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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Wed Mar 16, 2011 8:38 pm Post subject: Another NEC 9PG plain problem |
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I got this machine for testing purposes, but it is not working properly.
I got some spare parts to test in this machine (eg. PWC-3712B conv board)
I have 3 set of system boards, 3 set of gain ctl, and video out boards.
There is no picture on the pj, I mean menu is working well, but no picture from input or internal test pattern. The input information shows the hfreq. and vfreq. I can turn on and off the AKB(can see the line), and only see the raster, but brightness and contrast have only minimal effect on it. Measured with oscilloscope that the input signal goes through the gain ctl bd. I've tried all variations of the system boards with no effect, and even changed gain ctl and video out board.
What can cause 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: Wed Mar 16, 2011 9:05 pm Post subject: |
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My test set did this, and it was the video output board that was bad. That's the board with the big heatsink on it that the CRT sockets connect to.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Thu Mar 17, 2011 5:41 pm Post subject: |
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Then all three video out boards are failed... no difference between them
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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 Mar 17, 2011 6:58 pm Post subject: |
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No, the board that drives the CRT sockets. THe video amplifiers are on that board.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Thu Mar 17, 2011 7:05 pm Post subject: |
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Yeah I know, I have also three pieces of the drive board with the heatsink, I've changed them but no difference, that's why I suggest they all bad.
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