Author Topic: 2/51 501 w/425A network and 426A tube  (Read 707 times)

Offline zaphod01

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2/51 501 w/425A network and 426A tube
« on: May 30, 2016, 07:31:09 PM »
Phone had no dial tone. I reconfigured per Dan/Panther's wiring diagram but still no dial tone in either polarity configuration. Bypassed the equalizer and it made no difference. I suspect a dead tube. Next obvious trouble-shoot would be to bypass the 426A.

Can someone direct me to a wiring diagram for a 425A network and a 2-wire ringer?
"Things are never so bad they can't be made worse." - Humphrey Bogart

Offline rdelius

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Re: 2/51 501 w/425A network and 426A tube
« Reply #1 on: May 30, 2016, 07:35:23 PM »
The tube is in the ringing circuit. Will not affect dial tone

Offline zaphod01

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Re: 2/51 501 w/425A network and 426A tube
« Reply #2 on: May 30, 2016, 07:41:05 PM »
I guess I'm just lost on the basic connections for a 425A and a 2-wire ringer. I need to start at the beginning.
"Things are never so bad they can't be made worse." - Humphrey Bogart

Offline AL_as_needed

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Re: 2/51 501 w/425A network and 426A tube
« Reply #3 on: May 30, 2016, 09:43:31 PM »
Without the tube, a 501 can be wired as a standard 500 set. If you do have the tube and want to have it as part of the circuit there is a diagram somewhere on here I have used in my restoration of a 501 not long ago. I'll see if I can find the posts.
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Offline AL_as_needed

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Re: 2/51 501 w/425A network and 426A tube
« Reply #4 on: May 30, 2016, 09:57:06 PM »
Here is a picture of a 501 with the tube installed, I think I got it off picasaweb.google.com if I recall correctly.
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Offline poplar1

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Re: 2/51 501 w/425A network and 426A tube
« Reply #5 on: May 30, 2016, 11:15:42 PM »
I guess I'm just lost on the basic connections for a 425A and a 2-wire ringer. I need to start at the beginning.

Is that a C3A ringer? I don't think I've ever seen one.
Here are the original diagrams for 500B and 501B: Figures 1 and 2. (From TCI library).

http://www.telephonecollectors.info/index.php/document-repository/doc_details/3200-852-220-101-i1-500-series-transmission-a-b-j-k-s
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Offline zaphod01

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Re: 2/51 501 w/425A network and 426A tube
« Reply #6 on: May 31, 2016, 06:06:35 AM »
2-wire ringer is unmarked other than the 2/51 date (photo). Thanks for the link to the schematic. I'll have another go at it. I just realized I have a 3/51 500T (next in line) sitting right next to the 2/51 501. I assume it also has a 425A network. Duh...
"Things are never so bad they can't be made worse." - Humphrey Bogart

Offline poplar1

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Re: 2/51 501 w/425A network and 426A tube
« Reply #7 on: May 31, 2016, 11:27:13 AM »
The 500T does not have an equalizer, unlike your 501 or 501B (which do you have?).
The ringer is also different in a 500T, since both the C2A and C4A have 4 wires.
When a tube is in the ringer circuit, the capacitor (A and K) is not used, as it would prevent the ringer from operating. Notice that in a 501 or 501B with 425A network, both slate leads from the line switch (hookswitch) are terminated on the same terminal (A), and that K is vacant.

In the 500B, rather than have the spade-tipped gray line switch wire connected to A, it is connected to L2. This completes the ringing circuit (L2<---------A--------/(-----------K-<----------------Ringer------------->G. (The other gray line switch wire is soldered.)
                               
"C'est pas une restauration, c'est une rénovation."--François Martin.

Offline JorgeAmely

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Re: 2/51 501 w/425A network and 426A tube
« Reply #8 on: May 31, 2016, 11:46:31 AM »
You can see the entire photo collection for the album I made a while back. Included are some details as to how to wire a phone with a tube. The tube is polarity sensitive. Once wired in, the phone will ring only when biased correctly.

https://picasaweb.google.com/Amelyenator/WesternElectric501PhoneWithA426ATube  ( deal link 1-6-18 )

     Western Electric 501 Phone with a 426A Tube

« Last Edit: January 06, 2018, 12:29:26 PM by TelePlay »
Jorge