I decided to commit to buying the other 46-480. $75 isn’t terrible, considering that they’ll be traveling through Oklahoma on a vacation in a few weeks and I can meet them to get it at a town about an hour and 15 minutes west of Tulsa. Saves me from driving up near Kansas City where it is now.
I reached back out to the guy I saw on the Philco Radio Enthusiasts page, and I think he’s interested in the output transformer from this set. He asked what I’d sell it for, and I said $20. We’ll see if he accepts. I’m not looking to get rich off of these parts. I’d rather know that they are going to be used by someone looking for that last crucial component.
Once I have the console, I’ll create a listing here with all of the parts which are available. Based upon the photos, the chassis looks clean. The cabinet is in serious need of refinishing, but it looks solid.
Hahaha, very true! In any event, the photo didn’t show any substantial rust on the top side of the chassis. It also clearly displayed the IF transformer for which I’ve been searching.
I’ll get you all some better information once I have it in my possession.
Good afternoon, folks! A wind of good luck has come! I’ve been quietly waiting to go get the junker 46-480, but I’ve just gotten an email from Mark Oppat. After a couple of months of looking, he found the IF can I need! He had me fill out an order form, and now he’ll ship it to me. I am thrilled!
Aside from that, here’s my progress. I’ve kept at it, but have slowed down a bit lately while I repaint the exterior of my house. I’d estimate that I am about 2/3 of the way done reassembling.
I forgot to make mention of it the other day, but last week I corrected another error on my schematic (applies to both Revs 0 and 1). I had thought, from looking at the Philco schematic, that pins 4 and 6 of the 7H7 used as the second IF amp were connected. I realized when comparing against my physical wiring notes that they are not. I also verified using the Rider's version of the schematic that they are not tied together. I'm sure that the original Philco schematic was correct, but this particular crossing was blurry and it looked to me to be a node. Anyway, I've attached the corrected schematics.
I have never hear of the Suppressor Grid to be used in parallel with the Grid.
SG sole purpose is to be anti-dynatron grid, which is suppressing the secondary emission.
Which usually makes it connecting to GND or K.
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.
Not only would it not make sense for a suppressor grid to be tied to the (signal) grid, but both would be tied to ground in this case killing the input from the previous IF transformer. Maybe there is a circuit out there that makes use of the suppressor grid for something other then eliminating secondary emission, but it's probably in some one tube home brew project. I did run into a similar wiring error in a Phonola though, they tied the suppressor grid to chassis ground whilst the cathode was floating above ground, and this was a wiring error from the factory. I'm not sure what difference this would have made to the performance of the 6K7 IF amplifier tube, but there was evidence that the tube had been changed most recently in the 1970s since it had the RCA block letter logo on it.
Regards
Arran
I have noticed that the AVC line in some pre-war Philcos is connected to the suppressor grid, as well as the control grid, of the first IF. The 41-221 is an example. Maybe that's what this is.
41-221 is above. By "control grid" you probably mean screen grid, that of the 2nd IF.
I'd like for someone to verify this in citu, as unless that is verified, I'd almost think this is a schematic misprint.
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.
Both these radios seem to connect the SG to AVC. Which I am not sure why, but then the AVC potential is close enough to K.
But it will not connect to Control Grid.
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.
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