Mitsubishi VS-50803 CRT HiV Penetration


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Mitsubishi VS-50803 CRT HiV Penetration

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techa
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Dec 7, 2004, 7:13 AM

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Mitsubishi VS-50803 CRT HiV Penetration	Can't Post

Model: Mitsubishi VS-50803 VZ6 Chassis 50" HDTV-ready Rear-screen Projection
similar models: VS-50800 and VS-60803

Original symptom: Power on TV, hear hi-voltage crackle up, click like a clock then hi-voltage shutdown.

Problem: Traced to what looked like a gassy or no-vacuum RED CRT (P16LNM07RJA Tube). When took off the red anode lead from HV-BLOCK, set came on (blue and green) and stayed on. No evidence of coolant leakage.

Action: Sent red tube to Video Display Corp/Novatron for possible rebuild and if not rebuildable, new replacement. Told by Charlie at Novatron that my red CRT had a "High Voltage Penetration" under the yoke. He explained that high voltage somehow was at the yoke and was attracted to the forward-most electrode of the inside electron gun assembly. That attraction caused an arcing that went from the yoke, thru the glass to the electrode, burning a pinhole into the glass, causing it to lose vacuum. That red CRT is now useless. He said that he (as a CRT expert) has seen this happen in a lot of CRT's sent in for work but did not know of a 'fix' for this phenomena. He did say that he thought Mitsubishi was aware of this problem and had a fix but he didn't have access to that fix. He suggested that a Mitsubishi service center might know. The only problem is, nobody can call Mitsubishi except an authorized service center for technical help so I'm out in the cold on this one. My fear is, when I receive the new replacement red CRT, that the same thing happens all over again. If there is a fix for this, I would REALLY like to know about it or at least have some ideas on how to prevent it. My idea is possibly use "Corona Dope" on the CRT neck under the yoke as an insulator.

Here's where you guys come in... If any of you have access to Mitsubishi service, like an authorized SS or corporate, could you find out if there's a 'fix' for this or get some ideas?

In advance, thanks!

Regards,
Joe Jacobs
Technology Associates
Southern NJ

(This post was edited by techa on Dec 13, 2004, 8:28 AM)

minehunter
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Dec 8, 2004, 12:14 AM

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Re: [techa] Mitsubishi VS-50803 CRT HiV Penetration [In reply to]	Can't Post

I worked for an authorized Mitsubishi repair for awhile and you'll also need to replace the yoke. it's usually the yoke that goes bad and causes teh crt problem. I don't know why, but it does.

techa
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Dec 10, 2004, 3:39 AM

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Re: [minehunter] Mitsubishi VS-50803 CRT HiV Penetration [In reply to]	Can't Post

Minehunter, thank you for taking the time to respond. As a result of the information you supplied, I went ahead and ordered a replacement yoke from Mitsubishi. I'm still awaiting return of the crt as well as delivery of the replacement yoke.

Update: 12-Dec-2004. On Friday (12/10), the CRT came in from Novatron, the YOKE came in from Mits and the HV-BLOCK came in. I installed all items and with a little help from Charlie at Novatron, everything's working beautifully. No arcing, no problems.

Thanks again.

(This post was edited by techa on Dec 13, 2004, 8:21 AM)

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