TRK12/120 Restoration

[dtvmcdonald]

Another note for TRK12 users:

While I did not notice it on program material, I noticed
a considerable (say 1/8 or 3/16 inch) bending of vertical lines,
moving at the usual 60 vs 59.94 Hz beat frequency. This could only be from
hum pickup from the heater power, or magnetic fields, since
it clearly was 60 Hz hum, not 120 Hz.

Installation of a cylinderical Mumetal shield on the
area between the socket of my radar tube and the yoke cured it,
so it was magnetic. This was a shield made for a
2 inch photomultiplier.

My experience has been that for these noncritical applications
a 1/16 or 1/8 inch wall plain steel tube , degaussed first,
would work fine.