Repair Log: G07 - Dim image, raster lines, known good CRT...

Hi -

Going to post some of the more unusual G07 repair logs as I come across them.

G07 - Taken in for a repair/rebuild. Had obvious "attempted repair(s)".

Installed new caps, HOT, flyback, soldering touch-ups on neck board, all potentiometers. B+ adjusted to solid 120.4V, monitor working, sharp image. However, on-screen image seemed to have the raster lines too bright on-screen. By the time the rasters were removed using the screen control, the image was very dim. On the neck board, G1 was about 40V too high (usual 475V was around 510V), and BK/RK/GK were also too high by the same margin.

Tube was "known good" - could swap another G07 chassis and my test CRT was nice and bright.

Diagnosis: X501 (incorrect value). Even though I had pulled and tested the transistor in my initial testing, I did not cross reference the value. Should be a TIP47 or NTE198.

Hope this helps someone down the road. Certainly not a "common" issue to come across, as most people recommend rejuventating a "dim" tube, but in this case, that would not have changed the end result.

Best regards,
Scott...

http://www.revisionx.com


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Relevant Pages

  • Re: Repair Log: G07 - Dim image, raster lines, known good CRT...
    ... Going to post some of the more unusual G07 repair logs as I come across them. ... On the neck board, G1 was about 40V too high, and BK/RK/GK were also too high by the same margin. ... Certainly not a "common" issue to come across, as most people recommend rejuventating a "dim" tube, but in this case, that would not have changed the end result. ... You never know when you're even back to the original problem, sometimes you have several layers of created problems on top of what it had to begin with. ...
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    ... when remove the red running from the flyback to the Tube. ... The chassis was in very nice shape and the monitor had a nice picture. ... check the neck board for cracked traces though. ... John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 Call 872-5757 or Fax 872-2010 ...
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