Round-pin mains leads (old HP, etc)

Someone recently made a "somewhat OT" post to the TekScopes list offering to give away some of the old, oval power cords that HP used a long time ago. (They were spoken for with 3 hours.) I responded with the following post about these cords, and it may be helpful to those on this list as well (and not OT here!). The bottom line is that while you have to know where to look for them, they are hardly rare or expensive. Last year I did a bit of research about the oval power cord used by HP long ago and found that it is still available off the shelf; I ordered some from Mouser to verify it. The particular power cord for this type of connector used to be Belden part number 17952, and is currently made by Volex with the same number. The manufacturer web site is http://www.volex.com I checked the web site just now and it's set up differently than it was last year. This is the path to get to it now from the home page: Products, power products, standard products, select North America, detachable, then click on the X at the intersection of "special" and "plastic" on the chart. Finally, click on "spec" for the part number. Here's where it gets interesting; scroll down to the bottom of the data and you'll see this note: "This cord is made with non-standard polarization and has a caution label applied to the cord stating this fact: `This cord is for replacement only and is NOT intended for new original equipment.' See also 17280." But we want it for replacement use, and this is the one we want. Go back up the list to the spec on either version of the 17280 (the only difference in the two versions is gray vs. black), and you'll see this note: "Polarity as mandated by CSA electrical Bulletin 895B and UL817. See also 17952." (Underwriters Laboratories is a USA organization, and CSA is Canadian Standards Association.) That's the current polarity standard. The hot and neutral pins on the older cord are reversed from that. I ordered both styles of cord from Mouser (http://www.mouser.com), and sure enough, the one for the old equipment which is now considered nonstandard polarity has a warning label on it. The price has gone up a bit since then and both types are now about $10 each. I just checked the Mouser site; they have 7 of one in stock and 24 of the other, and show a factory lead time of a week. Both Allied (http://www.alliedelec.com/) and Newark (http://www.newark.com) also carry them and have them in stock. The bottom line is that while these things might be hard to find if you don't know where to look, they are not rare by any means and you don't have to pay outrageous prices for old ones. Unless, of course, you're a collector and insist on having a 40 year old power cord to go along with a 40 year old piece of equipment :-) BTW, if you come across an oval cord like this somewhere, keep in mind that it might not be what you're looking for since the hot and neutral pins can be in two different configurations depending on which part number it is (which may not be on the cord anywhere). Be sure to verify that the polarity is the proper one for whatever you plan to connect it to. (I wrote an article on this for a small amateur radio journal last year. It had additional information and several graphics. If anyone is interested I can e-mail the text and figures.)