09-10-2021, 09:27 PM
(This post was last modified: 09-10-2021, 09:29 PM by Geordie McBoyne.)
Frank's Cossor 54 motivated me to try out my set today. First result was a spot in the centre of the screen. A partial short circuit across the HT supply was caused by the lid of one the IF stages screening boxes coming into contact with a component in the HT circuit. Lifted the lid and short circuit gone.
Now have a dim raster. The CRT isn't good. There's a fault in the signals circuits somewhere. The RF circuits resemble those in the model 1210 and the post-war model 900.
The frame oscillator is a Cossor type 4TP, a valve that's just about impossible to find. Andrew Beer has made for this set a plug-in replacement which employs an ECL80. A miniature auto transformer in the B7 base provides the 6.3volt heaters for the ECL80.
Geordie McBoyne.
Now have a dim raster. The CRT isn't good. There's a fault in the signals circuits somewhere. The RF circuits resemble those in the model 1210 and the post-war model 900.
The frame oscillator is a Cossor type 4TP, a valve that's just about impossible to find. Andrew Beer has made for this set a plug-in replacement which employs an ECL80. A miniature auto transformer in the B7 base provides the 6.3volt heaters for the ECL80.
Geordie McBoyne.
