Sobel T143 evaluation

[Murphyv310]

Pin 4 goes to HT. The odd thing is line op valve screen is fed via the frame op tx secondary and scan coils. This can actually improve picture geometry.
If you are eagle eyed some sets may be perfectly level on the bottom of the raster but slightly out at the top, a tiny amount of field flyback can clear this, it may be down to the scan coil design and cheaper to fix with just a rewire.

[pwdrive]

Pin 4 goes to HT. The odd thing is line op valve screen is fed via the frame op tx secondary and scan coils. This can actually improve picture geometry.
If you are eagle eyed some sets may be perfectly level on the bottom of the raster but slightly out at the top,  a tiny amount of field flyback can clear this,  it may be down to the scan coil design and cheaper to fix with just a rewire.

?

Lawrence.

[Murphyv310]

Did one of these a good number of moons ago and drew out the way the set was wired, the R&TVS was wrong, I mind at the time wiring the screen feed and boost HT end directly to HT and the result was the top of the raster lower on the left than the right.

[pwdrive]

I thought you were referring to the schematic, no worries.

Lawrence.

[Terry]

The other error I pointed out was the 1380 (ohm?) one of the cathode bias resistors in the ECL80 sound circuit, should probably have been listed as 180 ohm.

This was obviously a type setting error when the book was compiled but the other errors are in the schematic which I assume was drawn (badly) by Sobell.