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

RCA 56X2 Output Transformer
#9

On this radio there isn't a cap from plate to ground. There is a cap (.02 mf, 700 volt) across the primary of the output transformer, including the tap that is used as a B+ choke. I used two .04 mf caps in series to make the higher voltage than the 630 volt caps I am using.

There are variants of this radio that do have a cap from plate to ground, but not this one. There also is not a cathode bypass cap, just a self-bias resistor.

As I understand from Mondial and the tube data sheets he linked to, I need a transformer with 2500 ohms primary impedance. Now, per the schematic the primary voltage is 125 V, so plate current is a tad under 100 mA. So I need a transformer that will handle 100 mA on the primary?

The total B+ current for this radio is about 20 mA when it is working properly. With the primary open as it is now, it is about double that.

What about the secondary? What impedance should I look for?

Is DC resistance irrelevant?

I'll measure the cathode current again with another tube, but I probably won't be able to do it until tomorrow evening.

Thanks to everyone for their suggestions.

John Honeycutt


Messages In This Thread
RCA 56X2 Output Transformer - by Raleigh - 04-12-2013, 01:14 PM
RE: RCA 56X2 Output Transformer - by BrendaAnnD - 04-12-2013, 03:49 PM
RE: RCA 56X2 Output Transformer - by Raleigh - 04-12-2013, 05:17 PM
RE: RCA 56X2 Output Transformer - by BrendaAnnD - 04-12-2013, 07:55 PM
RE: RCA 56X2 Output Transformer - by Raleigh - 04-12-2013, 10:30 PM
RE: RCA 56X2 Output Transformer - by Mondial - 04-12-2013, 11:14 PM
RE: RCA 56X2 Output Transformer - by BrendaAnnD - 04-13-2013, 01:19 AM
RE: RCA 56X2 Output Transformer - by 7estatdef - 04-13-2013, 03:22 PM
RE: RCA 56X2 Output Transformer - by Raleigh - 04-13-2013, 05:56 PM
RE: RCA 56X2 Output Transformer - by Arran - 04-14-2013, 12:01 AM
RE: RCA 56X2 Output Transformer - by Mondial - 04-14-2013, 08:55 AM
RE: RCA 56X2 Output Transformer - by codefox1 - 04-14-2013, 12:13 PM
RE: RCA 56X2 Output Transformer - by Raleigh - 04-14-2013, 10:37 PM



Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
Philco model 38 code 121 not receiving signal.
Congrats on your success Stormlord. My rough guess is that since both the 15 and the 1A6 are supposed to be shielded, I...MrFixr55 — 10:04 PM
The list of my radio & TV collection!
A little light Saturday positive about our hobby in our feed... My new every Saturday video about antique radio equipme...RadioSvit — 02:12 PM
Model 70 Cabinet Trim
musar , Well if you have any more questions feel free to post away . Sincerely Richardradiorich — 08:56 PM
Model 70 Cabinet Trim
Although I have not made any cabinets or cabinet parts for a couple of years, I still have some parts left over, includi...Steve Davis — 06:26 PM
philcorepairbench.com - shadow-meter
Thanks Ron. But I can't find those articles.fenbach — 02:43 PM
Model 70 Cabinet Trim
Thank you, Gary. Before making my original post, I had clicked on "Steve Davis Cabinets" only to find that it...musar — 02:25 PM
philco predicta
Welcome to the Phorum, cgl18! I am not your resource for television repair, but lots of friendly help is available here...GarySP — 02:12 PM
Model 70 Cabinet Trim
Welcome to the Phorum, musar! You can send Steve Davis a private message (PM). The site is at the top of the Home page...GarySP — 02:09 PM
Model 70 Cabinet Trim
How do I contact him? The only contact information for him I could find when searching online was a telephone number th...musar — 10:38 AM
philco predicta
Hello, good afternoon, I would like to ask what the possible problem could be if I don't have an image on the screen. I ...cgl18 — 10:19 AM

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

>