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FERNSEH · 23rd Apr 2018, 9:07 pm

Hi Nick,
The V17-60 employs a blocking oscillator in the frame timebase. The sawtooth supplied to the grid of the output valve is negative going. This means that the waveform at the anode of the output valve consists of a positive going forward scan and the high amplitude flyback pulse is negative.
In the models V17-53 and V17-70 the sawtooth waveform supplied to the output valve is positive going so the inverted forward scan at the anode of the output valve is negative going and the flyback pulse is positive.
The high amplitude flyback pulse is a result of -V = di/dt.

DFWB.

23rd Apr 2018, 9:07 pm	#10
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: DC Restoration questions Hi Nick, The V17-60 employs a blocking oscillator in the frame timebase. The sawtooth supplied to the grid of the output valve is negative going. This means that the waveform at the anode of the output valve consists of a positive going forward scan and the high amplitude flyback pulse is negative. In the models V17-53 and V17-70 the sawtooth waveform supplied to the output valve is positive going so the inverted forward scan at the anode of the output valve is negative going and the flyback pulse is positive. The high amplitude flyback pulse is a result of -V = di/dt. DFWB.