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FERNSEH · 7th Feb 2018, 12:09 pm

Hi Nick,
According to the circuit diagram it would appear that there is no focus control is fitted in the VT161. The CRT focus electrode connection on the tube base is pin 6. The focus voltage comes from a potential divider across the boost HT supply, look for resistors R82 and R83, both 2.2Mohms.
It's possible some later production sets do have a focus control. Trace back the wire to pin 6 of the CRT to confirm if that is so.

Again, according to the service information that the linearity sleeve is once fixed in to position by using the template on the CRT neck requires no further adjustment. Assuming that it is fitted in your set. I often came across sets in which the linearity sleeve had be removed, possibly to increase picture width or a previous repairer didn't know what is was used for so simply discarded it.

DFWB.

7th Feb 2018, 12:09 pm	#9
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Marconiphone VT161 17" TV Hi Nick, According to the circuit diagram it would appear that there is no focus control is fitted in the VT161. The CRT focus electrode connection on the tube base is pin 6. The focus voltage comes from a potential divider across the boost HT supply, look for resistors R82 and R83, both 2.2Mohms. It's possible some later production sets do have a focus control. Trace back the wire to pin 6 of the CRT to confirm if that is so. Again, according to the service information that the linearity sleeve is once fixed in to position by using the template on the CRT neck requires no further adjustment. Assuming that it is fitted in your set. I often came across sets in which the linearity sleeve had be removed, possibly to increase picture width or a previous repairer didn't know what is was used for so simply discarded it. DFWB. Attached Thumbnails