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Project Weekend & The Man from O.N.C.A.L.L.

creepingnet

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Joined
Feb 25, 2005
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Reno, NV
First weekend On-Call, in between calls for (mostly) Basic I.T. stuff, I've been working up a storm in the lab........

TANDY 1000A - Upgraded the XUB on the XT-IDE REV1 controller - finally, it's about time, the last time I ever flashed that thing was 2009, and it totally pays that the boot time is now HALF of what it once was and programs load faster as a result. Currently using the Beta v3 firmware without issue.

1989 Mitsubishi CS-2720R - I switched out the gaming TV's while I was at it, and finished up the Mitsubishi CS-2720R TV. It's a much nicer set than the Magnavox in that it has not one but two Composite inputs, one S-Video, Composite out (that pushes ANY video signal the TV recieves out of it). I bought a tube of Dielectric Grease (which I also needed to service my Wife's car this weekend - new battery) so I could make sure the zapping noises were not coming from the anode cap having a loose connection (as I cleaned and removed most of the Dielectric in the process). It's been sitting in the closet for about a year at this point, doing nothing.....this was the biggest marathon of work of the weekend...

- Dielectric grease Anode Cap and connections
- Re-Adjusted Screen and Focus, found that the Screen voltage is more than high enough for my needs, so I backed it off, so it buzzes less when showing bright/white screens
- Manually Degaussed the tube using electric guitar speakers.....it took 2 days and a lot of twirling magnets while watching YouTube videos but I got it good enough for now until I feel like bothering with ordering a Degaussing wand or ring.

As it stands now, the Mitsubishi only buzzes when the screen is white (or very close to it - like Beige or neon colors at this point, and it seems 2 days of off/on "burn in" has been good for the circuitry in general as it's buzzing less and less on brighter screens as time goes on and seems to be getting more stable. Other than that, ultra-sharp, still quite bright (despite dialing the Screen voltage down at least 200 volts), and it plays nice with the Roku, a little nicer actually since the aspect ratio is less square and more WEGA level (the screen's a hair wider). Turning off all the lights and staring down the back reveals a dark orange CRT neck (Electron Guns or heaters I guess), and ZERO arcing or sparking. My theory is when the voltage goes up it's making that metal thing in the middle of the flyback vibrate....and that's alright by me since I mostly use the TV for games and most of my games are pretty dark. Dragon Warrior IV does not even make it buzz.
 

creepingnet

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Joined
Feb 25, 2005
Messages
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Location
Reno, NV
Gary C - Dielectric grease is used on Anode Caps on CRTs to help isolate the high voltages beneath and prevent arcing. I'm using that because that's what every CRT forum/website/etc. I can find lists as the proper stuff to use. If you remove Dielectric grease from the back of the tube, the small, sometimes even microscopic imperfections in the anode cap will allow stray 24KV to possibly arc from the internal to external DAG. IPA was used prior to putting on the new grease to fix the issue. Seems to have helped for the most part, I've been using the Set since that weekend without issue, recorded several YouTube videos with it as well, including some gaming.
 

Gary C

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May 26, 2018
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Location
Lancashire, UK
Certainly when I was trained in CRT maintenance at work, nothing had any grease on it. In fact, cleaning coal dust off things was the issue. Maybe being used in coal fired power stations meant grease was a big no no because any grease would attract coal dust and that stuff is conductive and can play hell with HV. Our mantra was just make it clean and it wont arc. Though I cant see how even a 40kV colour set can have arcing on a clean glass and rubber anode even with imperfections as they are just not conductive. It would take moisture to get into the imperfections. Maybe in certain climates where there is a lot of condensing in a set ?

But hey ho. If its sold then it must be for a reason.
 
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