WTD [UK] Old style 'oval' HP AC cord / mains lead - Page 1
Forum section: electronics / general

author: andymcc
author_rank: Newbie
timestamp: April 12, 2022, 03:24:59 pm
content: A rare 3734A nixie counter is on its way to me, but without its special vintage AC cord..Would anyone in GB have a spare they might part with for a suitable amount ?TIAAndy

author: kbrill
author_rank: Contributor
timestamp: April 12, 2022, 05:48:49 pm
content: Be very careful what you purchase last batch ( 25pieces ) I purchased from a major distributor were new , prime brand however very old stock and aging badly . This was 10 years or more ago .

author: PaulAm
author_rank: Frequent Contributor
timestamp: April 12, 2022, 07:01:45 pm
content: These things are getting very hard to find and they don't appear to be currently manufactured. When I see them, they're > $20USD ea.There is a thingiverse 3d model for printing a compatible plug that works pretty well. In many cases you can fit a standard IEC socket and just use the commodity cords.

author: alm
author_rank: Super Contributor
timestamp: April 12, 2022, 07:16:35 pm
content: You might have more luck in the US. The cables are more common there. Use an adapter to convert the plug from US to UK style. I've heard that the oval sockets are only rated for 110V, but if distributors in the UK were selling these cords with UK plugs, that must not have been true at that time.

author: factory
author_rank: Super Contributor
timestamp: April 12, 2022, 07:54:58 pm
content: Quite a few of us on here have a 3734A counter, they were made in the UK and were updated from 2MHz to 5MHz during the production run.https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/93325/They are usually only found with equipment in the UK, keep buying more & you might end up with one.Or buy one from the US, Belden/Volex (17952 & 17280) & Alpha (543 & 544) made the power cords and they were used on lots of US made equipment prior to IEC becoming standard. Some information from the TEA thread below.Quote from: factory on May 05, 2019, 01:09:25 pm

author: TimFox
author_rank: Super Contributor
timestamp: April 12, 2022, 08:31:37 pm
content: One reason why these connectors are hard to find is some very nasty accidents that occurred in medical facilities where banana plugs were mated with the female connector on a line cord.One case is mentioned at the very end of the page in this link:https://books.google.com/books?id=6FnADEZu3tUC&pg=PA26352&lpg=PA26352&dq=medical+accident+with+EKG+leads+and+power+cords&source=bl&ots=7ZqYfqLXru&sig=ACfU3U1eUj0qNEAx1DEZIpf1ITiL3OXncw&hl=en&sa=X&ved=2ahUKEwjfpJzpro_3AhUUhYkEHXiSDhEQ6AF6BAgtEAM#v=onepage&q=medical%20accident%20with%20EKG%20leads%20and%20power%20cords&f=false

author: factory
author_rank: Super Contributor
timestamp: April 12, 2022, 09:31:54 pm
content: HP stopped using them around 1970, but cords were still made into the 2000s.Nothing to stop people found getting shocked by an IEC lead, or wall outlet/socket if they are determined enough. I did note CPC sell a molded UK plug cord/lead, to bare wire ends at the other end.David

author: TimFox
author_rank: Super Contributor
timestamp: April 12, 2022, 09:37:05 pm
content: The unfortunate medical accidents were facilitated by the circular female sockets in the older connector, which we sometimes called a "business-machine" connector due to its use on adding machines.Fools are sufficiently ingenious that we need not make it easier for them to commit foolish acts.

author: dl6lr
author_rank: Frequent Contributor
timestamp: April 12, 2022, 09:55:07 pm
content: Quote from: PaulAm on April 12, 2022, 07:01:45 pmAn IEC-C6-plug is often the easiest to use without metal work, C14 does not fit in the cutout for the oval plug. You do need an adapter board to match the different fastener distance.

author: woodchips
author_rank: Frequent Contributor
timestamp: April 13, 2022, 05:38:44 pm
content: I have one that you can have free of charge.There are conditions, that you give to the Salvation Army a donation, at least the postage cost plus what ever you feel the lead is worth.This lead, like the others, is now very old and the plastic dries out where it is sharply bent at the end of the socket. This one looks ok but no longer have a megger to test.If interested then please pm me your address so I can post it in the UK.

author: CJay
author_rank: Super Contributor
timestamp: April 13, 2022, 08:11:43 pm
content: Pretty sure I've seen similar on sewing machines.

author: andymcc
author_rank: Newbie
timestamp: April 14, 2022, 07:40:50 am
content: Oh, I'm a bit overwhelmed by the response ! What a community ! Thanks folks so much.The old HP 3734A landed yesterday and it's in pretty good shape for 60 years old. There's no sign of anyone ever being in there before, all boards present, and no internal damage apparent. It will just need a very careful check-over before bringing it all back up, a bit at a time. I'm going to try re-forming then checking all the electrolytics individually to see how many I can save.I had been thinking of how to re-create/improvise a safe alternative AC cord, so all these suggestions and info are much appreciated.'Woodchips' I will send a PM.ATB, Andy(PS. Soz for the big linked pics, attachments aren't working for me..)

author: factory
author_rank: Super Contributor
timestamp: April 14, 2022, 07:07:25 pm
content: The picture size is fine, getting the forum pictures inline with the text is tricky, long running forum problem, but does work with the IMG code & the correct link.Your counter can't be any older then 55 years, adding 60 to the serial number prefix "720" gives 1967, week 20 as the last design revision prior to your counter being made, it could be several years newer for TE that had very few design changes. The letter is the factory site code, "U" was the South Queensferry site in Scotland, now replaced with another crappy housing estate.Something I immediately noticed is that the frequency standard/reference switch on the back is set for "Ext", the counter will not work unless changed back to "Int", or an external reference is connected to the input on the back, this sort of thing can catch people out, even worse if they used a little toggle switch instead.And no boards are missing, must mean you have the 10 second option board (A16) already fitted in the slide out decade divider assembly.David

author: Gyro
author_rank: Super Contributor
timestamp: April 14, 2022, 07:47:37 pm
content: Quote from: andymcc on April 14, 2022, 07:40:50 amPicture physical dimensions is rarely a problem. It's the multi Megabyte images that some people upload for no good reason that tend to get peoples' backs up (particularly those on low bandwidths). A large image compressed to a few hundred k (and thumbnailed where inline isn't essential) is perfectly fine for pretty much everyone.

author: andymcc
author_rank: Newbie
timestamp: April 14, 2022, 07:51:20 pm
content: Thanks David, for all that. I'm sure I'd have picked up that switch, I am also working on a GPSDO.. I've not yet removed that plug-in assembly but just now looking inside I can see theres actually an unpopulated slot, which presumably is where A16 goes. Maybe over the weekend I'll do a full strip/clean/inventory, and start from there. I should do a proper 'resto thread' really not clog up the For Sale section with chit chat !

author: CJay
author_rank: Super Contributor
timestamp: April 15, 2022, 08:20:21 am
content: In the US but:https://www.storproperty.com/archive/Hp-Hewlet-Packard-Celestron-Wurlitzer-Ph-163-Vintage-3-Prong-Oval-Ac-Power-Cord/rjt073825530053.html

author: factory
author_rank: Super Contributor
timestamp: April 15, 2022, 11:32:10 am
content: Is that a real website? as it seems to be a copy of an expired ebay listing from this seller (which has none listed anymore);https://www.ebay.com/itm/185335304750, they did have the grey cords too.David