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City: Durham
State, Province, Country: NC
After my interpretation of the schematic and physical layout, I have attempted to number the lugs on the schematic. At this point, I currently don't believe I have an open coil.
Lugs 1-3 : feedback coil (small band on the bottom outside) 7.0 ohms
Lugs 2-4 : primary with a common connection(4) to the secondary winding 4.5 ohms
Lugs 4-5 : secondary with a common connection (4) to the primary winding 4.9 ohms
If I'm reading this correctly, the feedback coil (considered the secondary outer winding) should read 15.7 ohms but actually reads 7.0 ohms
My thought is just to rewind the feedback coil and hope for higher ohms.
Thoughts anyone would be appreciated
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City: S. Dartmouth
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Try using another meter, a VOM is recommended. The readings, now, are not really out of line. Re-solder the terminals of the observed offending coil.
Check the capacitors in the circuit. Schematic seems to indicate four variable condensers. At least two are the main tuning condenser and its (mounted) compression trimmer. Any leakage from damage, corrosion or dust can kill the oscillator.
NOT associated with any particular radio is that the insulators for the stator of tuning variable condensers have been known to leak. Poor electro-mechanical connections to the rotor can also be troublesome.
I see no copper corrosion but, the decaying celluloid can be a source of low resistance by shorting turns of the tickler, unseen on the inside of the winding.
The tickler is at cathode potential, any leakage to the other windings which reference ground, will carry some of the total plate current.
GL
Chas
Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”
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If my memory serves me right (and this is not always the case), is my recollection correct that the R18, a 15K resistor, had sometimes go down to 10K to oscillate?
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.
Posts: 15,407
Threads: 535
Joined: Oct 2011
City: Jackson, NJ
One thing I did not hear from you (sorry if I missed it):
1. Have all the tubular paper caps been replaced?
2. Have all the resistors been checke for being within some reasonable boundaries from the specified values?
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.