Suggestion on decade resistor? - Page 1
Forum section: electronics / general

author: branadic
author_rank: Super Contributor
timestamp: July 14, 2018, 07:49:46 pm
content: Currently I'm interested in buying a 7 dial decade resistor. Several offers on ebay are available, but I would like some feedback:I wonder if someone here has aBeckman 71-DRK 7 Precision Decade Resistor boxand can say something about it? Are there any teardown pictures available? What are the specifications?Pictures and datasheet of aGeneral Radio Type 1434-G - Decade Resistorscan be found on internet, but what is such a unit worth and what to look after?-branadic-

author: branadic
author_rank: Super Contributor
timestamp: July 22, 2018, 06:47:44 pm
content: Decided for the General Radio Type 1434-G and made an offer to the seller that was accepted. So now I need to wait for the unit to arrive.-branadic-

author: Henrik_V
author_rank: Regular Contributor
timestamp: July 22, 2018, 07:56:24 pm
content: And it seems to be a genuine GR !

author: gbaddeley
author_rank: Regular Contributor
timestamp: July 23, 2018, 11:53:02 am
content: 0.02%, nice. The GR looks much better than the crusty Beckman.

author: branadic
author_rank: Super Contributor
timestamp: July 23, 2018, 05:13:48 pm
content: QuoteLook is one thing, but what matters are the intrinsic values. I have hoped to get some info on the Beckman to learn about it's accuracy and T.C.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: July 31, 2018, 09:49:51 am
content: My decade resistor box arrived today, much earlier than expected. It's in reasonable condition by the looks of it, a few new switch caps would be fine. Do IET sale them as spare parts?Need to test it first at home and afterward on our 3458A. First of all, time to brake the cal stickers on it and check if everything inside looks okay.If you guys need one unit, there are two left. Just place an offer to the sellerEDIT: No overload visible inside and a first sanity check on my Prema 5000 shows very good results, that have to be verified on 3458A. Cleaned the unit, removed old sticker and dirt on the panel.-branadic-

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: August 01, 2018, 12:25:51 am
content: Those newer ones are nice, but the switches aren't as massive as the old ones. AFAIK, they never made a 7 decade unit in the old style. I just use a couple 1432 series, with the range suited to the purpose at hand. Don't forget the less pretty Shallcross resistance boxes. IMO, probably as good as the GR, and a handier footprint on the bench. An interesting GR one is the 670-F compensated box for AC use. Introduced in the March 1934 issue of the Experimenter, it also switches small inductors to keep a constant inductance value for every setting. At the very end they show a compensated slide wire that's pretty clever.https://www.ietlabs.com/pdf/GR_Experimenters/1965/GenRad_Experimenter_Oct_1965.pdfhttps://www.ietlabs.com/pdf/GR_Experimenters/1934/GenRad_Experimenter_March_1934.pdf

author: branadic
author_rank: Super Contributor
timestamp: August 03, 2018, 10:32:48 pm
content: Measured decade resistor box on 3458A today and it seems to be well within spec. So if one of you is searching for a working unit, there are still two units left.-branadic-

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: August 03, 2018, 11:11:09 pm
content: FWIW, I've never seen a GR resistance box out of spec. Even some mildly toasted units (discolored from overload) have measured OK. I've got quite a few old ones, but none of the newer horizontal style due to the price premium they seem to carry.

author: mmagin
author_rank: Frequent Contributor
timestamp: August 03, 2018, 11:47:05 pm
content: I've got one of the old black finish 5 decade GR 1432 boxes. Aside from needing some cleaning, it's worked just as spec.

author: BradC
author_rank: Super Contributor
timestamp: August 04, 2018, 08:35:17 am
content: Quote from: branadic on August 03, 2018, 10:32:48 pm...One unit left.

author: Dwaine
author_rank: Frequent Contributor
timestamp: August 14, 2018, 04:07:53 pm
content: I bought one too. Really good condition.

author: BradC
author_rank: Super Contributor
timestamp: August 15, 2018, 07:08:27 am
content: Quote from: BradC on August 04, 2018, 08:35:17 amArrived yesterday. Meets specification within my limited ability to test directly.Hooked it up today as the variable trimming element in a Wheatstone bridge. What a pleasure to use.

author: branadic
author_rank: Super Contributor
timestamp: August 15, 2018, 06:02:01 pm
content: Nice, 3 out of 4 are in this community-branadic-

author: DC1MC
author_rank: Super Contributor
timestamp: August 15, 2018, 07:58:48 pm
content: Is there any left ?DC1MC

author: doktor pyta
author_rank: Frequent Contributor
timestamp: August 16, 2018, 09:42:13 am
content: You may consider this (from DE):https://www.ebay.de/itm/Doppelte-Tettex-Widerstandsdekade-Messgerat-Resistance-Decade-Typ-1122/401570133849?hash=item5d7f71f759:g:xMwAAOSw9fpbUbOyTettex is also known for it's quality products.

author: branadic
author_rank: Super Contributor
timestamp: August 16, 2018, 01:34:24 pm
content: Quote from: DC1MC on August 15, 2018, 07:58:48 pmQuoteSimply click the link-branadic-

author: cat87
author_rank: Regular Contributor
timestamp: August 17, 2018, 03:25:37 pm
content: QuoteMake that 4 out of 4Will do the mandatory posting of measurements when i get it. September-ish, if I'm to believe eBay's estimation

author: cat87
author_rank: Regular Contributor
timestamp: August 29, 2018, 03:21:14 pm
content: Well well, guess Christmas sometimes does come early. The GenRad decade resistor just arrived today. Checked all the decades and with my 3478A, all I can tell is that the unit is well within spec. The higher ranges approach 0.02% but the lower ones are around 0.015%All in all, not bad. I have a Keithley 199 that's I might calibrate with the GenRad and a Fluke 8505A that's way out of whack on the Ohms ranges. Might give that a try also. It'll be some fun couple of days