Re: Baird Garrick
Hi all,
Last night I drew up the circuit of the timebase section of the Baird Garrick as it currently is, with flyback EHT. See the attached PDF.
The focusing arrangement is interesting with a constant current sink which works by comparing the voltage across VR6 with a 100V reference provided by neon stabiliser V1. The grounded grid of the SP42 looks very odd at first.
Also note the DC restoration diode on the CRT grid, however no such diode appears on the cathode circuit. Remember that the black and red wires from the vision receiver provide a negative and a positive video output.
When the set was adapted to flyback EHT, VR4, L3 and C4 were added together with V8 and C17.
I don't know the actual value of wirewound screen feed resistor R8 as it has overheated, loosing all of its outer cement and causing the resistance wire to spring out. I will attempt to measure what is left.
The frame circuit is very similar to the Baird T18.
Cheers
Andy
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