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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Mon Jun 15, 2009 5:37 pm Post subject: Sony 1270 blue stuck on |
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I came down last night after the kids had been watching a movie and noticed that the screen was really blue.
I went into test mode and the blue tube would not cutoff (both red and green would shut down just fine). I turned it on again this morning to check it out real quick and it was still doing it.
Any suggestions on where to start looking for what may be causing this?
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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: Mon Jun 15, 2009 5:39 pm Post subject: |
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Is the blue tube projecting video, or just a bright blank screen? Either way, the screen (G2) control may have drifted somehow, the CA(B) board is bad, or the tube itself shorted out (unlikely).
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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Mon Jun 15, 2009 5:44 pm Post subject: |
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It is a bright blank screen.
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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: Mon Jun 15, 2009 6:34 pm Post subject: |
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Bad Ca (B) board most likely. Check all connections going to it, interchange the RCA video feed on the B board with the green on the CA(G), to see if the video feed is not getting to the blue board, but 95% chance it's a bad CA(B) board.
Cheers!
Curt
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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Mon Jun 15, 2009 6:49 pm Post subject: |
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I'd already tried all the connectors and that did nothing.
In switching the RCA connectors the problem does not follow the board (problem stayed with blue, did not shift to green). I guess I fall in the 5%, since it looks like the CA(B) board is not the problem. That sucks, since the CA(B) board looks like it would be pretty easy to swap out.
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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Mon Jun 15, 2009 7:18 pm Post subject: |
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Any other suggestions on what to look at or does it sound like it is the tube?
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jkruger
Joined: 24 Oct 2007
Posts: 2435
Location: Carlsbad, CA
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| Posted: Mon Jun 15, 2009 7:23 pm Post subject: |
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Isn't it possible that there is some crud shorting the tube inside? Mine did something similar and all it took was some light tapping on the side of the tube to clear it off.
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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Mon Jun 15, 2009 7:36 pm Post subject: |
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| jkruger wrote: | | Isn't it possible that there is some crud shorting the tube inside? Mine did something similar and all it took was some light tapping on the side of the tube to clear it off. |
That is definitely worth a try...
I just wish this had happened a couple of months ago. I could have talked the wife into an upgrade then, but now after being without a job for a month that sure as heck ain't going to happen 
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Mon Jun 15, 2009 7:39 pm Post subject: |
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| Bucketfoot wrote: | I'd already tried all the connectors and that did nothing.
In switching the RCA connectors the problem does not follow the board (problem stayed with blue, did not shift to green). I guess I fall in the 5%, since it looks like the CA(B) board is not the problem. That sucks, since the CA(B) board looks like it would be pretty easy to swap out. |
I think your misunderstanding what Curt said. If you swapped the video feeds of the blue and green and the blue was still blank then the problem is on the CA(B) board.
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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Mon Jun 15, 2009 7:48 pm Post subject: |
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| macgyver655 wrote: | | I think your misunderstanding what Curt said. If you swapped the video feeds of the blue and green and the blue was still blank then the problem is on the CA(B) board. |
I'd love to be wrong here, but that does not follow my experience with troubleshooting. If the board had been the problem I would have expected the problem to transfer to the green tube since that board would now be driving the green tube instead of the blue one.
If I'm missing something here or not understanding the signal path please do let me know.
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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: Mon Jun 15, 2009 8:41 pm Post subject: |
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You can't swap CaG and CAB boards, so the boards still will drive the respective tubes. THe RCA lead sends the signal from the chassis to the CAG and CAB boards, so that will narrow down if the feed to each tube is OK, which I suspect it is.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Mon Jun 15, 2009 8:41 pm Post subject: |
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Ok, then lets just make sure that we are thinking the same video cables first. The video feed cables are the ones coming from the BM board. On the CA(B) board the connector is CAB J1. On the CA(RG) board the green connector would be CAG J1. They are like mini cables. Are these the ones that you tried swapping?
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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Mon Jun 15, 2009 8:53 pm Post subject: |
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Yes, I swapped CAB J1 and CAG J1.
So Curt, is the result you expected if the CA(B) is bad?
If you believe that this is the problem, is this a part that you have?
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Mon Jun 15, 2009 9:03 pm Post subject: |
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| Bucketfoot wrote: | Yes, I swapped CAB J1 and CAG J1.
So Curt, is the result you expected if the CA(B) is bad?
If you believe that this is the problem, is this a part that you have? |
Sorry, but my names not Curt....  and yes its probably the CA(B) board.
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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Mon Jun 15, 2009 9:06 pm Post subject: |
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| macgyver655 wrote: |
Sorry, but my names not Curt.... and yes its probably the CA(B) board. |
I know that 
I was reponding to both you and Curt's post in the same post 
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Mon Jun 15, 2009 9:11 pm Post subject: |
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| Bucketfoot wrote: | | macgyver655 wrote: |
Sorry, but my names not Curt.... and yes its probably the CA(B) board. |
I know that
I was reponding to both you and Curt's post in the same post |
 I'm just messin with ya. I hope Curt has a board for you......
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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: Mon Jun 15, 2009 9:27 pm Post subject: |
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I've got one. Shoot me an email to curtpalme@shaw.ca.
macguyver... I mean.. Curt
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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Mon Jun 15, 2009 11:41 pm Post subject: |
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| Curt Palme wrote: | I've got one. Shoot me an email to curtpalme@shaw.ca.
macguyver... I mean.. Curt |
Email sent
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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Fri Jun 26, 2009 1:46 am Post subject: |
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Ok the new CA(B) board fixed the problem (thanks Curt).
Now I just need to figure out how to get the brightness on the blue toned down some.
I've tried adjusting the G2, but have not been able to get the results I'm looking for so far. So can someone verify that I am doing this correctly.
First, being a 1270 it does not have the test points to measure the G2 voltage. Thus I have been trying the visual process with the pluge signal.
The first thing I did was to put the gain & bias settings all back to their defaults, hit reset and set contrast & brightness to 80/50. I then shorted the connector on the CF2 board, went into test mode, brought up the pluge signal and tried adjusting the "Screen" pot.
My problem is that I cannot get the -5IRE block anywhere close to background.
Can anyone tell me if I am missing something in the process. Either that or does anyone know a way to do this with the voltage rather than visually (maybe one of the pins on the connector)?
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Bucketfoot
Joined: 17 Mar 2006
Posts: 698
Location: Centennial, CO
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| Posted: Mon Jul 06, 2009 2:20 am Post subject: |
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OK, no responses the whole time I was on our road trip. So I guess it's time to bump this back to the top so that someone can hopefully help out on the G2 adjustment
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