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Old 22nd Apr 2015, 9:57 pm   #5
FERNSEH
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Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: HMV 901 restoration.

The raster is restored again. R34 was OK and the fault turned out to be a disconnected wire to the component group board which carries R34.
There still no picture and sound so that will be the next stage of the restoration.

Hi Andy,
That's right, the whole timebase and sync separator assembly is described as the sync unit. Noteworthy is that the sawtooth drives to the scanning coils are described as high sync for the line and low sync for the frame.
It was common practise in many pre-war TV receivers to employ separate sync separators for the line and frame timebase generators. The type of sync separator used in early EMI TV receivers is sometimes called an amplitude filter.

Hi Peter,
It is important to observe the connections of the VIR cable from the power supplier and the focus control. The "hot" cable from the bleeder chain should be the red one and the black lead goes to the control slider.

DFWB.
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