05-04-2021, 03:10 PM
Hi.
Well today I completed the mod to the line output stage.
I now have the 1500, 625 line Jelly-pot installed. The Tuning capacitor is 100pf and the HT to the line stage is dropped by a 500r resistor. This gives me full width, 14Kv EHT and 510v boost. the G2 of the CRT is at 330v WRT Chassis and the focus around 180v WRT Chassis. A supplementary transformer is between the LOPT and the reference phase splitter transformer which is part of the VT4 circuitry.
The Frame linearity pot was leaky and has been replaced. This is of importance to anyone restoring a V4 or VT4 as this fault is hard to diagnose, you get very little control over linearity and the height control just makes the picture stretch badly, If you get stuck with that problem then loosen the controls securing nut lifting the control from the chassis will make the height jump up if its faulty. the leak can be a full short circuit to up to a few meg ohms.
I still need to do other things to the set but so far I am well pleased.
There is some overshoot on screen plus the line jitter still occasionally shows up, I still might try and do away with the supplementary transformer but I now need to get back to the D16T.
Well today I completed the mod to the line output stage.
I now have the 1500, 625 line Jelly-pot installed. The Tuning capacitor is 100pf and the HT to the line stage is dropped by a 500r resistor. This gives me full width, 14Kv EHT and 510v boost. the G2 of the CRT is at 330v WRT Chassis and the focus around 180v WRT Chassis. A supplementary transformer is between the LOPT and the reference phase splitter transformer which is part of the VT4 circuitry.
The Frame linearity pot was leaky and has been replaced. This is of importance to anyone restoring a V4 or VT4 as this fault is hard to diagnose, you get very little control over linearity and the height control just makes the picture stretch badly, If you get stuck with that problem then loosen the controls securing nut lifting the control from the chassis will make the height jump up if its faulty. the leak can be a full short circuit to up to a few meg ohms.
I still need to do other things to the set but so far I am well pleased.
There is some overshoot on screen plus the line jitter still occasionally shows up, I still might try and do away with the supplementary transformer but I now need to get back to the D16T.
