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

High Plate Voltage on IF tube 39-116
#3

(11-14-2014, 08:49 PM)Ron Ramirez Wrote:  Hi Jeff

A look at the schematic indicates 160 volts is incorrect - it should be 260 volts. Notice on the schematic, the plate of the IF tube connects to the screen grids of the 42 output tubes through the primary of the 2nd IF transformer.

Try injecting a 455 kc signal through the control grid of the IF tube. If you get nothing, then use a 0.1 uF cap in series with your signal generator to block the DC from going into your generator, and inject 455 kc into the plate terminal of the IF tube. If you still have nothing, then there must be a problem with your 2nd IF transformer.

Don't forget to check continuity of the 2nd IF secondary (between the 51K resistor and the green wire).

Yes see it now Ron, the red wire out of the 2nd IF to the 42 tubes. Injected the 455 kc signal in in both methods as you had indicated....very distant faint crackling. I will pull the 2nd IF transformer and see what I have. I did get readings in tolerance (primary and secondary resistance) but something may have shifted in reattaching it.

Thank you Ron.


Jeff


Messages In This Thread
RE: High Plate Voltage on IF tube 39-116 - by jeffgniffke - 11-14-2014, 09:15 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Need to purchase some accessories for restoration of my Old Philco Radio
Hi Paulo, Welcome to the Philco Phorum. I can see why you want to find good reproduction parts. That is a bea...MrFixr55 — 11:10 PM
HiFi (Chifi) tube amp build - but my own design.
Tim, I have some bakelite sockets in my work shop that I can dig up. I believe quite a few are NOS. I will take photo...RodB — 10:03 PM
Philco 610B oscillator wiring
> The cathode as noted is wired directly to the ground side of the heater filament for that tube, not to the #17 and ...Radioroslyn — 08:12 PM
HiFi (Chifi) tube amp build - but my own design.
Tim; I noticed your post a little late, but I would take one of the junk sockets and try to break a chunk out of it wi...Arran — 08:07 PM
Need to purchase some accessories for restoration of my Old Philco Radio
Here is a list of resources found in our online library that you might find useful. Mike's Gobs of Knobs email addres...klondike98 — 01:46 PM
First Radio restoration
Hi Tubeman, Welcome to the Philco Phorum.  Phamily Phriendly Pfun with Phine Pholks Phull of Philco Phacts. (See a p...MrFixr55 — 12:33 PM
First Radio restoration
You could post in the WANTED ADs section here on the Phorum and see if anyone has an RF generator that they want to sell...klondike98 — 11:55 AM
Zenith H725
Good ideas, thank you Arrange and Rich. I have the adhesive aluminum foil already and can try that immediately. More ...EdHolland — 10:18 AM
Graphics for majestic 1050 dial glass.
Murf; I found this thread on the ARF, the first photo has a pretty good view of the dial glass. Regards ArranArran — 01:12 AM
Zenith H725
hello Ed, how about that speacial tape used for ducting it's like foil or how about thin piece of aluminum roof flash...radiorich — 12:19 AM

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

>