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MS2930 Chassis + MS2931 Tube - Yellow Tint on Screen

klee123

klee123

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Hi all


So I recently changed the tube and chassis and managed to get it working which is great.

The only issue is that the picture shows a yellow tint and it seems that the Blue color doesn't display properly at all.

I've read on other threads here that this is possibly due to the neckboard connected to the tube? So would this be a Chassis or a tube issue in this case?

Any info/assistance would be much appreciated. Thanks
 
Yellow does mean that your blue is not present. Does turning up the blue Drive and Cutoff pots cause any change in the display? Also check the Blue signal wire from the JAMMA harness to the chassis PCB.
 
ShootTheCore said:
Yellow does mean that your blue is not present. Does turning up the blue Drive and Cutoff pots cause any change in the display? Also check the Blue signal wire from the JAMMA harness to the chassis PCB.
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I've tested the blue cut off pot and it changed nothing.

With regards to Jamma signal, the previous chassis and tube worked had no issues, so I'm not sure if it's the signal wire issue.
 
So you have no blue at all? Double check with a color bar screen.
 
Speaking of which, does anyone know if there is a a schematic of the neckbiard of which transitor corresponds to which rgb color?

All I see are mainly of the main chassis of the list of capacitors.
 
Oh so the neckboards are identical between the 30 and 31? That's good to know too.
 
30X is red, 31X is green and 32X is blue. Start by swapping the transistors. If nothing changes, those are fine. Start checking the diodes next.

Another thing you should check is the wiring between the chassis and the remote. I don't know if you get no color if there's no connection to the gain pot, but it's easily checked.

Have you ruled out the cabinet wiring?

I spent an hour trying to find an issue in a monitor with a missing color some time back. Ultimately, it was a bad connection on the jamma connector. I felt like a dunce.
 
nem said:
30X is red, 31X is green and 32X is blue. Start by swapping the transistors. If nothing changes, those are fine. Start checking the diodes next.

Another thing you should check is the wiring between the chassis and the remote. I don't know if you get no color if there's no connection to the gain pot, but it's easily checked.

Have you ruled out the cabinet wiring?

I spent an hour trying to find an issue in a monitor with a missing color some time back. Ultimately, it was a bad connection on the jamma connector. I felt like a dunce.
Click to expand...
I'm quite certain that it's not the Jamma wiring since it was only 2 weeks ago I was still playing the blast with another Monitor/Chassis set and that had no color issues.

Really appreciate the info though, this friday once I get some desoldering wick, I'll switch those transistors around.

Also with regards to Diodes, do you mean the Zener Diodes?, on my neckboard, I see 3 of them at ZD301, ZD311, ZD321.
 
There are three regular diodes and one zener per circuit IIRC. Check them all. If you have a diode that's gone, check the resistors too, as those can go in tandem.
 
klee123 said:
I'm quite certain that it's not the Jamma wiring since it was only 2 weeks ago I was still playing the blast with another Monitor/Chassis set and that had no color issues.
Click to expand...
This is logical, and yet, loose wires happen. You're probably right, and that's not it, but I would not assume because it worked before that it works now. You did a swap, something could have pulled loose. Just keep that in mind. I've certainly had things "just stop working" and found a loose connection before.

I had a MS9 with no blue once. In my particular case it was a cold solder joint on the neckboard. Quick reflow and my blue was back.
 
nem said:
There are three regular diodes and one zener per circuit IIRC. Check them all. If you have a diode that's gone, check the resistors too, as those can go in tandem.
Click to expand...
Thanks, will have a look tonight.

Aurich said:
This is logical, and yet, loose wires happen. You're probably right, and that's not it, but I would not assume because it worked before that it works now. You did a swap, something could have pulled loose. Just keep that in mind. I've certainly had things "just stop working" and found a loose connection before.

I had a MS9 with no blue once. In my particular case it was a cold solder joint on the neckboard. Quick reflow and my blue was back.
Click to expand...

That is fair, never hurts to check in the end and will do a full check later this week.
 
Reflowing can be different processes.

Usually, in this hobby it's simply reflowing the solder point on a joint by adding more solder and refreshing the old solder to create a new connection/joint.

There are reflow ovens for certain applications, for the reflowing of solder on an entire board, but that obviously takes some science and preperation as you can imagine :)
 
djsheep said:
Reflowing can be different processes.

Usually, in this hobby it's simply reflowing the solder point on a joint by adding more solder and refreshing the old solder to create a new connection/joint.

There are reflow ovens for certain applications, for the reflowing of solder on an entire board, but that obviously takes some science and preperation as you can imagine :)
Click to expand...
Yeah, saw some vids where people are putting their PCBs in a specialized re flow over and I went ?(

Anyways, gave Jomac a call about this issue a few days ago and he suggested to me to just remove all the Zener diodes on the neckboard. Will give it a go tomorrow.
 
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Forgot to mention, with the neckboard from the broken chassis, I tried to remove one of the transistors, but failed miserably. I used the soldering wick to remove the solder, but because I only heat one connector at a time, I'd imagine any residual soldier on those connectors cool down really quick and remains stuck.

This is not fun to test lol
 
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