VDR's were a mystery part for us. Only remember changing
them in Zeniths both the vert & HV regulator. In 40 yrs
never learned how to test them. they were cheap so if you
had the symptom you just change them. Dont know of any
color codes, they were all just colored until later years when
they were a nice blue color with a Zenith part number.
BTW those OEM & NOS unopened go bad on the shelf its been
found.
BTW #2 M5 is probably like a Zenith integrator. The resistor
showing a cap symbol. It is 2 resistors with 3 caps. High failure
rate in Zeniths.
BTW #3 If you have total loss of vert I would not suspect the VDR.
The readings you got on the xfrmer point to it. Try hanging in
any old one from a B&W & see if it opens up.
73 Zeno
