Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

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

41-280, -286, -287, -290 1st IF Xfmr
#3

Arran;

Thanks for that response. The schematic does seem to indicate that there is an adjustable ferrite slug present. It shows the adjustable trimmer capacitor on the secondary feeding the grid of the 1st IF amplifier tube. Your set appears to match the indicated circuit on this schematic.

I have a Philco 40-201 I restored and it is somewhat similar, in that it uses a broadly tuned RF amplifier (1232 pentode) followed by a 7J7 mixer-oscillator. The 1st IF transformer in it has two ferrite adjustable slugs plus a tertiary winding feeding the suppressor grid of the 7B7 1st IF amplifier tube. So my 40-201 has some significant differences, but similarities at the same time. It appears to be another design to incorporate higher selectivity in the IF circuitry. Philco began to use the broadly tuned RF amplifier on many models for a number of years.

Joe


Messages In This Thread
RE: 41-280, -286, -287, -290 1st IF Xfmr - by Joeztech - 10-20-2016, 07:11 AM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Rogers Majestic R-646
Today I finished inspecting all the parts. The result is not very pleasing. The first positive news: 1) The power tr...Vlad95 — 11:40 PM
HiFi (Chifi) tube amp build - but my own design.
Well, found muh culprit. After using socket test adapters and finding voltages all ok, swapping 6V6s, no avail, swapped ...TV MAN — 11:18 PM
HiFi (Chifi) tube amp build - but my own design.
Well, maybe - maybe not  :lol: It's been an interesting project so far! Something so simple, yet so cranky. The 1st one ...TV MAN — 05:12 PM
1949 Motorola 5A9M
Haven't thought of Burgess batteres in a while  https://www.radionostalgia.ca/lib/Images/battery/us/burgess1D.jpgi ...Vlad95 — 03:50 PM
Philco Model 16 wiring question
Measure the voltages first, just in case.morzh — 02:19 PM
1949 Motorola 5A9M
Haven't thought of Burgess batteries in a while Mr. Fixer. Boston Edison always used Burgess in their Bright Star yellow...Paul Philco322 — 02:17 PM
1949 Motorola 5A9M
Thanks Sam. I'll let you know. I can probably scare some up from the local radio club.klondike98 — 02:07 PM
Philco 89 Code 123 Osc Coil
Hello,  I thought I would post my findings on my bad oscillator tickler coil. There were 27 turns on the outer coil b...dconant — 12:38 PM
Philco Model 16 wiring question
Thanks Morzh. So it appears I did wire it incorrectly and I have to switch the wires between pins 2 and 4.bobclausen — 09:24 AM
Philco 46-1209 strange behavior
No, it's not a problem, just during certain condition it could show up. Yes, an internal tube short could do that too. ...morzh — 09:13 AM

[-]
Who's Online
There are currently 670 online users. [Complete List]
» 1 Member(s) | 669 Guest(s)
Avatar

>