Green arcade monitor problem

[maximumg]

hi all. I have a problem with my arcade monitor and all the colors show more greenish than normal. In fact it's like having a green mask. When the Jamma harness is disconnected the monitor is green.

The tube is goldstar but I don't know the monitor type. Please attached pics and hopefully you can tell me the monitor model

Thanks

[grantspain]

hantarex mtc9000

could be just a dirty green cut off pot(3 through holes in neck card for the cut offs)
could be a leaky drive transistor in green colour circuit

[maximumg]

Thanks

I'm new to this so I'm not sure what you mean with the cut off pot. What is it, where is it?

Thanks again

[baritonomarchetto]

The green drive transistor is one of those 3 mounted on the neckboard.
There's a third option: green cathode shorted, but replace the transistor first to see if it fixes

[maximumg]

The thing is that everything was ok. I moved the cab to another room and this happened. Maybe it's a lose contact? Maybe something moved?  I checked but all contacts look fine. Any ideas?

[grantspain]

if a gun is short then the colour will turn full on and you would have flyback lines as well
can you post a photo of a screen shot

[maximumg]

Here are some photos

[grantspain]

the green gun is full on,the only way to prove this is to desolder the pin to the green gun on the crt socket
if you send me a good photo of the neck card i will mark the pin to desolder

[grantspain]

actually its marked KG in the first photo

btw have you turned the contrast control anti clockwise yet?

[maximumg]

actually i'm a bit sceptical about starting tweaking everything as everything was ok before moving it to another room.

now i hear that i have to disolder stuff, replace transistors, dirty pots...... can all these be caused by just moving the cab?  are these monitors so fragile?

BTW when i removed the neck card to see if i had a lose contact the thing marked with a rectangle (plastic rings?) on the pic fell off.  What is that and what is it used for? Also there was a piece of tape beneath that that peeled off

[grantspain]

they are the purity/convergence rings-butt them up to the deflection yoke

if it was ok before moving then you have a bad solder joint somewhere

[maximumg]

Could the rings be affecting the green coloring?

[grantspain]

Could the rings be affecting the green coloring?

its unlikely but tbh in 30 years of working on arcade machines i have never bothered to see what happens if you move the convergence rings all way to the base of the neck

move the rings back to their correct position and see what happens

[behrmr]

I don't own this monitor but I can tell you that just moving a game can make stuff like this happen. As mentioned get your soldering iron out and start by reflowing the joints on the neck board and then work your way through the chassis and touch up anything that looks iffy.  Look in the manual for the green color transistors and possibly pull green and swap with another colors translator. I Just got done working on a g07 same problem and it had a bad green transistor. Also I don't think this is an issue with the yoke moving. I think it would have to move a significant amount to make this happen. My guess would be you'd see minor color distortion in the edges or center if it was just bumped a little.  You could also look for a collector in your area that has a rejuvenator to rule out a bad tube or shorted gun.


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[baritonomarchetto]

To rule out the shorted gun it is sufficient to desolder the green output transistor and look: if the green is still there you have a green cathode shorted

[maximumg]

Ok I made some progress I think. I moved the rings but nothing happened so I fixed them on the upper end.

I also checked all the solders on the neck board and I don't have any loose ones. Now when I removed the neck board I blew some air on the neck board connector and on the tube connector and when I put them back together the colors were ok for about a minute but then they went back as before

[obcd]

People are trying to help and are just summing up known faults that cause a tube to become all green. Obvious, you won't have all of those issues. You will have only one and maybe even a different one.
So, the first thing people tell you to check are dodgy solderings. Since the fault started after you moved the cab, a cracked soldering can start to give bad contact due to vibrations or shocks.
The second thing they tell you is to check the color drive transistors on the neckboard. Hanty has a reputation for those going bad. If you remove the green drive transistor, the tube shouldn't show any green anymore.
This brings us to the third thing that might be wrong. A short between 2 electrodes inside the tube. If you remove the green drive transistor (or disconnect it's output from the tube) ((There is usually a resistor between the drive transistor output and the pin on the tube connector))the tube shouldn't show any green anymore.
If that's the case, you can remove one of the other drive transistors and place that on the position of the green one. If the green becomes normal after that, you know you have a bad drive transistor.
I have seen such transistors that measure perfect when they are removed from the neckboard, but never the less where bad.
A fourth thing that can happen is a bad contact in one of the potmeters on the neckboard that are used for the color adjustment.
Usually, if you just move them a small mm clockwise and counter clockwise, you will see the fault appear and dissapear again.
It's possible that a short in the tube only starts when the tube has heated up. Sometimes, such a short can be removed by discharging a capacitor between those electrodes, but it's not an exact science and it can permanently damage the tube.