Hi all. First time here. I hope someone can help me identify my connectors. I am repairing an 1949 Motorola cabinet radio and I’m trying to make an extension cord of sorts for the speaker and phono connectors so I can work on the chassis without having to install it every time I need to test it. That is not an easy process. The problem is, I can’t find modern day equivalents because I don’t know what they are called. Someone on a different forum suggested the males are called “connector pins” and referenced part 1224 from Keystone. That looks like it would work for the male side but I don’t know what the female side would be called. I chatted with someone at Keystone but he wasn’t able to help me. I’m attaching photos of the existing connectors, or at least I hope I am, in the hopes that someone here can help me identify them by name so I might be able to search for them. I need the name of the male and female connectors. Thank you in advance!
This is an example of what I am trying to make. The male end is adequate but the female connector pictured is too narrow.
Welcome to the Technical Forum. We sell the Keystone part number on this link: 1224 Keystone Electronics | Connectors, Interconnects | DigiKey
I would say for the other side , you would need something like ED5034-ND on this link: 0390-0-15-01-08-27-10-0 Mill-Max Manufacturing Corp. | Connectors, Interconnects | DigiKey
Thank you!!! I will give both a try.
Welcome to the DigiKey Forum.
Some of the connectors look like tube sockets. Rather than reinvent the wheel the designers from the 1930 and 1940s used existing tooling components. The most convenient connection was often the tube socket.
If you have a collection of old (not worthy of restoration) radio sets, you may already have what you need. The male pins may be salvaged from an old tube. The female by disassembling the chassis.
Thanks. That’s what someone on the other forum suggested too. Unfortunately, I don’t have anything lying around that fits the bill.
P.S. Watch out for those speaker connections as they often have high voltage.
Way back to the 1930s and 40s, permanent magnets were expensive. It was often easier and cost effective to use an electromagnet on the speaker assembly. In yet another money saving feature, the speaker coil served double duty as speaker magnet and choke (inductor) for the DC power supply.
Consequently, the main 300 VDC or higher supply for the radio set is sent to and then returns back to the radio.
This is a nasty and deadly safety trap for newcomers and certainly something to watch out for as you build a speaker extension cord.
The 300 VDC supply with fully charged capacitors and inductors is nothing to mess with…
That’s excellent advice. I wasn’t aware of this. Thank you!
Sometimes it’s even worse, as all 4 wires operate at high voltage.
For example, consider the Zenith model 860 radio set that sits in my office corner. It has 4 wires connecting the speaker to the chassis. On the schematic connections 1 and 2 are the high voltage field coil. Connections 3 and 4 are the high voltage output transformer. Here, the output transformer can be seen at the top of the speaker.
Thanks. It looks like my speaker will have between 220 - 320 VAC on its wires when plugged in. Scary stuff. Thanks for pointing this out.