ordered some spares. TR306 checks as you would expect a normal transistor to check, so I think it is fine.

I will post back when the parts come in.

Thanks everyone for your help.

[akcrash]

Ok parts came in a few days ago. When i pulled the transistors out of the circuit they measured the same as the new ones; replaced them anyway. I also replaced diode X603. Put everything back together and the monitor powered right up! I suspect that the transistors were breaking down under load.

When it came up the colors were all out of adjustment. Managed to get them dialed in and the picture looks pretty good. The only other problem I am having seems to be bad connectors on the daughter boards. When the monitor firsts powers on there is a dark bar moving across the screen from right to left, it then fades out over the next few minutes. Then once the monitor is on for about 45 minutes to an hour it starts to lose vertical hold. I believe it is connector related cause if the boards get moved the monitor comes up with nothing but jagged lines.

Long story short does anyone know a part number for those connectors? Tried searching google for the number in the manual but came up with nothing. I am tempted to just make some jumpers and remote mount the boards to the side of the cabinet, but not sure if making those connections to long will cause issues.

Thanks for all the help!

[SirPeale]

Have you tried resoldering them?

[akcrash]

That was one of the first things I did. Most of the solder joints were cracked, but they are all freshly re-soldered now. The plastic connector housing on one of the boards looks burned almost. Either that or aged brown. But the socket connections don't look so good, and they fit loose.

[SirPeale]

You could probably tighten them up a bit by taking something thin (dental pick) and pushing the contacts so there is more tension.

[akcrash]

Ok, now I am really confused. Everything was working, played a long game, monitor looked perfect. Wanted to see if the credit switches worked, so I shut the game down, and flipped dip switches 1-3 off for 1 credit / 1 coin. I didn't touch or move any connector; turned game back on and the monitor displays the star field, but everything else looks like it is stretched into long jagged lines across the screen.

I have already reset all the socketed chips on the gameboards. This would seem to point away from the monitor interconnections. I have checked all solder joints for the connectors, they all look good or have been reflowed.

I bet if I let it sit for few minutes it will come back up like normal again - it's done this all along.

Sorry for all the questions, but I am way confused now...

On the bright side, my coin door works tho... Off to do more troubleshooting...

[akcrash]

So if the game sits for a few minutes it will power up and the monitor either comes up perfect or the picture looks good just with a wave of dark that goes across the screen from right to left, but this goes away after a minute or two. If I turn the game off and touch anything inside(like changing dip switches or changing from normal fire to fast fire; the game came with the factory rapid fire board.)  it comes up with the graphics skewed diagonally across the screen; looks like a sync issue. Turn it off let it sit for 3-5 minutes and it all comes up good again.

I could swallow that its a connector problem but you don't have to even touch a video connector to make it tweak out. Any further ideas would be great. Just want to say thanks again for all the help with getting the monitor working in the first place.

So no one knows a cross reference for the monitor daughter card connectors? I am going to try and find something that will work, if I find any thing I will post the part numbers...

[ncflagg]

...it comes up with the graphics skewed diagonally across the screen; looks like a sync issue. Turn it off let it sit for 3-5 minutes and it all comes up good again.

Could be that your power supply +5V needs adjusted. I've read that it should be set at 5.2V for Galaga.

http://www.arcadeshop.com/galaga/galaga.htm