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Arctic Dweller
Joined: 31 Oct 2009
Posts: 13
Location: CANADA
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| Posted: Tue Dec 08, 2009 7:39 pm Post subject: SONY G70 BIAS Problem - Need Your Help, Please |
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Gentlemen:
My SONY G70 has a problem with the BIAS control on the Green tube.
The BIAS seems "stuck on maximum output". Regardless how I dial the BIAS Up or Down, there is no change in the brightness. However, the GAIN function works perfectly.
BIAS and GAIN functions on both Red & Blue tubes are O.K.
I swapped out the Neckboards between the Blue and the Green CRT tubes, and the problem was not with the Neckboard.
I then sent the Green tube to VDC in Bossier City, Louisiana, where Charlie installed a brand new Panasonic Green tube. I got the tube back and re-connected it to the G70.... SAME PROBLEM! BIAS still does not function.
I called Charlie today and he tested the BIAS on the old Green tube and it works fine (only had 935 hours on it, too!).
So, the problem isn't the new Green tube, and it is not the Neckboard, either. It must be what is feeding the Neckboard.
One of the other symptoms is that the Raster on the Green tube "glows" even when I blank out the Green tube.
The G70 has only 935 original hours on it and is in mint condition.
I am not a technician, and I am at a loss in where to turn to next to solve this problem.
Your knowledge and expert advice would be greatly appreciated!
God Bless, John.
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winduptoy
Joined: 25 Nov 2006
Posts: 187
Location: Lunenburg, Nova Scotia
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| Posted: Tue Dec 08, 2009 8:26 pm Post subject: |
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Just for fun go into service mode and push the bia & green buttons. Push bias again and you should get G2. adjust it downwards until it is looking fairly normal. push the bias button again and see if adjustments will work.
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Tue Dec 08, 2009 8:33 pm Post subject: |
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Good point, I didn't think about that.
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Arctic Dweller
Joined: 31 Oct 2009
Posts: 13
Location: CANADA
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| Posted: Tue Dec 08, 2009 10:23 pm Post subject: |
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Great suggestion, but I cannot access "G2" as you suggested.
The SONY G70 I have, has Firmware Version 1.10 installed.
I believe one can only access "G2" with the older Version 1.03?
Please keep those ideas coming!
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AFryia
Joined: 09 Mar 2006
Posts: 965
Location: S.E. Michigan VPH-G70Q
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| Posted: Wed Dec 09, 2009 11:46 pm Post subject: |
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What is your Brightness setting at? Try lowering that.
2nd if you accidentally swap the two heavy black wires to the "C" blocks (neck boards) the raster glows permanently, been there done that.
_________________
My Volt Blog
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