Late 50s to 60s vintage US two wire "safety" power cords. - Page 1
Forum section: electronics / repair

author: CatalinaWOW
author_rank: Super Contributor
timestamp: October 17, 2023, 09:17:24 pm
content: I've got some old AA5 radios (late 1950s to 1960s vintage) which use a "safety" two wire power cord. It is snapped into the rear cover at the factory, and thus forces removal of the power when accessing the chassis to check tubes or do other repair. It was one of the mitigations for the old hot chassis design.I am searching for replacement cords, but my google foo hasn't been up to the task. The closest I have come up with is the following:https://www.ebay.com/itm/323651338305In addition to the outrageous price, and the sold out condition this does not have the locking feature which ties the cord to the back cover. The feature was just a catch molded into the top and bottom of the plug which let it be fairly easily inserted at the factory and relatively difficult to remove. Does anyone have suggestions for search terms which might lead to these cords, or a suggestion for a source?Thanks

author: floobydust
author_rank: Super Contributor
timestamp: October 17, 2023, 09:21:23 pm
content: Back in the day we called them "cheater cords", were mainly used on TV's.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 17, 2023, 09:24:45 pm
content: do you mean the same model as the link but have an metal insert clip to lock it on the casingit's been a very long time since i saw this modelthey where used for wood enclosures

author: CatalinaWOW
author_rank: Super Contributor
timestamp: October 17, 2023, 09:57:07 pm
content: Cheater cords was the link that got me to the ebay listing I reference.The linked cord would physically fit. While I have seen the metal clip version, I believe the radios I am restoring had a triangular catch molded into the plastic surrounding the contacts. I actually have one such cord, salvaged from somewhere years ago, but want to get some to dedicate to these radios which will probably be sold at some time. And yes, it has probably been forty or more years since I have seen one in the wild. They weren't intended to be a user serviceable part so wouldn't have shown up in hardware stores and the like.I can buy cords that work electrically for a couple of bucks apiece. They are mechanically not stable so I didn't think I could use them in anything I would pass on. But the metal clip reminder may give me an idea about how to use them. Thank you.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: October 17, 2023, 10:05:36 pm
content: A little thought reminded me why we called them cheater cords. The OEM cords were fastened to the back cover or case such that it was difficult or impossible to separate the cord without damaging the case, cord or both. But servicemen and other people who wanted to operate the equipment with the back off cheated and used a cord which was salvaged from a non-repairable set. Hence a "cheater cord".I am looking to keep the uninitiated safe so want a cord that becomes semi-permanently attached to the back panel.

author: Stray Electron
author_rank: Super Contributor
timestamp: October 17, 2023, 10:37:49 pm
content: Quote from: CatalinaWOW on October 17, 2023, 10:05:36 pmExactly right. The back panel of most TVs and the old many tube type radios was made of a cheap fiber board and they had a rectangular cutout in them for the connector end of the cord to fit in and a sliding metal clip on the inside that locked the connector in place. When you took the back off of the set, the cord was automatically unplugged from the set. They did sell cheater cords but everyone that I know simply salvaged one from a discarded set. If you were caught somewhere without a loose cord, you could slide the metal latch off of the back of the set and remove the cord and then use it to plug in the set without the back on it. It didn't take much effort to use the cord without the back on the set but apparently it was just enough so that consumers couldn't sue the manufacturer for selling a dangerous product.Some of the later plastic cased radios did use a cord that had a tapered catch in it that would lock into the plastic and thy were more difficult to removed but all of the TVs that I've seen used a fiberboard back panel and that material was too weak to securely hold a cord with the tapered catch so all of the TVs that I've seen used a sliding metal latch to slide into a groove on the connector.Today I can't imagine anyone needing or wanting one bad enough to pay $25 for one on E-Greed!

author: PwrElectronics
author_rank: Regular Contributor
timestamp: October 18, 2023, 03:08:43 pm
content: I don't have a source but here is what the type with the metal clip on the back looks like installed. The clip is not pushed on fully as I earlier removed it to power up the radio it on w/back off for troubleshooting.This is a mid '60s GE clock radio that is on my to-do list. The clock runs but tubes are not lighting up so there is a open someplace as this is a series filament set I think (no pwr xformer).

author: CatalinaWOW
author_rank: Super Contributor
timestamp: October 18, 2023, 06:32:06 pm
content: A little more googling found other sources for the cord referenced in my first post, in stock, at a better but still high price.But the comment by coromonadalix set me on the road to the solution I am going with. The cords shown in the first picture (sorry about the quality) are available for a couple of bucks and fit the pin spacing. That plus the adapter shown in the second picture, printed in TPU, and some gorilla glue or epoxy will give me what I am looking for. It turned out the the pins are a bit off center in the aperture, which is unusual I think. A am attaching the FreeCAD model of the adapter so that others can modify it to fit their needs.Finally, and just for fun, a picture of the radio in question. While I haven't got an exact date for it, it is one of the last in the AA5 line, uses miniature tubes and a PWB for connections. Wasn't new enough for the electrolytic power supply capacitor to be good, but dug the innards out and replaced them with modern units that fit easily in the old case. Looks original. Now working reasonably well, but still need to align the IFs.Thanks again for the help and suggestions.

author: soldar
author_rank: Super Contributor
timestamp: October 18, 2023, 09:46:52 pm
content: Quote from: CatalinaWOW on October 18, 2023, 06:32:06 pmThe "figure 8" connector is used in modern devices (I have laptops that use it) and might fit the older, rectangular connectors but I would not consider them a "true" replacement.I am old enough that the first radio receivers I built were of the 5 tube type. I remember listening in SW to all the stations from the communist countries where they talked about how superior their system was, how happy everybody was, etc. It was a laugh. And all this with a lot of static, whistling, etc. It was all very exciting for a 14 year old.My mother had a "baby" radio by her bed with live chassis and it was supposed to be well isolated on the outside but the tuning and volume controls, which were plastic, had set screws which were not deep enough and if you touched them you could get a nice shock. At that tender age I did not know the trick of reversing the plug.The rectangular plugs, I suppose were standardized but I had some that had the holes a bit to close and the solution was to slice them in the center with a knife so the holes could separate a bit more.I think I probably still have quite a few in some crate in all the piles of junk I have accumulated over the decades.