Re: Ferguson 247T: huge console TV set.
The reason why the line hold control was inoperative was due a leaky 1 mfd Hunts make capacitor C161. Down to 20Kohms! This capacitor is part of the filter network which supplies the control voltage to the reactance valve V15, an EF80. C161 provides the long time delay necessary for the flywheel line sync system to function properly.
V15B, ECC81 is the line oscillator and the A section is a pulse shaper.
In fact all the waxies and Hunts capacitors in the line discriminator had various degrees of leakyness and so the whole lot have been replaced.
A number of capacitors in the vision AGC line had leaks and so those components have been replaced also.
The next stage of the restoration is to reinstall the chassis to find out if all this work has proven worthwhile.
DFWB.
|