UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

boxdoctor · 27th Feb 2019, 12:34 pm

Hi G.M.,
I would be inclined to check the spark-gaps on the CRT base next for muck in the gaps. Check T202 Pin ! for a dry joint, as this is the source of the flyback blanking voltage (via R247 which could be high or O/C). Also you may simply have the brightness set too high.
Getting back to the video fault, my first candidate for replacement is D103. Unfortunately inside one of the cans. Hard to get at, but worth the effort, as they only cost pence and it's a strong candidate for being faulty. If you haven't found it by this stage, TR106 & 107 and the associated Rs and Cs would need to be investigated next.
As the sync appears dodgy from your remarks, I would think it is most likely to be around the circuitry between L106 and TR106, as the sync is taken off from the collector of TR106. Tony.

27th Feb 2019, 12:34 pm	#18
boxdoctor Rest in Peace Join Date: Sep 2010 Location: Ripley, Derbyshire, UK. Posts: 785	Re: GEC Junior Fineline project. Hi G.M., I would be inclined to check the spark-gaps on the CRT base next for muck in the gaps. Check T202 Pin ! for a dry joint, as this is the source of the flyback blanking voltage (via R247 which could be high or O/C). Also you may simply have the brightness set too high. Getting back to the video fault, my first candidate for replacement is D103. Unfortunately inside one of the cans. Hard to get at, but worth the effort, as they only cost pence and it's a strong candidate for being faulty. If you haven't found it by this stage, TR106 & 107 and the associated Rs and Cs would need to be investigated next. As the sync appears dodgy from your remarks, I would think it is most likely to be around the circuitry between L106 and TR106, as the sync is taken off from the collector of TR106. Tony. Last edited by boxdoctor; 27th Feb 2019 at 12:40 pm.