10-18-2018, 11:09 PM
This one?
http://www.nostalgiaair.org/pagesbymodel...003170.pdf
Check the 50C5 for heater/cathode leakage and the 12BE6 too.
If the pressed copper loop got wet (cleaned) or the radio was once stored in a damp location. Place the loop in an oven 150F or so for a couple of hours. Check all the loop winding's for continuity. If the set got a polarized cord, change back to a parallel, that will allow the cord to be reversed to explore the AC line as an RF return.
If the chassis shows even the slightest corrosion and has riveted grounding lugs or lugs on tube socket rings, solder those to the chassis with a high wattage iron to get good wetting of solder.
Do look for devices on the AC power line as a source of hum as Terry suggested. The consider an alignment to bring up the sensitivity. Local noise can cause the AVC to cut back the IF gain...
Most is moot if the home is covered in stucco, brick, stone, aluminum siding or foil vapor barrier, radio in the cellar or surrounded by high rise buildings...
It appears this radio has the troublesome IF cans, well, if the set is working without crashing noises the IF cans will be O.K. for a while longer.
Oh, C16's, the filters, are connected to B- not the chassis...
YMMV
Chas
http://www.nostalgiaair.org/pagesbymodel...003170.pdf
Check the 50C5 for heater/cathode leakage and the 12BE6 too.
If the pressed copper loop got wet (cleaned) or the radio was once stored in a damp location. Place the loop in an oven 150F or so for a couple of hours. Check all the loop winding's for continuity. If the set got a polarized cord, change back to a parallel, that will allow the cord to be reversed to explore the AC line as an RF return.
If the chassis shows even the slightest corrosion and has riveted grounding lugs or lugs on tube socket rings, solder those to the chassis with a high wattage iron to get good wetting of solder.
Do look for devices on the AC power line as a source of hum as Terry suggested. The consider an alignment to bring up the sensitivity. Local noise can cause the AVC to cut back the IF gain...
Most is moot if the home is covered in stucco, brick, stone, aluminum siding or foil vapor barrier, radio in the cellar or surrounded by high rise buildings...
It appears this radio has the troublesome IF cans, well, if the set is working without crashing noises the IF cans will be O.K. for a while longer.
Oh, C16's, the filters, are connected to B- not the chassis...
YMMV
Chas
Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”
