Information about the universal chassis that basically seems to combine Wei-Ya 820H and 821H, allowing for tubes with high or low impedance vertical windings.

  • Switch on the left middle is HIGH or LOW impedance. You can adjust in vertical height from either mode on my tube, but it seems to affect pincushion.
  • Pins on the upper right are "WIDE" and "NARROW", selecting between two caps.
  • The wide setting puts another 39nF capacitor in parallel with the existing 39nF (630V393) polypropylene. So I'm going to get a few caps around this number and replace. Logically a slightly capacitance would lead to a wider picture. I'm trying Panasonic ECQE series, 630VDC rated, metallized polyester, 47nF (0.047uF) and 68nF (0.068uF).
  • VR901 is the B+ adjustment. Increasing this will increase the image size. Not known if running this too high or too low is bad for the chassis. Factory setting not known (keep forgetting to check).
Test # Tube H Ohm V Omh Result
1 A51 2.6 11.2 pincushion
2 A48  4.1  15.6  good (minimal curl at top)