Jeffrey D Angus wrote:
Waiting on the new 5 watt metal film resistors to correct the
power supply resistors. (replacing the sand ohm and candelohm
resistors.) Still need to pu the 9.1 V zener across the 3V4
(B+) and ground to protect the filaments from over voltage.

I removed the 55/75 Ohm sand bar resistor and replaced it with
a 2500 ohm 50 watt Ohmite rheostat. I Temporarily soldered in
a 1N4007 diode being fed with the AC line voltage and fiddled
with the Ohmit variable to optimize the new resistance values.
Effectively, replace the 55 ohm portion with a 56 ohm 5 watt
metal film resistor, and the 75 ohm portion with a 120 ohm 5
watt metal ohm resistor. The candelohm dual 950 Ohm resistor
was open in both sections, so a 910 ohm 5 watt metal film
resistor for the first section and a 1.0 K ohm 5 watt metal
film resistor for the second section are on order.

Data sheet:
http://www.mouser.com/catalog/specsheets/XC-600044.pdf

The Zenith H500 TO appears to draw approximately 50 mA on the
filament string, and a total of about 75 mA on the B+ when the
volume is up about 2/3 of the way. (I used a Heathkit B+ supply
to directly feed the radio B+ with 106 vdc to measure the current.)

Side note: All the caps were replaced as if they were factory
originals. I.e., desoldered the original leads and removed them,
then reinstalled and soldered the new leads. No hook splices or
quiggs.

Jeff

And now, the shiny new electrolytic capacitors.

220 uF @ 25 v, 2 each 22 uF @ 160 v, 47 uF @ 160 v and a
pair of 33 uF @ 160 v to replace the original 60 uF.

The terminal strips hold them and the new 5 watt resistors
that are on order.

Jeff

Jeffrey D Angus wrote:
Jeffrey D Angus wrote:
Waiting on the new 5 watt metal film resistors to correct the
power supply resistors. (replacing the sand ohm and candelohm
resistors.) Still need to pu the 9.1 V zener across the 3V4
(B+) and ground to protect the filaments from over voltage.

They came in today. Put hem in and oh boy, a radio that works like
new. Also, as pointed out by another tech, I moved the 9.1 V zener
from directly across the filament line to across the last 910 ohm
resistor in the series string. So it's only across the filaments on AC
power, not with the battery.

Jeff