11-01-2005, 09:05 PM
I've just finished replacing all the caps ( leaky Micamolds included) and resistors in a Philco 45, and no radio stations are coming in. I checked all the coils, and I "think" they are ok, all tubes check ok except for one of the 39/44 tubes which read a little low on a couple tube testers I have. I checked the voltages tonight against the Rider data, and get the following readings. What do you folks think? Bad coil somewhere?
6A7: P to K: 271 volts, should be 260
SG to K: G1: 3.23 v, should be 35
G2 : 293v, should be 135
G3 & 5: .220, should be 85
K to F: .228, should be 4.2
39/44 (1st IF): P to K: 270, should be 255
SG to K: 0, should be 75
K to F: .046, should be 3.8
39/44 (2nd IF): P to K: 268, should be 255
SG to K: .046, should be 75
K to F: .046, should be 3.8
The readings for the 80, 42, & 75 all check ok against the Rider's chart. I think the IF transformers are ok. The antenna coil, and oscillator coil, I'm not too confident about after noticing these readings, but both of those coils check ok for continuity, IF, and I say, IF I checked them correctly.I figure that's the problem, though. I hooked a sig. gen. to see if I could get a 460 kc., and 1400 kc. signal through, and nothing.I hooked the sig.gen. to both the antenna clip, and the grid cap of the 6A7. Any thoughts? Thanks!! Ed M.
6A7: P to K: 271 volts, should be 260
SG to K: G1: 3.23 v, should be 35
G2 : 293v, should be 135
G3 & 5: .220, should be 85
K to F: .228, should be 4.2
39/44 (1st IF): P to K: 270, should be 255
SG to K: 0, should be 75
K to F: .046, should be 3.8
39/44 (2nd IF): P to K: 268, should be 255
SG to K: .046, should be 75
K to F: .046, should be 3.8
The readings for the 80, 42, & 75 all check ok against the Rider's chart. I think the IF transformers are ok. The antenna coil, and oscillator coil, I'm not too confident about after noticing these readings, but both of those coils check ok for continuity, IF, and I say, IF I checked them correctly.I figure that's the problem, though. I hooked a sig. gen. to see if I could get a 460 kc., and 1400 kc. signal through, and nothing.I hooked the sig.gen. to both the antenna clip, and the grid cap of the 6A7. Any thoughts? Thanks!! Ed M.
