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Author Topic: Tube screen becoming blurry after minutes on.  (Read 1404 times)

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Dacasks

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Tube screen becoming blurry after minutes on.
« on: April 29, 2017, 08:41:11 am »
What it could be? Caps? Anyway to solve it?  It's a JVC broadcast monitor. My PVM blew and I can't find any technician to repair it :/

grantspain

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Re: Tube screen becoming blurry after minutes on.
« Reply #1 on: April 29, 2017, 10:06:34 am »
do you mean focus is drifting?
if so then either flyback focus pot just needs a tweek  or is faulty,bad connection in crt socket or bad tube

Dacasks

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Re: Tube screen becoming blurry after minutes on.
« Reply #2 on: April 30, 2017, 01:44:52 pm »
do you mean focus is drifting?
if so then either flyback focus pot just needs a tweek  or is faulty,bad connection in crt socket or bad tube

Hi, thanks for answering!

I wouldn't say the focus is drifting... more like the image losing it's sharpness.

buttersoft

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Re: Tube screen becoming blurry after minutes on.
« Reply #3 on: April 30, 2017, 08:14:18 pm »
This happens as flybacks age, sometimes. With arcade flybacks, anyway. Cracks in the casing or insulation breakdown mean that as things warm up the focus swims a bit. In some cases the image will be stable, and always in the same place - so you leave the cabinet on for 5-10mins and adjust the focus for that point. Other times the flyback will settle on a different point each time, and there's nothing you can do but adjust the focus every time you turn the cab on, but after it warms up - assuming this is the problem. It sounds like it, but this a broadcast set so I can't say for sure.

Some flybacks become a fire hazard as this gets worse, be aware.