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Recapping the screen based on the advice on the other thread. To be honest. The screen is flickering more and more and happened 2 times to lose color and then coming back (neckbord probably) on it’s owm.
I had this fault. The two likely issues are:

1) The soldering for the color drive transistors on the neck board. The transistors run really hot. The solder pads will most likely have come off. Reflow and apply jumper wires where necessary.
2) The pots on the neckboard for color cutoff and drive can get crusty. Fix it with spraying contact cleaner in them and then giving the pots some good full turns or swapping the pots for new ones.
 
Will look into it more, not not have time to take it apart today as I thought Inwould.

Did a very quick check, the solder seem ok from underneath at first glance (will try to take a better picture)
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But you can see from the top that the PCB is a bit burned/brown from the middle transistor
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For the Chassis, while it “looks good”, I’m not sure if the white thing is coming from the caps or some other thing, that’s why I still wanted to recap

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I also noticed a few cables being flismsy, like this whit one on one of the connector on the chassis:

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And this one that goes to the remote board:
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If you slightly rock the transistors you can see if the pads are coming off. Top side has definitely gone brown from the heat.

The white thing is just glue.

The wiring you definitely want to fix, although in their current state neither of which should be causing the issues you describe. The white wire on the connector is for sync. You would have a rolling image if that wasn't connected. The one for the remote is so well twist tied that it can't not make a connection.
 
Looks like your monitor is a good candidate for a Simple Green wash as well. Getting rid of the grime on the parts helps with heat dissapation. Less heat, longer life. The Sun is out in California today too. So take advantage of it.
 
I'm still coming to term about discharging the CRT, seeing that Simple Green and water from the hose getting close to the hole for the anode plug is freaking the hell out of me :P I don't have a garden as I live in an apartment complex so not sure I will do it,,, Maybe just on the chassis and neck board.
Also rain is supposed to come back tomorrow here ;)
 
Wash the chassis now. Dry it under a fan for a day. Do the tube in the Spring.

That wire that wraps around your tubes ears is litterally called the grounding strap. So you can safely tie to that to discharge your tube. Just remember that the tube can build up more charge a few mins later so you should discharge it again in 15 mins.
 
This is so great, I know i probably say this everywhere i see these kinds of posts. But damn I love a good restoration. That control panel is great too really digging it.

I recently rebuilt my Nanao MS9 chassis. It always makes me nervous playing around that high voltage circuitry. Just do your best to ground the thing and carefully get that chassis out and take a look around and make your repairs. If you have not recapped it yet, go ahead and do that since the chassis is already out of the cab.

My issue with my Chassis was that the screen would constantly change its color temp/brightness if it got bumped. So while i had the chassis out to do the recap I noticed a lot of the adjustment trim pots and the remote board connector had bad solder joints. After I fixed all of that and cleaned the years of dust off, she was working a treat.

Best of luck and keep us posted.

And follow acblunden2's advice, that is basically all you need to do. ^^
 
The screen keeps having more and more issues: the « hourglass » comes and go more often, and it keeps dimming brightening more and more as well. The hourglass can be related to the little board on the chassis that controls this, I think, but I’m afraid about the brightness dimming, that it could be the tube :( hopefully it will be as benign as you Geekman :)

Anyway still not do anything to it yet, as I am waiting for my replacement transistor to arrive. I will finally try the discharge tomorrow now and remove the chassis and neckboard for cleaning, since I will have my NNC this weekend to play on instead :)
 
As said before a cap kit will do wonders on a W-G.
 
Yup yup! Not dismissing any of your advice: got my cap kit ready, waiting on the transistors for the neck board so I don't have to re-tinker if I need to later, tonight I discharge and remove clean the chassis and then I'll have fun with all the soldering over the week :) Just wanted to give an update on progress :D Thanks!
 
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The screen keeps having more and more issues: the « hourglass » comes and go more often, and it keeps dimming brightening more and more as well. The hourglass can be related to the little board on the chassis that controls this, I think, but I’m afraid about the brightness dimming, that it could be the tube :( hopefully it will be as benign as you Geekman :)

Anyway still not do anything to it yet, as I am waiting for my replacement transistor to arrive. I will finally try the discharge tomorrow now and remove the chassis and neckboard for cleaning, since I will have my NNC this weekend to play on instead :)
Yes discharge, recap and clean up / reflow solder on all the adjustment pots and plugs on the board and it very well may solve your issue. Best of luck and keep us posted
 
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No pop, no arc. Looks like it does discharge itself :) Next steps: recap, reflow, repin, redo!
 
Good to know you're still alive. But never assume there is no charge in a tube. Charge can easily build back up. Remember when you go to put that chassis back on, discharge the tube again. Biggest shock of my life came from touching the anode cap of a tube I had discharged 2 hours prior when going back in to reinstall a chassis.

Also dimming issues you mention sound to be at least a voltage regulator replacement job, at worst, a new flyback. But start with new caps. Also, go one at a time with a K7400. Variants of that chassis has caps in spots where some other variants don't. The cap kit you bought won't help you much if you make a mistake either. Don't put a cap where one wasn't previously. Make sure you mark the chassis as you remove caps as unpopulated cap locations near your removed cap can easily be mixed up. You'll see what I mean as you go along with this chassis.

Good luck. By far, the K7400 chassis is the worst chassis I have ever had to work on.
 
Update on the chassis:

Turns out the flyback has a hairline crack which is probably the culprit for those impromptu brightness changes.

Hopefully everything will be fixed by the end of next week, and then maybe trying to tackle the purity issue (discoloration on the lower left angle) that the degauss with a coil could not fix.

If not, trying to find a tube compatible with this chassis will be fun :(
FCA768B2-3C27-4D9C-B7C0-E53B4A575C4D.jpeg
 
Good thing about the flyback on the K7400 is that is in an open air spot on the chassis. On a K7000, it is nestled under the heat sink making it maddening to replace sometimes. Stupid pins sometimes never want to align.

To do purity tests/calibrations, you'll need a PCB that can output RGB color screens. 90's Midway boards are good for this. Also, the CraftyMech Test Pattern Generator is good for this as well.
 
Since I have an arpicade, I wonder if I could use this. Like a 240p CRT Test (maybe loading the ps1 iso as it reads PS games). Or maybe a CPS2 since I don’t have any original midway boards.
 
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