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: 4 Guest(s)
[-]
Recent Posts
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
6TPZ and 5TPO Radio Help
Oh...and you have electrolytic caps there. All need to go and be replaced.morzh — 04:36 PM
6TPZ and 5TPO Radio Help
Thanks, will do.R3Sons — 01:25 PM
1930s Stewart-Warner Tombstone Radio need help identifying model number
UPDATE: I was able to pick up a signal generator on the cheap (amazingly enough) on feebay and I did an IF alignment fol...captainclock1988 — 09:53 AM
Philco 91 Schematic
Hi Rod, The resistor connects to pin 4 and the ungrounded side of block 9. From pin 9 of the RF tube to one side of ...dconant — 09:34 AM
Just got a 49-1613 need to know...everything!
I just found your post. I have this exact same model, and have had it since 1985 when I was 15 years old! I performed a ...MuzzcoVW — 09:11 AM
B&K 1077B no video
Hello Tim, I would if it's a leaky Capacitor So are all 3 of those B- voltages low then ? Sincerely Richardradiorich — 01:55 AM
B&K 1077B no video
I found a schematic and think I have the problem traced down to the minus power supply. I have very low voltages that go...TV MAN — 12:41 AM
RCA 15X
I'd try replacing the bulb first and if that doesn't do it, then change the 35Z5 and see if the problem goes away.NostalgiaRadioTime — 12:28 AM
B&K 1077B no video
Hello Tim, I have that exact unit in my shop too plus a Sencore unit there are times I like one or other !!. Sincerely...radiorich — 11:07 PM

[-]
Who's Online
There are currently 10193 online users. [Complete List]
» 3 Member(s) | 10190 Guest(s)
AvatarAvatarAvatar

>