Author Topic: Wiring a 302 top on a 304 base  (Read 1068 times)

Offline f18shack

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Wiring a 302 top on a 304 base
« on: October 13, 2014, 01:20:30 PM »
Hello all, this is my first post. I came here originally for help restoring a 302 purchased at a local antique fair.  The phone worked, but it sometimes misdialed and the ringer seemed weak. Based on many recommendations here, I sent the dial to Steve Hilsz in Arizona and he did a great job. 

When it came time to reassemble the phone, the photos I'd taken of the wiring before teardown were different from every diagram I found online.  Nothing matched, and only two of the four leads in the the hook switch had wires connected to them.  It seemed like a good idea to do more research and get it wired right!

Based on info from this forum,  this phone has a 304 base, with a 101B coil with "M" and "RR" terminals, a B2A four wire ringer, and a large size terminal block that has L1 and L2 added to the normal K and GND terminals.  The top of the phone looks like a normal 302 (with a 5H dial and four wire hook switch).  Several posts here and elsewhere indicate that the 304 had a six lead hook switch.   

I first tried wiring the base according to this forum's diagram for a 304 with a four wire ringer, but found the phone rang but wouldn't dial out, (I'm guessing because the hook switch is 302 style and doesn't have six leads?).  After some trial and error, I came up with a solution that was a combination of things posted for 302's and 304's. I attached a diagram and wanted to share it in case anybody else runs into the same situation. 

Does anyone see anything blatantly wrong, or that might damage the phone?  It works great and the ringer is strong. 

Thanks for all the help. 

Rob


« Last Edit: October 13, 2014, 01:22:30 PM by f18shack »

unbeldi

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Re: Wiring a 302 top on a 304 base
« Reply #1 on: October 13, 2014, 01:31:59 PM »
The extra two springs, or the extra switch, in the hookswitch of a 304 disconnect the L2 line side from the telephone when the set is wired for individual bridged-ringing service according to BSP C38.555 i2 (1958), as you would want it today.

So, when you don't have that extra switch, then you simply connect the line wire (normally on L2) and the yellow wire from the ringer capacitor to RR, bypassing that switch that doesn't exist.

You can find a diagram here:  http://www.classicrotaryphones.com/forum/index.php?topic=5720.msg126771#msg126771

 
« Last Edit: October 13, 2014, 04:09:58 PM by unbeldi »

Offline poplar1

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Re: Wiring a 302 top on a 304 base
« Reply #2 on: October 13, 2014, 01:32:45 PM »
Rob, everything looks good from here. The RR terminal on the 101B is equivalent to the L1 terminal on the 101A induction coil. However, the M is not equivalent to the L2-Y terminal on a 101A.  L2-Y is not connected to anything inside the 101A induction coil, it's just a connecting point. So you can choose any unused terminal on the block as a connecting point, as you have done.
"C'est pas une restauration, c'est une rénovation."--François Martin.

Offline f18shack

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Re: Wiring a 302 top on a 304 base
« Reply #3 on: October 13, 2014, 02:23:37 PM »
Rob, everything looks good from here. The RR terminal on the 101B is equivalent to the L1 terminal on the 101A induction coil. However, the M is not equivalent to the L2-Y terminal on a 101A.  L2-Y is not connected to anything inside the 101A induction coil, it's just a connecting point. So you can choose any unused terminal on the block as a connecting point, as you have done.

Thanks, that's good to hear.