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Model 80 Chassis/Tuner Isolation
#9

Hi Terry,

Thanks for your help.
I haven't played with tube audio since I was in my 20's grew up on Heathkits, ELCO, Dynakits etc.
Have worked for over 40 years in Electronics, I thought this would be a fun hobby Icon_smile

This radio was "restored" back in 1990, noticed one of the tubes was a 44, not a 36
Here are before and after photos. I opened up the Bakelite caps and replaced the old caps.
       

My test equipment I have consists of:
Fluke 82 RMS Mulitmeter
60Mhz Tek analog scope
B&K 2050 RF signal generator
Tek Frequency counter
Heathkit AV-3 Audio analog VTVM (not very accurate, but great for tuning)
Knight 600 tube tester

I have performed the tuning procedure about 10 times, swept the IF, it seems to like 450KC better than 460KC.

Hooked the RF generator to the grid on top of Det/ Osc tube, removed clip first. also attached a 560 ohm to gnd per John Rider for bias.

Tuned using John Riders paper on Aligning Philco Radios and Philco Service Bulletin 120E.
The radio seems to like 450KC vs 460KC.
The radio seems to match the latest schematic shown with the values.

I have turned the sensitivity control till it squeals and backed it off 1/4 turn. 

The radio seems to only pull in one station at 1300KC, and very weak station at 780KC
I have a little Grundig M400 AM/FM SW mini radio, it seems to pull in these stations ok.
The Philco is very noisy and a bit distorted/ garbled. I hear some of the same noise on the Gundig.

I live south of Reno, south of Carson City in Carson Valley.
Since the Gundig only seems to pull in 2 stations, perhaps this is the best I can hope for from the Philco since I live in a valley?
I have a 25 ft wire antenna running outside.
I do notice that the kitchen LED lights seem to cause a lot of noise in the Philco.

The radio is nice and quiet with the volume turned down, can't even tell it's on.

Thanks for your help
Lewis


Messages In This Thread
Model 80 Chassis/Tuner Isolation - by Lewiss - 09-25-2018, 11:10 PM
RE: Model 80 Chassis/Tuner Isolation - by morzh - 09-26-2018, 08:07 AM
RE: Model 80 Chassis/Tuner Isolation - by Lewiss - 09-26-2018, 01:25 PM
RE: Model 80 Chassis/Tuner Isolation - by morzh - 09-26-2018, 01:33 PM
RE: Model 80 Chassis/Tuner Isolation - by Lewiss - 10-06-2018, 03:05 PM
RE: Model 80, 1st restore in over 40 years - by Lewiss - 10-06-2018, 06:49 PM
RE: Model 80 Chassis/Tuner Isolation - by Lewiss - 10-07-2018, 05:10 PM



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