need help with monitor installation

[redfivexw]

Hi,
tonight i am trying to put a monitor that came out of a super pac man machine (zenith 19") into an Atari Xevious machine.  I hooked up the RGB and sync, and am getting a picture, but it has constant wavy lines going up and down (looks like an old tv with the vertical or horizontal hold out of whack).  The monitor does not have hor. hold or vert. hold adjustments, it has Vertical Center, Horizontal Center, Horizontal Oscillator, Red Drive, Green Drive, Blue Drive, Green Cutoff, Blue Cutoff, and Red Cutoff.  Does anyone know which buttons to turn to get a clear picture, or perhaps i am doing something wrong.  I never actuall saw this monitor have a picture before, because the super pac boards were dead, but it looks like new.  Please help.

[MonitorGuru]

Zenith does not make commercial arcade monitors. They did make picture tubes however (or have others make them for them more appropriately).

Check for other markings on the chassis. Common ones out at that time were Electrohome G07, Wells-Gardner K46xx or K49xx series (e.g. 4616, ...) or Hantarex (a couple models)

Horizontal Oscillator would be Horizontal Frequency, aka Horizontal hold.

Since both SuperPac and Xevious are vertical oriented monitors, "tear" lines going up and down mean the horizontal is out of whack.  (Vertical hold would give an image you could make out but would just roll from side to side or flicker)

Adjust Horizontal Oscillator until it gives a good image. If you go to far in either direction, the monitor MAY shut off due to x-ray protection circuitry or other issues to protect the chassis from an out of range setting. If so, recenter the control and turn the power off and back on.


Without knowing the exact chassis brand and model thats about all I can help you with.

Also, be aware that there are two types of sync signals... positive and negative. Some monitors support both, others only negative. Most gameboards put out negative sync, while some put out positve, and you must connect the sync wire to a different jumper on the monitor for it to work. That may also be the problem, but I don't know without looking up a manual to know if Xevious uses positve or negative sync.

[redfivexw]

thank you for your help, i will adjust the hold tonight and let you know what happens.

[redfivexw]

i tried adjusting the horizontal oscillator, the picture only got worse, i put it back where it was and at least i could make it out.    I checked all over the monitor and all the marking on it, the tube and the electronics board were all marked zenith.  It said mfg 1982 Zenith, model number CD19MXRF06.  I believe it is original to the super pac machine.  the original monitor in the xevious was a wells-gardner 19K4604, which i know was not original as it had taped wires and a mfg date of 1980 (before xevious was made).  I am at a loss what to do next.

[redfivexw]

also, the original super pac wiring harness had a lot of extra wires going to the monitor, one harness had RGB and sync, next to that was another harness that had 4 more wires on it.  I have no idea what those wires did, i only re-connected the RGB and sync back up to my Xevious.

[MonitorGuru]

CD19MXRF06 is probably attached to the picture tube and not the electronics board, right?

I looked up and Xevious uses negative sync.

Extra wires from SuperPac may have been because they had separate ground wires for each RGB line as well.

You should only need 5 wires: RGB/Sync/Ground.  Make sure you have ground connected otherwise you may not get a stable picture.

Also be sure that if the monitor requires 2 inputs for sync, you run the single sync wire to both pins (just make a Y adaptor to send the same wire to both pins).

[redfivexw]

the numbers i listed are the model number, which are on a sticker which is on the board that has the electronics on it.  The tube has another number on it.  Let me tell you how the wiring went:  The wiring in the cabinet from the board had 5 wires, Red, Blue, Green, and then two other wires.  One wire is blue and the other was purple.  I assumed these were the sync wires.  I attached the wires to the 5 coming from the first monitor plug.  I first attached the RGB, then i attached the two remaining wires, one brown and one yellow to the sync wires.  The two wires on the monitor (brown and yellow) are connected together at the harness, i do not know where the ground is.  There is a black wire on the second harness, but it is not connected to anything.

[redfivexw]

ok,
i reconnected the wires, now i have coming from the board, RGB to RGB, then i have one wire from the board attached to the two sync wires.  That leaves me with what i had before on the screen and an extra wire.  I attached the extra wire to each of the wires on the extra harness on the monitor, one wire gave me a better picture, it was stable up and down but was rolling L-R, gave me something like this:  XEVIOUSXEVIOUSXEVIOUSXEVOIUS.  There is nothing marked Vertical hold on this monitor so what do i do?  Is there something else i am missing? 

[redfivexw]

ok, i think i figured out most of my problem.  that second wiring harness actually contained two sync wires.  the first one just had a ground on it with RGB.  I attached the two sync wires to the wire from the board, and connected the ground to what i believe to be the ground and i got a stable picture on the screen, however, the screen is out of focus and the green background is not there, all the other colors are bright but the green is almost non-existent.  I am going to bed now, and will mess with it tomorrow, but if anyone has any ideas how to get the green back and make the picture sharp, please advise.  thanks!

[MonitorGuru]

Out of focus screen:
- Adjust the FOCUS control on the back of the (black) flyback transformer (where the large red wire leading to the tube comes out of)

Lacking green:
(quick fix)
- Turn up the green DRIVE control and CUTOFF control.

Correct color balancing:
(long fix)
- Adjust the Red/Green/Blue DRIVE controls (on the board) to minimum.
- Adjust the Red/Green/Blue CUTOFF controls (presumably on the neckboard) to center.
- Turn up the SCREEN control on the flyback (next to FOCUS) so you see the image and keep going until you start seeing the retrace lines with an overall "fog" on the screen--especially in the black areas. Then back off until it's *almost* black again
- Now adjust each of the DRIVE controls so the level of color is the same in the black areas (e.g. if only blue is lit in the black area, bring up red and green slightly to match the same level to make it grey)
- Now turn down the SCREEN control to make black pure black again.
- Now adjust the CUTOFF controls to ensure that you don't have bleeding of colors to the edge of anything.


If STILL no green no matter how high you set the green drive controls/screen control and turn down red/blue, then you have a problem with the chassis or tube.. Either the green gun is shot (replace the tube) or the transistor (or associated components) is bad in the chassis, OR the output from the video board is bad not supplying green.  Test this by swapping the inputs (connect R to G and G to red and see if you see green now... if not, then your xevious board is fine.)

[redfivexw]

thank you for your advice, i truly appreciate it.  I will try it tonight.   If i cannot fix it, i think i will buy a new monitor! 

[Ken Layton]

Zenith did make one model of arcade monitor. It was included in a partial run of Super Pacman and Burgertime games. I've only seen ONE of these monitors in my entire career of fixing games. It was a long time ago but I remember that it (like many other Zenith products made after 1970) was a true piece of crap monitor. Schematics to this monitor are at atarijeff.com

[MonitorGuru]

I stand corrected by the TRUE Guru: Ken.  Thanks for the info Ken

At least he only saw one in his entire career, where I have seen none in my hobby