Weak Green in 20EZ

[texasmame]

Got an EZ where green is weak. This is a vs. system if that matters.


Complete cap done, reflowed the transistors on the neckboard, even swapping a known good green transisitor from DK. Jr - no change. Even adjusted the color pots on the game PCB - still can't get the green to look good. It's there but it's just. . . blah. Green pot adjusting doesn't seem to do quite as much as the red and blue pots.

Results same with two different game boards. Connector's green pin area seems fine.

Don't have access to a tube rejuvinator. Hoping it's not the green gun going.

Suggestions?

EDIT: Added pics of what I have vs. screenshot of proper colors. In my pic, all color pots, on monitor and PCB, are set to their physical middle. NOTE: If I crank the green all the way, I do get the background checkerboard but it looks like crap.

 

[Dokert]

Verify the B+ is at 108vdc, then adjust your brightness and see what you get.

Keep in mind that there are 3 brightness controls.
1. Brightness next to the four other pots
2. sub-brightness uppr right hand side of the chassis
3. master brightness on the flyback

Consider them as:
1. fine adjustment
2. medium adjustment
3. coarse adjustment

 

[texasmame]

Verify the B+ is at 108vdc, then adjust your brightness and see what you get.

Keep in mind that there are 3 brightness controls.
1. Brightness next to the four other pots
2. sub-brightness uppr right hand side of the chassis
3. master brightness on the flyback

Consider them as:
1. fine adjustment
2. medium adjustment
3. coarse adjustment

The B+ is 108.

Should have stated that I've messed with all the brightnesses controls already - my bad. Still, nothing makes it look "right."

 

[texasmame]

One other note - I was unable to replace the NP caps (C162, C411) as no NP options were in stock. It looks like C162 is in the SYNC circuit and C411 MAY be part of the green circuit - can anyone confirm what these two caps are part of and if they may be having an impact here if they are bad?

They physically looked fine and were reflowed during the cap kit install. . .

 

[gregatron]

You may need to check the green gun with a rejuvinator and see what the emmision reading is. I have seen this before mostly on newer type tubes, not so much on a Sanyo tube but it is still possible. Did you check to see if the green pots were good and not broken or bad?

 

[texasmame]

You may need to check the green gun with a rejuvinator and see what the emmision reading is. I have seen this before mostly on newer type tubes, not so much on a Sanyo tube but it is still possible. Did you check to see if the green pots were good and not broken or bad?

I get something from the green pots, so they are at least semi-functional and not completely busted. I've no rejuvinator handy.

 

[Dokert]

I get something from the green pots, so they are at least semi-functional and not completely busted. I've no rejuvinator handy.

There are many around you

 

[texasmame]

There are many around you

Okay, I'll bite. Where?

 

[gregatron]

Okay, I'll bite. Where?

I'm sure what Dave is referring to is other members that are local to you. Also, many TV repair shops still have rejuvers around and will usually only charge $5 to $10 bucks to zap it or check it. (If they still remember how to use them). That tube should take a CR23 adapter.

 

[texasmame]

I'm sure what Dave is referring to is other members that are local to you. Also, many TV repair shops still have rejuvers around and will usually only charge $5 to $10 bucks to zap it or check it. (If they still remember how to use them). That tube should take a CR23 adapter.

Thought so but was hoping he was referring to the little known "just hook an exposed wire 110v up to the neck pins" trick.

I did call a T.V. repair shop down the road and it was $50 just to look at it. Ugh. Perhaps if I call them again with the CR23 adapter info, they'll have one and zap it for $10, which would be a perfect way to go here. Closed tonight, tho.

I'm toying with swapping the tube I have from the DK just to get to the bottom of if it is the tube or chassis. The chassis are different - on is wired for the vs. system, one for the DK Jr. dedicated setup - so a straight chassis swap is out.

 

[Slackmoe]

You might try reflowing solder on the green pots on the neckboard. If that doesnt work its definately the tube needing to be zapped like Greg said.

Andrew

 

[gregatron]

I'm toying with swapping the tube I have from the DK just to get to the bottom of if it is the tube or chassis. The chassis are different - one is wired for the vs. system, one for the DK Jr. dedicated setup - so a straight chassis swap is out.

There is no difference in output between a VS board and a DK series board. All classic Nintendo boards including VS and I believe even playchoice put out inverted video so the chassis should be swapable.

 

[texasmame]

There is no difference in output between a VS board and a DK series board. All classic Nintendo boards including VS and I believe even playchoice put out inverted video so the chassis should be swapable.

Oh, hang on. Yeah - duh. I was thinking a "monitor" swap - can't do that as they are wired differently but I think the chassis swap would work. It's all getting jumbled in my mind - thanks for the clairity. Will try soon and report back.

 

[texasmame]

You might try reflowing solder on the green pots on the neckboard. If that doesnt work its definately the tube needing to be zapped like Greg said.

Andrew

Reflowed EVERYTHING on the neckboard - shotgunning didn't work.

 

[Dokert]

ask your local klov brethren for some rejuv help

 

[texasmame]

Swapped out the chassis with DK Jr. and now both look fine. ???

Maybe something was shorted?

EDIT: Strike that.

I can get the colors on Golf to look okay but Dr. Mario is not correct.

Guessing it's the Mario PCB at this point. :/

 

[Frax]

I have this game now. I'm pretty much a noob, but when it comes to monitors I know about nothing....just what I'm learning from this so far. So anyone here in the DFW area have a rejuv they can zap the green cathode with? I can transport the monitor or you're welcome to come over if we can set something up. Figured I'd ask here before I start calling tv repair shops!