Well gang I got my philco 624 working! I replaced the power caps in the radio section, checked the other caps in the b unit section, put a couple drops of water in the bias cells, the hooked 'er up to a small 6v lead acid cell and she sprang to life! I can get all the am stations here! Good volume too! But I have a hum.... like if you are humming the letter m.
Any ideas?
Also a second question...There was in the b unit, crumbled yellow stuff in there like a sheild of some sort, is it a sheild for that choke (xfmr) in the b unit?

Hi

Philco 624 uses a vibrator. The vibrator will cause some hum that can't be eliminated.

Be sure that buffer cap 49, .01 mf, has been replaced.

http://www.nostalgiaair.org/PagesByModel/809/M0013809.pdf

These radios did use extra filtering. Chokes 51 and 53 along with caps are filters. Some wires might be shielded? Philco used rubber coated wire that deterioriates in time.

Norm

:Well gang I got my philco 624 working! I replaced the power caps in the radio section, checked the other caps in the b unit section, put a couple drops of water in the bias cells, the hooked 'er up to a small 6v lead acid cell and she sprang to life! I can get all the am stations here! Good volume too! But I have a hum.... like if you are humming the letter m.
:Any ideas?
: Also a second question...There was in the b unit, crumbled yellow stuff in there like a sheild of some sort, is it a sheild for that choke (xfmr) in the b unit?