[morzh]

Make sure the person who answered is not a scammer (lots of these there now) and the Trus A S, whoever they are and wherever they are, are a legit place.

[jrblasde]

I’ve asked if they accept PayPal as payment so that I can contest it if the part doesn’t arrive.

[jrblasde]

There’s a lot of different search results for trust auto. I did confirm he takes Venmo, but I’ve got one last test. I asked for the approximate dimensions of the part. That should rule out a scammer. I’ve search extensively online, so I already know that he won’t find any information about this component just by searching online. 

He’s pretty spot on with the price—$40 for the component and shipping. It’s a bit high, because I know that most go for about $25 plus shipping, but it’s not ridiculous. So I’m at least somewhat assured that this is legitimate. I’ll keep you all updated.

[radiorich]

Hello Joseph ,
It sounds like you found a good seller and yes shipping is really expensive !
Sincerely Richard

[jrblasde]

Nope, he can’t tell me the dimensions. Looks like I won’t be buying it.

[jrblasde]

Yesterday's antics aside, here is an update on everything I've accomplished on the 46-480 this week.

I've got all of the parts in hand now, save for the third IF transformer. I chose to start out with the RF chassis. Recall that the wafer switch assembly was a devilish construction. I chose to get that out of the way first. Here's a photo of it during assembly.

   

One thing I needed to do was to make a retaining clip for one of those two inductors. It had been missing a clip, and was just held in place by wiring. It was doing just fine like that, but I'm not here to cut corners! I made one out of an empty Altoids tin (I save these for literally everything).

   

   

The 7F8 socket and the assembly with C404A/B/C are entirely inaccessible with the wafer switch installed into the chassis, so I had to think very carefully about reassembly. I decided that I would install the components which connect the 7F8 socket to the various connections on the wafer switch, and then I soldered the tube socket to this assembly. I continuously kept trying to fit the assembly into place to make sure that the 7F8 socket would line up perfectly with its cutout on the chassis based on the lengths of the leads I installed on the components. I then decided to install wiring which was just barely long enough to solder to the connections on C404A/B/C with the wafer switch assembly held in place and tilted up just a bit for access. With all of these connections made, I could finally bolt the wafer switch into the RF chassis and could also rivet the 7F8 socket to the chassis.

   

   

I've already begun grafting all of the wires coming out of this assembly into the rest of the radio, but today I should have time to finish that. I'm about done with the RF section of the circuit. Next I'll do the IF section, then the AF section, and finally the power supply.

I've got a printout of my schematic which I have pinned to the wall above my workstation. I mark it off as I install components.

   

I've realized as I go along that there were a few minor mistakes. First, I realized that I had a crossing of two wires which I had not marked with a dot to indicate a node. I referred back to the original Philco schematic and concurred that there is not a node at that point. So I added a "jump" symbol to indicate that one wire crosses over the other without creating a node.

   

   

Second, I realized that I had mislabeled the 7F8 heating filament, and had pins 2 and 7 reversed. I caught the reversed pin numbers when looking back at one of my sketches of the wire traces, and consequently noticed the wrong name when I then looked at my schematic.

   

   

Third, I realized that my schematic had two different resistors labeled R408. Recall back to one of the earliest posts I made in this thread. The complete Philco schematic was missing a grid resistor connecting to pin 8 of the 7F8, whereas the enlarged Section 4 portion of the schematic showed one. The enlarged Section 4 schematic properly calls this resistor R409. I am not sure where I found a reference to it being called R408, but there is already an R408. 

   

   

Fourth and final, this was a good one. The original Philco schematic lacked this detail, but the revision notes captured it. I also had depicted it in a sketch of the wire traces while I was disassembling the radio. Essentially, a production change was made to ground pin 1 of S401A(F), so as to ground the push-button trimmer capacitors while in FM mode to prevent oscillation. They accomplished this by creating a hard ground connection at pin 11, and the wafer switch rotor connects pins 11 and 1 while in the FM position. I've decided to add this detail to my schematic, even if the original schematic lacks it. Pin 11 acts as a pole in this application, but also as a throw for another circuit. Hence why you'll see it twice here. I don't like to show it on two different instances of the same switch, but Philco did that in several places on this very schematic so I kept the same styling.

   

I've made these corrections to the Rev 0 and the Rev 1 PDF, since they are applicable to both. I've gone ahead and re-uploaded both here.

[Arran]

Joseph;
Philco seemed to have a lot of errors or omissions on it's schematics, almost from day 1, so I have to wonder about their engineering and drafting departments. They were constantly amending, or modifying things based on whatever parts they had on hand, the 46-1201s being the worst.
Regards
Arran

[jrblasde]

Amen to that! Every time I think I’ve captured them all, I realize that there’s another error. My goal is to finish with an accurate schematic. We’ll see if I catch them all!

Still searching the depths of the universe for that missing IF transformer. I found some links in the Philco Library’s resources page. Today I emailed Wilbur Gilroy and John Kendall to see if they’d happen to have one of these. I also asked if they could recommend any potential leads. I know there’s got to be at least one of these floating around!

In the meantime, I’ll keep soldering the rest of the radio back together. Last night I replaced a couple of capacitors in the first and second IF cans and replaced the brittle wires. Stuffed it all back together with some new fish paper lining the cans!

   

[jrblasde]

I’ve heard back from John and from Wilbur. John had to downsize a few years back, and does not have the part. Wilbur doesn’t have the part available as a loose component, but he’s checking his collection of chassis.

I also found Bob Dobush of Find a Tube. I reached out to him, and he’s checking to see if he may have it. Meanwhile, Wilbur wrote back to me to ask if I knew about the Philco Radio Enthusiasts Facebook page. I did not, but I’ve gone ahead and joined it and made a post there. I haven’t used Facebook in years, so that was a funny experience! Probably the last time I used Facebook was after I got married and my wife asked me to indicate so on my profile 

[morzh]

Yes, it is a good group, because I am in there. 



Seriously, good group. Nice folks. Some are probably here also. And, of course, extra source of information, which never hurts to have.

[jrblasde]

It’s been too cold to solder in the garage the last couple of evenings, but it has allowed me more time to search for the IF transformer. I emailed a shop in Dallas and another in Houston, but no luck. I then stumbled across Jim Koehler in Long Island, New York. I emailed him to to explain the situation and to ask if he may have the part. He wrote back to say that he has since retired from radio servicing, but that he still has a large collection of chassis. He thinks it is possible that he has this part. He’ll let me know after the weather clears enough for him to make it to his warehouse. 

But he was a nice gentleman. Friendly and talkative. He actually said that he’d mail me a copy of a post-war radio service manual that covered models through the 1948 year. He asked about the radios I’d been working on, and decided I would be a good person to read the book. That was very kind of him!