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hal
Joined: 28 Nov 2012
Posts: 100
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| Posted: Fri Aug 29, 2014 11:27 pm Post subject: Capacitor whine on G90 or ?? |
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My son mentioned that half way thru the last movie he started hearing a whine. The source is toward the front of the lens/centerline under the green lens. It should like nails scratching a chalk board. I pulled off all the covers and don't see any arching with the CRT HV wires. It really sounds like in the PA board.
I haven't heard of any arch snaps, the picture is perfect on all tubes..
Any thoughts??
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tschaeikaei
Joined: 08 Apr 2013
Posts: 490
Location: Germany/Saarland
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| Posted: Sat Aug 30, 2014 2:03 am Post subject: |
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Are there coils /transformers on that PA board? Sorry, i can't help much, never had a Sony.
Regards, Julian
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Marquee 9500U edgeblend P43 | NEC 9PG
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hal
Joined: 28 Nov 2012
Posts: 100
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| Posted: Sat Aug 30, 2014 2:15 am Post subject: |
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yes, four of them with 4 250V820uf caps..
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Sat Aug 30, 2014 2:40 am Post subject: |
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Are they glued to the board and the glue has cracks?
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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hal
Joined: 28 Nov 2012
Posts: 100
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| Posted: Sat Aug 30, 2014 3:41 am Post subject: |
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Not glued.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Sat Aug 30, 2014 4:41 am Post subject: |
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Pull them out and put the tester on them then 
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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hal
Joined: 28 Nov 2012
Posts: 100
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| Posted: Sat Aug 30, 2014 6:59 pm Post subject: |
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Replaced the PA board this morning (from my parts machine>failed YA board).
The noise is still there. It sounds more like grease slowly burning on a hot stove.
Any thoughts.. The HV coils are located up front I believe?
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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: Sat Aug 30, 2014 9:56 pm Post subject: |
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It is usually a transformer whine, I actually had a cable box switching power supply do the same thing this morning.
The noise can be misleading as to where it's coming from. The only G90 I've heard doing it was actually a coil on the AC input PC board. it could be pretty much any board in the set. Keep swapping boards. try the power supplies next.
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hal
Joined: 28 Nov 2012
Posts: 100
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| Posted: Sat Aug 30, 2014 10:09 pm Post subject: |
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Curt, Are you talking about the "F" power board? If so, I don't have one, my spare one is in the unit. It would be interesting to see how our grid power is doing over summer? BC Hydro and PUD, it was this same time of year that I lost my last "F" board.
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hal
Joined: 28 Nov 2012
Posts: 100
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| Posted: Sun Aug 31, 2014 4:33 am Post subject: |
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Well got the Sony up and running. It was the PB board located under the Blue lens. With that said,
Does anyone have the procedure for setting/adjusting the pots for the HV output. I have had to drop the brightness setting to keep the machine from shutting down.
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