03-21-2012, 06:53 AM
[quote='morzh' pid='26281' dateline='1331961277']
Today decided to look at the sch again - the radio played not loud enough.
Sure enough, in the 2nd detector I soldered the load (10K resistor) to Screen Grid, not to the Plate.
Now this thing is really loud.
It pulls only one station, the loudest one around.
Still have not tuned it.
Q1: Anyone knows of tuning procedure, and where I can find a good guide for it (tuning the IF filter etc, tuning the Regen. of the 2nd detector).
Q2: The Det. oscillator has a mica cap of 710pF / 10K resistor feedback in the Cathode. Has anyone needed to replace those? The 10K resistor measures 11.4K, the cap, of course, cannot be measured without desoldering.
Tuneup is the same as all superhets. Adjust IF trimmers for peak at IF frequency (470kc)With the dial set at 1400kc, two trimmers on the tuning cap adj for loudest signal at 1400kc. Adjust the regeneration control till it squeals then back it down a 1/4 turn.
If the set is working I wouldn't bother to pull the IF can apart, unless you wanted to change the grid leak resistor.
Terry
Today decided to look at the sch again - the radio played not loud enough.
Sure enough, in the 2nd detector I soldered the load (10K resistor) to Screen Grid, not to the Plate.
Now this thing is really loud.
It pulls only one station, the loudest one around.
Still have not tuned it.
Q1: Anyone knows of tuning procedure, and where I can find a good guide for it (tuning the IF filter etc, tuning the Regen. of the 2nd detector).
Q2: The Det. oscillator has a mica cap of 710pF / 10K resistor feedback in the Cathode. Has anyone needed to replace those? The 10K resistor measures 11.4K, the cap, of course, cannot be measured without desoldering.
Tuneup is the same as all superhets. Adjust IF trimmers for peak at IF frequency (470kc)With the dial set at 1400kc, two trimmers on the tuning cap adj for loudest signal at 1400kc. Adjust the regeneration control till it squeals then back it down a 1/4 turn.
If the set is working I wouldn't bother to pull the IF can apart, unless you wanted to change the grid leak resistor.
Terry
