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Musicman
Joined: 23 Jun 2019
Posts: 7
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| Posted: Wed Jun 26, 2019 3:55 pm Post subject: Sony VPH 1251Q with buzz and faint vertical rolling line |
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First of all let me say how great it is to be back on the forum. I have just acquired a Sony 1251 for a fantastic price with low hours. The picture is great. Unfortunately there is a buzzing noise which appears to be coming from the area beneath the on/off switch and the power cord plug in. The is also a rolling wave (bottom to top). While a DVD is playing it is almost unnoticeable. Neither of these make the projector unusable, but I know it could be quieter and the picture could be better. Are there any thoughts on these problems? I am no world class expert, but I have done my own work on on a 1272 that I still have which has its own problems (shutting off as soon as it comes on) so I am not scared of tearing into the unit myself to fix it or pulling parts from the 1272 to fix it. I would appreciate any help the form can give me.
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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: Thu Jun 27, 2019 12:29 am Post subject: |
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Disconnect the input. Does the rolling wave still show on the internal test patterns? Sounds like you have a ground loop. the buzzing likely is a transformer lamination that is loose, causing the buzzing.
The 1251 and 1272 power supplies are not interchangable, but some of the parts might be.
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Musicman
Joined: 23 Jun 2019
Posts: 7
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| Posted: Thu Jun 27, 2019 1:44 am Post subject: |
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When the unit is in the warm-up phase the entire screen vibrates. There doesn't appear to be a rolling line. When a video source is introduced the rgbhv input the screen settles down and it's steady, but there is still a line rolling from top to bottom. The line in the picture is most noticeable during black and white movies . The buzzing noise seems to be dependent, as in volume level, depending on what is on the screen. The brighter the picture the intense the buzz seems to be. The darker picture is less intense, but it is still there none the less. It is not a consistent buzzing noise but seems to oscillate up and down sometimes. Is there any help for the power supply, i.e. like finding one to replace it?
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Musicman
Joined: 23 Jun 2019
Posts: 7
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| Posted: Thu Jun 27, 2019 1:48 am Post subject: |
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Yes the line is there during test patterns.
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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: Fri Jul 05, 2019 2:48 am Post subject: |
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Sorry, didn't see the replies.
What should be the same between the two sets are the H and V boards directly under the top cover that covers the tubes. For fun, since the power supplies don't interchange, try swapping those boards, and see if the problem goes away. Don't crack the boards!
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Musicman
Joined: 23 Jun 2019
Posts: 7
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| Posted: Fri Jul 05, 2019 3:17 am Post subject: |
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Thanks for your response.It would have been interesting, but I have as noted in my other post swapped a 1252 for the 1251 with the buzz, but the 1252 blue tube had a lot of burn in it. That's why I had to change out the tube. Maybe I will luck into a the correct tube someday.
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