"WayneJ" wrote in message
newsp.vtlmouo7natzq9@dellilah...

Hi Fabe,

You probably know this, but the parts that look like RF coils are wire
wound "precision" resistors. No RF is used in these testers. They are
wound with resistance wire, higher Ohms/foot than copper, so rewinding
with the same number of turns of the same size copper wire will give
the wrong resistance.

Modern metal film 1% resistors can be used to replace any of them, be
sure the wattage is correct. If you want the same appearance to make
an original appearing restoration you will need to use the kind of
tricks used to make old radio restorations appear accurate when using
modern components.

You might need to parallel a couple of values to get the exact value
Hickok used but that is not likely necessary. This tester was
considered to be accurate to about 10% when new.

WayneJ


Excellent advice, Wayne.

The Hickok 533A manual at Bama lists these "spool" resistors. These
precision spool resistors were also used in analog computers. Modern
metal film 1% resistors should work well to replace them.

18670-105RESISTOR, Spool:small, 10 ohmsR9
18670-118RESISTOR, Spool:small, 135 ohmsR28
18670-412RESISTOR, Spool:medium, 41 ohmsR15, R17
18670-417RESISTOR, Spool:medium, 109 ohmsR16, R18
18670-418RESISTOR, Spool:medium, 150 ohmsR14
18679-114RESISTOR, Spool:double, 122 and 32 ohmsR19, R20


73, Dr. Barry L. Ornitz WA4VZQ

P.S. - the more recent tube testers did use ferrite beads on the long
internal leads to suppress RF oscillation.