24-12-2017, 03:39 PM
The Sobell T143. The chassis has been reinstalled into the cabinet. The original metal rectifier still delivers 205 volts to the HT line. Note the position of the mains dropper resistor. It's simply screwed on to the rear CRT support bracket. This set was certainly built on the cheap.
The service notes in the 1953/54 R & T servicing book inform us that the calculated boost HT voltage should be 400volts. In fact it is 395volts in this set. When the voltage readings were taken in 1953 an AVO model 7 multimeter was used. EHT is 12KV.
The AVO 7 is not really suitable for TV servicing. The model 8 is a much better multimeter for TV work because of it's much better 20,000ohms/volt sensitivity.
Geordie McBoyne.
The service notes in the 1953/54 R & T servicing book inform us that the calculated boost HT voltage should be 400volts. In fact it is 395volts in this set. When the voltage readings were taken in 1953 an AVO model 7 multimeter was used. EHT is 12KV.
The AVO 7 is not really suitable for TV servicing. The model 8 is a much better multimeter for TV work because of it's much better 20,000ohms/volt sensitivity.
Geordie McBoyne.
