Re: Stella ST1007U
The short circuit across the HT line has mysteriously disappeared, the reading between the HT line and chassis is 50Kohms, that's OK.
The HT supply electrolytic capacitors C69,C70 and C71 are useless, will not reform so a replacement will have to be found. The capacitor is the type which has the twist tags to secure it to the chassis. A conventional can type capacitor will be used along with a mounting clip.
Clipped out a few black tar capacitors. All found to be leaky. C54, (10,000pF) the line drive capacitor. C57 (56,000pF) and C63 (29,000pF) the boost capacitor and CRT A1 supply smoothing. The frame oscillator, the audio amplifier and focus control are also connected to the A1 supply.
The reason for the unusually high voltage to the audio amplifier is because the anode resistor R26 is 2.7Megohms. R26 along with C28 (560pF) together function as the audio noise limiter. Work that out?
Beery wrote: "I should imagine this set must be quite rare these days. I must smash up more of those common TV22s"
And use the parts to repair those unloved TV24s.
DFWB.
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