25K7000 - High B+

Peale

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25K7000 with really awful solder joints. After correcting the usual suspects, started poking around, since I noted that the fuse was blown.

HOT replaced. C38 replaced. And, since C38 was blown, I started checking other things, as was detailed in my other thread from a couple of years ago regarding a K7000 with a blown C38.

I'd desoldered D13 and D14 (and forgot) and I fired it up with the lightbulb trick to see what it would do (now that I'd replaced a bunch of stuff) and it fired up, though with a lot of ripple (and a really small picture, due to having a B+ of 100VDC).

Back to the bench, soldered D13 and D14 back in, replaced the lightbulb fuse with an actual fuse, fire it back up...and nada. B+ of 145VDC.

More as I find it.
 
I was poking around in all kinds of areas - C69, C36 (to see if the correct caps were installed), resoldered a couple of spotty solder joints...


And then I saw it - one leg of R89 was completely unsoldered. The pad had tarnished, and the joint had just popped right off. Must have happened when I removed the chassis from the frame that last time.

Interestingly enough, I'd forgotten to replace C36 when I resoldered R89, and it still fired up (C69 was still in place) though the picture was kinda screwy.

Seems to be running well now, needs some adjustments, but it's got a good picture, and the B+ is solid @ 131VDC.
 
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