Replacing B&W monitor

[YoGaBaR]

I have a space invaders cocktail and I was wondering if I replace the monitor can I use any monitor? Maybe upgrade to an LCD? Or do I need another B&W CRT monitor?

[SirPeale]

What's wrong with the current monitor?

[Jack Burton]

A lot of arcade monitors use the same tube as a television.  That means that if you can find a television with the same tube size you can replace the arcade monitor tube with the television tube.  This will remove any burn in or dimness in the picture.

This will not fix any problems with the chassis of the monitor.  To do that you will need to get out a multi-meter and check each capacitor on the board, or simply replace them all and see what happens.  Alternatively you can just buy a new chassis and install it.

I don't recommend an LCD monitor as a replacement.  It might be easier to work with, but would ruin the authenticity of the machine.  Putting aside any differences in image quality you are left with the simple fact that Space Invaders didn't have an LCD monitor.  And with a cabinet this old and this well emulated most of the joy of a restoration lies in authenticity and accuracy. 

So, with that in mind you need to do the following:

1.  Find out what type of monitor is in there.  Look at the back and look for a model number.  Also take a picture of the tube and chassis, including any numbers you can find.

2.  Find out what type of monitor Space Invaders came with.  It may have been swapped at some time the past.

3.  Find out what type of televisions used that same tube type, or even the exact same tube.

4.  Look around online and off for a replacement tube.

If you get very lucky you may be able to find a small black and white tv that you can use for parts and be able to perform a complete resurrection of this monitor back to exact specs. 

[YoGaBaR]

SirPeale:
It has alot of burn ins on it and I was looking into options for replacement.

Jack:
Is there a guide to look up tube numbers and a guide on swapping tubes?

Thanks for the replys

[Jack Burton]

Theses pages will help you out:

http://www.arcadetreasure.com/monitorinfo/Monitortubeswap.htm

http://www.rcilink.com/arcade/TubeSwap_steps.htm

But I recommend you do a lot of reading about how CRT's work, and the basics of what each component does.  

A word of warning:  This is a fairly advanced thing to do.  If you don't feel confident in your abilities as tech yet then I would avoid it.

I was maybe a little too hasty in my advice to do a tube swap.  The main reason why anyone does a tube swap is to save money or time.  If you are willing to pay $100 or so for a used monitor in good condition then that may be better.  

[YoGaBaR]

I will look into it!
Thanks for the help 

[Kevin Mullins]

It's most likely a Motorola monitor of sorts..... and granted a tube swap is possible it will have to be from a black/white donor which will greatly limit your options these days.

[YoGaBaR]

If I must... Will a color CRT replacement be fine? Will it still play in B&W?

[Rickn]

So as long as the game is raster and not X-Y, you should be able to use a color monitor. That is assuming that if the gane is CGA (15.75  Khz) your replacement monitor will accept the same.

Now the issue of Balck and white vs color. As the game is black and white you will only have 1 video signal (B&W) you will need to tie all 3 (RGB) signal input wires together and connect it to the games single video wire.

Good Luck

Rickm
Rick@Niemandisplays.com

[Kevin Mullins]

Now the issue of Balck and white vs color. As the game is black and white you will only have 1 video signal (B&W) you will need to tie all 3 (RGB) signal input wires together and connect it to the games single video wire.

So if the signals were tied together at the video input on the chassis would that essentially drive all three guns simultaneously ?
Would that not apply "color" of sorts (R+B+G) to the image or would the combination of colors become blacks and whites ?
What about neckboard pinouts, as a b/w tube typically has fewer pins doesn't it ?

Trying to visualize this functioning in my head.... never even thought of trying to use a color crt for a b/w game.

[DillonFoulds]

Think of a CRT color pixel, made of Red Green and Blue dots. White is made of R255, B255 and G255 or all on, and black is made of R0, B0, G0, or all off.


When you're tying these three signals together, you're essentially sending the same image on all 3 color guns. if you disconnect two color signals on a color monitor, you'll understand what I'm trying to explain.

Essentially what you'll end up with, is all 3 colors showing the same pictures, and you'll end up with the proper greys.

The downside to doing this would be if a color gun is off (bad convergence), you'll end up with colored ghosting. On a black and White monitor, you'd only have a "bent" image.


And about neckboard pinouts, I believe what Rickn meant was replace the entire bw monitor with an RGB, and tie the signals togehter right off the gameboard/going in to the monitor chassis.

I'm a newb to a lot of this, someone feel free to jump in if i'm off base here.

[Jack Burton]

I have a 13" Zenith black and white tv that is in good shape if that is a possible tube swap. 

Fascinating to know that it is as easy as sending the same signal to all three guns. 

Space invaders was a raster game, so this is looking promising.

My question is this:

If the convergence on the monitor is poor could you just connect one signal wire and have single color B/W? except in this case it would be G/W.

[YoGaBaR]

Great questions! Thanks for the replys!!!

This is some great info.

[Kevin Mullins]

Ah..... definitely great info on using a color crt as a replacement.
(I hate to misinform anyone)

Just one of them things I never really run through my head, but it all makes sense.
I only have one B/W game at the moment, but I'll have to try this out just for kicks sometime. 

[DillonFoulds]

If the convergence on the monitor is poor could you just connect one signal wire and have single color B/W? except in this case it would be G/W.

Yeah, that'd be correct, you should end up with G/W, the picture might be a bit dark, but i'm not sure on that. Also, i tihnk a 13" tube is probably going to be a bit small for a cocktail, but again, i'm noob here, so i'm 100% speculating.

[Jack Burton]

If the convergence on the monitor is poor could you just connect one signal wire and have single color B/W? except in this case it would be G/W.

Yeah, that'd be correct, you should end up with G/W, the picture might be a bit dark, but i'm not sure on that. Also, i tihnk a 13" tube is probably going to be a bit small for a cocktail, but again, i'm noob here, so i'm 100% speculating.

I'm gonna take a second to correct myself here.  The image wouldn't be G/W, it would be G/B.  The white coloring is being replaced by greenness.  A totally white screen would instead be a neon green.

I think Space invaders in G/B would probably look pretty cool.

[DillonFoulds]

Whoops, yeah that's what i meant. Black and Green. Still, i think that the end picture might end up a bit dimmer than you're expecting, or it might not...

Hard to tell until you try it out maybe?

[Jack Burton]

Well, I can maybe try this out.  I have an RGBHV monitor.  If I disconnect the R and B lines will that be the same thing as what we are discussing?

[DillonFoulds]

Do you mean to remove those 2 lines for a B/W game? If you're using a B/W gameboard, it will only have one video signal, just hook that up to the Green feed on the monitor.

If you're using a PC, you might need to tie all 3 color lines together and hook it up to the green input. Otherwise you'll probably have a pretty dim screen.

Again, just speculating here...

[YoGaBaR]

That would be kina cool if it were black and green or black and blue. Let us know how you hook it up and what the results are(pic).