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

Philco 90 grid voltage and RF choke
#1

I am also working on a early pp 45 Philco model 90 and thankfully the filament voltages are all normal.  

My issue is that all the grid voltages are low, some negative.  The set plays very softly and I can tune in stations.  I have completed a re-cap and the resistors and coils all check out.  The plate voltages are ok.  I will be going through the set looking at each grid connection but I was wondering if anyone had a similar issue?

The only thing I found so far is that the RF choke (labeled 52 on schematic) between the 24 and 27 tubes is missing.  I assume the radio played without it so is it necessary and could it drag down all the grid voltages?

Thanks for your help,

David


Dallas Texas


Attached Files
.pdf 90a.pdf Size: 642.5 KB  Downloads: 138


Messages In This Thread
Philco 90 grid voltage and RF choke - by Davidra - 04-10-2016, 02:26 PM



Users browsing this thread: 3 Guest(s)
[-]
Recent Posts
6TPZ and 5TPO Radio Help
1 - 0v - correct 2 - 0v - correct 3 - 0v - --------------------- both 3 and 4 should be the same. Check L2 for being ope...morzh — 05:15 PM
B&K 1077B no video
I'm going to get back into it tonight. but I disconnected the 2 main resistors off this supply going to different parts ...TV MAN — 04:04 PM
6TPZ and 5TPO Radio Help
Sorry. The test points are as follows: 1 - 0v 2 - 0v 3 - 0v 4 - 12v 5 - 0v 6 - 11.9v 7 - 12v 8 - 12v 9 - 12v...R3Sons — 02:09 PM
6TPZ and 5TPO Radio Help
OK, so 18 and 19 as they should be. What is "everything else?" Try to be more specific in your descriptions:...morzh — 12:44 PM
6TPZ and 5TPO Radio Help
Yeah, I'm still on 5TPO. Sorry, my bad, points 1 and 2 should be points 18 and 19 (easy mistake  :think: )  X7 is shown ...R3Sons — 11:42 AM
Philco 40-120C Filament Wiring
Hi folks, I'm in the process of restoring a Philco 40-120C and I'm finding the wiring to be a bit puzzling. According to...bluecap — 11:28 AM
462ron
Hi Levi, here’s just a thought. Most radios run the oscillator higher than the dial setting. Say you set your radio to 1...462ron — 10:10 AM
1930s Stewart-Warner Tombstone Radio need help identifying model number
Another Update: I found a couple of damaged coils inside this radio that might have something to do with why this radio ...captainclock1988 — 10:51 PM
6TPZ and 5TPO Radio Help
If you are still on 5TPO, you lost me there. What X7? What Points 1 and 2?morzh — 08:37 PM
6TPZ and 5TPO Radio Help
Quick progress report: X7 is broken. Only one leg soldered, the other missing and the diode is cracked. I've replaced...R3Sons — 05:05 PM

[-]
Who's Online
There are currently no members online.

>