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FERNSEH · 22nd Apr 2015, 3:48 pm

And here it is, the HMV 901. This job is not going to be as easy as the Marconi 702. For starters there is no raster, the 5KV EHT is apparent at the anode cap of the CRT, so at least there are no concerns about the mains derived EHT supply.
So the first task is to get the CRT screen alluminated. Possible causes of the no raster fault is no focus volts or the biasing of the CRT is incorrect causing the CRT to be cut-off. The brightness control is in the cathode circuit of the CRT. 20 volts of postive going video is supplied to the CRT grid.

The cabinet presentation is considered by most as being not as attractive as the Marconi version.

DFWB.

22nd Apr 2015, 3:48 pm	#1
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	HMV 901 restoration. And here it is, the HMV 901. This job is not going to be as easy as the Marconi 702. For starters there is no raster, the 5KV EHT is apparent at the anode cap of the CRT, so at least there are no concerns about the mains derived EHT supply. So the first task is to get the CRT screen alluminated. Possible causes of the no raster fault is no focus volts or the biasing of the CRT is incorrect causing the CRT to be cut-off. The brightness control is in the cathode circuit of the CRT. 20 volts of postive going video is supplied to the CRT grid. The cabinet presentation is considered by most as being not as attractive as the Marconi version. DFWB. Attached Thumbnails