27" KT-2914 Repair - "Won't Come Up"

zenomorp

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Donor 2015
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This chassis was donated to me in a "won't come up" condition. A few caps had been replaced in an attempt to fix it but it appears that at some point, the chassis had been severely mishandled. First thing I did was attempt to duplicate the issue. It did power up and I had high voltage, but the B+ was only at 78vdc. Began a visual inspection and noticed the film cap at C305 was pushed through the PCB. Fixed that. Then after 'tracing' the 130v B+ output from D121, I found C130 had been hit and broke the positive pad off the trace. Not sure if it happened during the mishandling or when it was replaced, but I fixed that too (replaced the cap as well). Didn't see anything else amiss, so I powered it up again. Success. B+ was 123v with the light bulb as a load on the circuit and it appears to be running normally....until I connected it to a tube.

After connecting it to a tube, I did have an image but it was all gray. No game/test image, the menu wouldn't come up, and nothing I did affected the gray screen. Took it off the tube and put it back on the bench. I had previously looked at the neck board but didn't inspect it closely. I was only concerned about the main board. I never took the plastic cover off the back when I inspected it originally and didn't notice the issue from the front of the board. Well, after removing the plastic from the back, it didn't take long to notice the neck board was severely cracked along with two of the color transistor heat sinks had been hit, which popped the pads off the traces. Fixed those along with the cracks in the board and hooked it all back up.

Presto. A fully working KT-2914. I still need to fully cap and reflow it, but it's working for all three inputs with no issues that I can see. Menu comes up and works as it's supposed to as well. FYI, this chassis is basically the Kortek version of the D9200, so I used a D9200 tube/yoke for testing and it works just fine.
 

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