[Guest]

All,
Thank you for all the good input. I wanted to provide additional data for your expert evaluation. My goal here is to have you evaluate my data and
conclusions, and let me know if I've missed something, as this is a learning exercise for me.

Again, everything is referenced to this schematic:

http://www.philcoradio.com/tech/images/70a.jpg

Work Performed
--------------
1) I have replaced both electrolytic (2 x 10uF) and all condenser block capacitors (exact uF values). One exception is the tone control cap (48). Just
realized I missed it.
2) I replaced the following resistors, which were out: 29, 30, 32 and 24, with 250K, 50K, 250K and 50K, respectively. All others were in tolerance.

Resistance Measurements
-----------------------
Schematic Actual
--------- ------
(36) C->D (Field Coil) 3100 3085
(37) D->E 1060 1126
(37) E->F 2300 2480
(37) F->G (Volume Control) 250 226
(37) G -> Chassis 70 76
(37) Chassis -> H 240 250


Voltage to chassis (with 115VAC from variac)
--------------------------------------------

Point Actual
----- ------
C 277
D 147 (... 130 drop through field coil, or about 42mA)
E 103
F 11.5
G 3.1
Chassis 0.0 (I know ... just being thorough ... :-)
H -19


Conclusions
-----------
1) All resistance measurements look good to me.
2) Voltage (277) at C seems high. I see this voltage at the plate for the following tubes (left to right on schematic): first three 24A (RF, D, IF) and 47.
Max plate voltage should be 250 according to specifications for 24A and 47 tubes. I am using replacement 24As; the originals in these positions tested low,
and the bottoms of the plates were a little blued. I'm not sure why I'm not seeing some drop through the OPT primary for the 47.
3) The field coil is rated for 40mA through 3100 ohms, or a voltage drop of 123.6. I'm seeing 130. After 5 min. of play, the field coil is barely warm to
the touch.
4) Voltage on the plate of the 27 is 66. Not sure what to make of this, but seems reasonable since the voltage at E (103) goes through a 13K resistor to get
there.
5) Voltage on the plate of the other 24A (2nd D) is 225. Interestingly, the original 24A in this position tested good with no blueing. If I'm seeing this
right, the voltage from C would be dropped through resistors 30 and 29 (50K and 250K) ... again, not sure what to make of this.

Performance and Thoughts
------------------------
- With a 12 ft. wire on the antenna, in my basement, I get local AM stations just fine (590 and 1560), and they are aligned on the dial.
- I can drop the line voltage to about 110VAC with no noticeable loss of performance ... just a little volume. I am tempted to bleed voltage off C to
chassis through a resistor to drop the voltage; especially since the set will actually see about 120VAC when plugged into the wall.
- The set has a lot of volume. At the lowest setting there is just a very small amount of speaker white noise ... no hum at all.
- I can receive local AM, and they sound very good, but the volume fades in and out over the course of about one minute. When out, you can barely hear the
station, then it starts coming back and returns to sounding very good.
- All of this is without the ground clip hooked to anything. If I plug the variac directly into the wall, the chassis of the variac is grounded. The
voltage between the variac chassis and radio chassis (again, with 115VAC input) is 56.6VAC ... again, not sure what to make of this. If I move the red lead
of my DMM (Fluke 73III) to the 300mA plug, and set to measure AC amps, I get 0.61(uA?) ... maybe this is acceptable?

I welcome any and all input ... thanks again for helping me learn,
M100C