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FERNSEH · 7th Oct 2018, 12:19 am

Hi Nick,
all the usual suspect capacitors in the frame timebase have been replaced. Somehow, I'm thinking that the linearity fault is of my own making.

I might add that after an hours use the EHT voltage reduces to 11KV.
The EHT transformer can doesn't run unduly hot. The 0.22 microfarad boost capacitor has been replaced as well as the 0.01uF coupling capacitor between the oscillator and the grid of the 30P4. The negative going drive waveform is correct @ 100 volts P - P.

Tomorrow I'll check the value of the two series screen feed resistors of the 30P4.
The CRT mask is in good condition. The CRT has to come out for cleaning so then I can determine the material was used to make the mask.

DFWB.

7th Oct 2018, 12:19 am	#20
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Murphy V410 TV Hi Nick, all the usual suspect capacitors in the frame timebase have been replaced. Somehow, I'm thinking that the linearity fault is of my own making. I might add that after an hours use the EHT voltage reduces to 11KV. The EHT transformer can doesn't run unduly hot. The 0.22 microfarad boost capacitor has been replaced as well as the 0.01uF coupling capacitor between the oscillator and the grid of the 30P4. The negative going drive waveform is correct @ 100 volts P - P. Tomorrow I'll check the value of the two series screen feed resistors of the 30P4. The CRT mask is in good condition. The CRT has to come out for cleaning so then I can determine the material was used to make the mask. DFWB.