05-28-2018, 05:59 PM
May 28.
I started the day by finishing up the sub-base:
[Image: http://www.philcoradio.com/images/phorum...90_079.jpg]
I replaced the RF tube socket, wired it up, and replaced resistor (38).
Then I turned my attention to the oscillator unit.
I checked all of the coils and was greatly dismayed to find that the band 5 primary of coil (37), which is two coils on one form and serves as oscillator coil for bands 4 and 5, was open!
However...
I then discovered, quite by accident, that one lead going to that coil was broken!
I tested for continuity again and (happily) found that the winding in question was good after all. Whew, what a relief!
So I carefully soldered a piece of wire to the little "nub" left on the coil form, the other end going to terminal E12 on the band switch.
I replaced all but a few wires on the oscillator unit, as well as resistors (33) and (43) as well as another resistor, not on the schematic but listed in one of Philco's "Changes in Models" bulletins (15K) which is connected across the band 5 oscillator coil primary.
Here's how it looks now.
[Image: http://www.philcoradio.com/images/phorum...90_080.jpg]
Now it is time to start reassembling the RF unit, a section at a time. But first I shall need to carefully clean those switch sections with DeoxIT.
Back to work tomorrow, so progress will necessarily slow to a crawl until next weekend. I don't have much spare time at all on work nights. Nevertheless, I do hope to have the RF unit finished in a day or two, install it in the 38-690 tuner chassis, and try the radio out again in the next few days.
I started the day by finishing up the sub-base:
[Image: http://www.philcoradio.com/images/phorum...90_079.jpg]
I replaced the RF tube socket, wired it up, and replaced resistor (38).
Then I turned my attention to the oscillator unit.
I checked all of the coils and was greatly dismayed to find that the band 5 primary of coil (37), which is two coils on one form and serves as oscillator coil for bands 4 and 5, was open!
However...
I then discovered, quite by accident, that one lead going to that coil was broken!
I tested for continuity again and (happily) found that the winding in question was good after all. Whew, what a relief!
So I carefully soldered a piece of wire to the little "nub" left on the coil form, the other end going to terminal E12 on the band switch.
I replaced all but a few wires on the oscillator unit, as well as resistors (33) and (43) as well as another resistor, not on the schematic but listed in one of Philco's "Changes in Models" bulletins (15K) which is connected across the band 5 oscillator coil primary.
Here's how it looks now.
[Image: http://www.philcoradio.com/images/phorum...90_080.jpg]
Now it is time to start reassembling the RF unit, a section at a time. But first I shall need to carefully clean those switch sections with DeoxIT.
Back to work tomorrow, so progress will necessarily slow to a crawl until next weekend. I don't have much spare time at all on work nights. Nevertheless, I do hope to have the RF unit finished in a day or two, install it in the 38-690 tuner chassis, and try the radio out again in the next few days.
--
Ron Ramirez
Ferdinand IN