11-09-2008, 01:51 PM
Jim on another forum sent me the schematic and two pages of instructions / adjustment information.
The unit is a Philco 077.
Now two questions:
1) The schematic below shows an interesting filtering arangement on the 120VAC input to the power supply. I will be using the signal generator to adjust some radios which have a three wire cord and the chassis connected to Earth ground, so that means the chassis of the signal generator will be connected to Earth ground. I would prefer to install a three wire cord and ground the chassis of the signal generator. What changes, if any, should be made to the filtering system?
2) The schematic shows part 22 as a 9,000 ohm resistor parallel to one of the B+ filter electrolytic capacitors (right of center in the schematic). However, the resistor in the set is an old 5,000 ohm unit (blue body, black end, red stripe) which has drifted up to 8,300 ohms. It looks original. Do you think this is a production change, production error, or change by a previous owner (somebody had been inside, as leaked wax from the power transformer had been scraped away from some spots, and the pilot light socket/wiring might have been changed)? Given the higher line voltage these days, would increasing that resistor to 10,000 ohms be a good idea?
[Image: http://i269.photobucket.com/albums/jj77/...ematic.jpg]
The unit is a Philco 077.
Now two questions:
1) The schematic below shows an interesting filtering arangement on the 120VAC input to the power supply. I will be using the signal generator to adjust some radios which have a three wire cord and the chassis connected to Earth ground, so that means the chassis of the signal generator will be connected to Earth ground. I would prefer to install a three wire cord and ground the chassis of the signal generator. What changes, if any, should be made to the filtering system?
2) The schematic shows part 22 as a 9,000 ohm resistor parallel to one of the B+ filter electrolytic capacitors (right of center in the schematic). However, the resistor in the set is an old 5,000 ohm unit (blue body, black end, red stripe) which has drifted up to 8,300 ohms. It looks original. Do you think this is a production change, production error, or change by a previous owner (somebody had been inside, as leaked wax from the power transformer had been scraped away from some spots, and the pilot light socket/wiring might have been changed)? Given the higher line voltage these days, would increasing that resistor to 10,000 ohms be a good idea?
[Image: http://i269.photobucket.com/albums/jj77/...ematic.jpg]
Web site: http://www.masekconsulting.net
Radio Photos: http://www.photobucket.com - album id FStephenMasek
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