Philco 50-701

[Gregb]

I am working on my Philco 50-701 at the moment and overall it is working great but the retrace lines are a little annoying. Has anyone added retrace blanking to this model and would you be willing to share what you did?
Thanks

Gregb

[bandersen]

Perhaps you can adapt the 19A1 Admiral retrace modification. That design has the video feed into the cathode while the grid controls brightness. http://antiqueradio.org/art/Admiral1...ingCircuit.jpg

The 50-701/2 uses the grid for video and cathode for brightness. That means you'll need a positive pulse on the cathode for blanking. Anyone try this ?

[Gregb]

Thanks Bob, yes that is my question. I have used that circuit for my Admiral set and it works fine. Anyone know how I can modify this to work in my Philco? I have finished re-capping and a number of resistors and it works great other than the retrace lines are a little annoying. I can adjust them out but would be nice to get a little more brightness.

Gregb

[Electronic M]

You can always try a RC decade box, and try different polarities of vertical waveform different RC values, and different points in the video chain until you get it right....When a pre-designed solution is not available decade box engineering can work wonders.