6 hours ago
It has but not RF as I don't have the dial yet.
Philco 38-2 Low Volume
6 hours ago
It has but not RF as I don't have the dial yet.
6 hours ago
RF does not matter: IF does. This RF transformer is RF; if not aligned, it will attenuate the signal.
Make sure it is peaked, both sections. And, then try to remove the tube 6H6 and see if it affects the loudness in the tracer. You could also try to increase C45 to 1uF, see if it makes things better. The time constant of this filter is in audio frequency. Not sure why. People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
5 hours ago
Using the tracer, when I pull the 6H6 it gets a little louder on the 6R7. Didn't seem to change at all on the 6K7 tube.
4 hours ago
Did you have a cap in series with the signal tracer probe? Is there a diode in series with the probe? If yes to both then you may have to turn down the gain of the tracer. If no cap, then you may have been overdriving the tracer with B+
Ohm the secondary. It should be quite low, about 8 Ohm. There is a good possibility that it is open. If you connect the tracer to either diode plate of the detector / 1st AF Amp Tube (6R7), i suspect that the sound level will be low. Isolating the ground on the probe with a large cap (like 0.1uF, connect ground side of the probe to the green wire on the IF Out trans and probe the brown wire with a diode in the circuit. The signal should be quite loud. Note that there are 2 100pF caps, 39A and 39B, each between ground and either side of R43. These are likely mica and, although rare for them to fail, it may still be possible. Excessive leakage of either cap will definitely lower the volume and AVC signal. Hope this helps. "Do Justly, love Mercy and walk humbly with your God"- Micah 6:8 Best Regards, MrFixr55
4 hours ago
C45 serves as a decoupling cap for the B+ for the IF Stage. If all components test good, revisit the IF and Local Osc alignment. Remember that the oscillator must be 470KHz above the desired station. If this cannot be adjusted to be within spec, you may have to align the IF not to 470 KHz but to the difference that you actually get between the local oscillator frequency and the station frequency.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8 Best Regards, MrFixr55
3 hours ago
MrFixr55 I am using the second schematic, the one with the X parts as that is my radio. The 39A and B are 16X, containing 110pf caps that are in a bakelite block. I had already changed them with silver micas. Having to use two different schematics sure makes this harder. Some sections are on one and some the other.
The coils in both IFs are all good. I had checked them a while ago. No caps in series with probes. I will try again with caps. I was told a while ago there were blocking caps in the tracer. Not sure about the ground though. I don't know how to measure the difference frequency. I don't have a scope so the best I might do is a frequency counter but I would not know how to do that either. As for the non peaking compensator I'm wondering if the internal cap might be bad. The schematic does not list the value for them except for 2XD (110pf) which I changed. If RF alignment is off could that render the AVC inactive? I'm wondering if I should put the radio aside until I get my dial and then I can do the RF alignment.
2 hours ago
BTW, when you do all that, is your magnetic tuning ON or OFF?
Should be OFF. People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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