[Heathkit] SB-610 focus problem

[Dave Cook]

Ok, I'm at my wit's end here and have to beg for some advice. I have two
SB-610s, one of which has very good focus and the other one is significantly
defocused at the edges of the trace. I researching previous questions about
this on this reflector, the suggestion was to refurbish the HF power
components and replace all of the original resistors in the intensity and
focus supply chain. I've done that and the situation did not change at all.
I've even swapped out the CRT with, again, no improvement. Furthermore, I
found that I couldn't quite achieve focus even after replacing all of the
resistors in the HV chain with new ones, and could only improve that by
replacing R510 (3.3 megs) with a 3 meg resistor (three 1 megs in series). I
don't have a way of measuring that high of a voltage with my DVMs, so I'm
not sure if it might be a voltage problem. Any advice would be greatly
appreciated.

 

Thanks and 73,

-- Dave WA0TTN