Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco 90 1st IF xfrmr question
#1

Discovered that the 1st IF transformer in the Philco 90 early model I am restoring is open on the primary side. Does anyone know if there are any suitable replacements on other Philco models? The secondary reads ~65 ohms, I assume that the primary was the same, as the xfrmr links two 24 tubes.
#2

(03-10-2012, 01:01 AM)TA Forbes Wrote:  Discovered that the 1st IF transformer in the Philco 90 early model I am restoring is open on the primary side. Does anyone know if there are any suitable replacements on other Philco models? The secondary reads ~65 ohms, I assume that the primary was the same, as the xfrmr links two 24 tubes.

I would think that as long as the fq is the same and the mdl 90 doesn't have any extra windings you should be ok. I know that some of the early Philcos use 175kc or 260kc. 262kc was popular among the tube type car radios. As for Philco perhaps a model 70 or 91.
Terry
#3

The early (2-45) and "mid" (1-47) versions of the 90 used a 175 kc IF. The late 90 with push-pull 47 tubes used a 260 kc IF.

A 1st IF transformer from a 111 or 112 should work also, since they also use a 175 kc IF. The part numbers are different but they appear to have the same type of mounting. Worth a try if you have a junk 111 or 112.

I used to have a couple 111/112 junk chassis around here, but I got rid of them a year or so ago. And I don't have a spare dual volume control, either; if I did, I'd send them your way...

--
Ron Ramirez
Ferdinand IN
#4

I tried one from a PP47 112 chassis that measured almost the same resistance- ~65 ohms both primary and secondary. It worked! But the set needs an alignment as the reception is not consistant across the dial.
This set had some wild "interpretive fixing" done on it at some point in time. I had to trace most of the wiring and in several cases re wire these fixes. Additionally, several resistors were drastically out of tolerance. The 1M ohm was reading 2 meg, and all 3 .25 meg were reading .35meg, .45meg, and .6 meg!!

The local distance switch was disconnected, and the leads of it and both 6mFd mershons were loosely twisted together.

It appears that all except one trimmer were screwed down tight. The one that was not was almost all the way out. Soooo, I adjusted them all to more or less center and did minor adjustments using strong local stations for a temporary fix once I got the set to play.

I installed the PP output xfrmr from the console speaker on the cathedral speaker I have, which was formerly for a single 47 output.
#5

Excellent! Good that you had a spare 112 chassis. I looked in the garage yesterday, and sure enough, I don't have my 111/112 parts chassis anymore.

--
Ron Ramirez
Ferdinand IN




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
New Philco Repair Bench
I am sure this is the archive, and not the Chuck's site.morzh — 09:50 PM
Made mistake & did not label connection
It's not like we are good friends with that wire and can tell it from other ptetty identical looking wires. Why'n't you...morzh — 09:49 PM
Made mistake & did not label connection
I'm not sure why that wire wasn't covered in the video. I'm pretty sure the 6A8 won't work until that pin is grounded. Y...RodB — 09:47 PM
Made mistake & did not label connection
You'll have to forgive me, I am not sure what you mean.  Can you explain what you are really saying.  If anyone does not...georgetownjohn — 08:05 PM
Made mistake & did not label connection
Those are details better left to the ones who know. Maybe you disconnected the wrong end of the wire.RodB — 06:22 PM
Made mistake & did not label connection
Maybe this is starting to make some sense in my hard head.  Is this why the wire in question was not in the great Ron Ra...georgetownjohn — 04:34 PM
Made mistake & did not label connection
I was correct with the 6A8 pin connection's, 7 and 8 are connected to ground as well as the tube shield (the broken line...RodB — 02:41 PM
Made mistake & did not label connection
What does the dotted line representing that surrounds the tube in the schematic?georgetownjohn — 02:17 PM
Made mistake & did not label connection
Hello John, I have been there either label got lost or was not labeled ! Sincerely Richardradiorich — 02:15 PM
Made mistake & did not label connection
Sorry, it is a Philco 37-640.  Does that help?--Johngeorgetownjohn — 02:14 PM

[-]
Who's Online
There are currently 2469 online users. [Complete List]
» 2 Member(s) | 2467 Guest(s)
AvatarAvatar

>