Re: Leader lbo 508 oscilloscope help
Colour TV CRT needs around 25kV, too much for a single winding on a 50/60Hz mains transformer. Ferrite cores must need fewer turns (higher flux). Old tube-type colour TV's had no voltage multipler, they used one rectifier and a 25kV flyback winding. Those were huge.
This scope only needs 2kV and it's cheaper to add a 930VAC winding to the power transformer, instead of add another (flyback) transformer and oscillator.
Get rid of the gypsy capacitor meter, it is being fooled by high leakage current. You did measure leakage current or ohms at least on the caps?
The Marcons surely shot. There's five 0.5uF 1500V caps for the -2kVDC rail. C117 does a lot of work and usually goes open-circuit.
Could replace the Marcon's with MKP/PP 0.47uF 1600V or two 1uF in series to get the 1500V.
Colour TV CRT needs around 25kV, too much for a single winding on a 50/60Hz mains transformer. Ferrite cores must need fewer turns (higher flux). Old tube-type colour TV's had no voltage multipler, they used one rectifier and a 25kV flyback winding. Those were huge.
This scope only needs 2kV and it's cheaper to add a 930VAC winding to the power transformer, instead of add another (flyback) transformer and oscillator.
Get rid of the gypsy capacitor meter, it is being fooled by high leakage current. You did measure leakage current or ohms at least on the caps?
The Marcons surely shot. There's five 0.5uF 1500V caps for the -2kVDC rail. C117 does a lot of work and usually goes open-circuit.
Could replace the Marcon's with MKP/PP 0.47uF 1600V or two 1uF in series to get the 1500V.
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