01-03-2021, 06:55 PM
The Library’s ‘Evolution of Philco Model 60’ explains a lot about this little monster.
I have two discrepancy’s from the one I’m working on; a ‘Run 6’ which is the latest one.
1, the coil resistances in (25), the Second IF, measure 33.7 ohms (primary) which is ok, but the Secondary is 45.3 and should be 85 ohms according to the print. I yanked it out of the chassis for inspection, but no obvious blemish.
2, on the IF tube (78) the Screen Grid volts (SG to K) is 75 volts DC. Table 1 wants 120. I swapped the tube for a 6D6, same result.
Will either of these prevent reception of stations?
When Philco changed the Second IF part number on ‘run 6’, is it possible that the 85 ohms was changed to the 45.3 that I’m getting?
I get plenty of noise, which originate Within my humble abode including 460 Kc so maybe the wave trap will work for me!
I have recapped and re-resistered almost everything, and the tubes are good. AF works good, but no RF being mixed or detected. I get lots of noise when touching the mixer grid. With antenna, noise only.
When I put 465 Kc modulated IF to the plate of 78 tube, I get nothing. But then also, there is that low voltage on the screen grid.
I rewound the Antenna coil primary (.7 ohms)
I checked the Osc coil, it’s ok.
Hoping everyone had a great New Years,
Simon
I have two discrepancy’s from the one I’m working on; a ‘Run 6’ which is the latest one.
1, the coil resistances in (25), the Second IF, measure 33.7 ohms (primary) which is ok, but the Secondary is 45.3 and should be 85 ohms according to the print. I yanked it out of the chassis for inspection, but no obvious blemish.
2, on the IF tube (78) the Screen Grid volts (SG to K) is 75 volts DC. Table 1 wants 120. I swapped the tube for a 6D6, same result.
Will either of these prevent reception of stations?
When Philco changed the Second IF part number on ‘run 6’, is it possible that the 85 ohms was changed to the 45.3 that I’m getting?
I get plenty of noise, which originate Within my humble abode including 460 Kc so maybe the wave trap will work for me!
I have recapped and re-resistered almost everything, and the tubes are good. AF works good, but no RF being mixed or detected. I get lots of noise when touching the mixer grid. With antenna, noise only.
When I put 465 Kc modulated IF to the plate of 78 tube, I get nothing. But then also, there is that low voltage on the screen grid.
I rewound the Antenna coil primary (.7 ohms)
I checked the Osc coil, it’s ok.
Hoping everyone had a great New Years,
Simon
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