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Main => Monitor/Video Forum => Topic started by: Customcade on February 08, 2023, 03:13:46 am

Title: "Fixed" 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: Customcade on February 08, 2023, 03:13:46 am
Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later.

I can leave the game on and shut the monitor off separate for a few minutes turn it on and it's a nice crisp display again but few minutes later it slowly dims out to a blank screen.

Last time I did a cap kit was probably ten years ago but figured I would ask before I jump in a replace stuff that was perfectly fine type thing.
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: Ropi Jo on February 08, 2023, 03:14:54 pm
Slow fade to black is usually the heaters going out in the neck. I don't know your monitor. I'm an old school TV engineer. Check for dry joints on the tube neck conector and around the LOPTX.
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: Customcade on February 08, 2023, 07:18:32 pm
Cool thanks for the reply and will check it out.

Been over a decade since I last did the cap kit and don't remember if I can or cannot pull the neck board without discharging it first.
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: Customcade on February 10, 2023, 08:59:20 pm
Are these caps leaking, looks like toothpaste and not hot glue.
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: Customcade on February 10, 2023, 09:03:48 pm
Couple other spots
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: Customcade on February 10, 2023, 09:18:25 pm
Final example
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: grantspain on February 11, 2023, 03:14:07 am
you would need to monitor the hv and b+ to prove whats going on

that is just factory glue around those caps

the sort of fault you describe is more likely bad solder joint and i would look in particular around crt socket and rgb input but in general the entire chassis should be investigated

i don't have any experience with this size tube but from previous readings I have seen known issues with 39" tubes and failure similar to this
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: buttersoft on February 11, 2023, 06:04:03 am
i had a bad solder joint like than on the neckboard connection for the G2 that made the screen slowly go dim, but it was like a thermostat, and kept fading in and out about once a minute.
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: Customcade on February 11, 2023, 05:52:08 pm
i had a bad solder joint like than on the neckboard connection for the G2 that made the screen slowly go dim, but it was like a thermostat, and kept fading in and out about once a minute.

That's what this is doing, it's acting like a heater issue.

I checked the back side of the neck board and looks good but will just have to pull the main PCB and look them over again.

I was just hoping to fix it without having to pull it out again.
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: grantspain on February 11, 2023, 06:27:20 pm
next time it happens increase the screen volts on the flyback to see if you obtain a raster, that will eliminate a load of issues
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: Customcade on February 11, 2023, 08:09:22 pm
Will definitely try it, I have not played with any setting's on anything or touched any of the pots for it yet.

It's a nice crisp clear still display when it's working it just fades out after a few minutes after it seems to heat up some.
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: Ropi Jo on February 12, 2023, 03:06:20 pm
If you turn the lights down in the room you'll clearly see the tube heaters. Watch for the heater going out when the issue occurs.
Title: Re: Wells 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: Customcade on February 17, 2023, 03:10:21 am
It ended up being bad solder joints from the manufacture.

Mine all still looked solid shiny and purdy from the cap work I did a decade ago.

I seen at least three points that didn't look good at all so I got those three and then there was about ten more that were questionable if they had a hairline crack so I just hit them all with some heat and added a little fresh solder since I already had it out might as well type thing.

Put it back in and I let it run for 2-3 and was perfect but now the screen was actually too bright where the black was more grey and the white color was too rich so I just barely touched the screen pot on the flyback and turned it down a hair and boom it looks like a brand new screen again.

Thanks for all the help and suggestions, glad it was a free fix and one I could tackle with all of your help again.
Title: Re: "Fixed" 39k7600 issue, Screen is beautiful but fades dims out 10 minutes later
Post by: buttersoft on February 17, 2023, 07:58:58 pm
glad it was a simple fix!