Help identifying some (likely older) compontents. - Page 1
Forum section: electronics / beginners

author: Traceless
author_rank: Frequent Contributor
timestamp: March 28, 2024, 10:19:23 am
content: Hi everone,I have a bunch of components here where I have no clue what they are, and a few where I have a hunch what they might be but haven't found anything definitive. So first the mystery components1. The weirdest one is a potted 3-pin throughhole component (C30355A VC) with a round gray doohickey on top, below are two axial components which based on their label are resistors - however those things are *huge* and partially pretty good precision (e.g. the 3.6 KOhm is specified with 0.02% tolerance). So based on their size and weight I wonder if there is something special about those resistors.2. A throughhole component with a clear casing labled "27 F". I think it might be a kind fuse or maybe an old style diode?3. Two components which I believe to be 47kOhm Resistor networks. Problem searching for "Rehm" I primarily find welding equipment but no electronics. For the DALE one I found similar ones albeit with more pins.

author: retiredfeline
author_rank: Frequent Contributor
timestamp: March 28, 2024, 10:23:25 am
content: The last two are resistor networks, 8 and 4 respectively. They come in a variety of number of resistors, 4, 8 and 9 are quite common. The common terminal is the dot or the black edge. Easy to confirm with a multimeter.

author: Ian.M
author_rank: Super Contributor
timestamp: March 28, 2024, 10:40:27 am
content: 'ROHM' not 'Rehm', and not to be confused with Royalohm. Unfortunately they no longer do through hole resistor arrays and data for their old stuff is often hard to find.Weird item #1 is fromThomson-CSF, who among many other things made TVs and Radar equipment. I see four terminals, as the round doohickey is a seal to keep the potting compound in when it was poured. The top cap pin layout makes me suspect its a high voltage part, possibly a resistor divider network for biasing a CRT electron gun.

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: March 28, 2024, 10:54:20 am
content: Hi Traceless,1.: My guess is delay-line for TV (Thomson),nice resistors, but probably adictive - so send them to me. ;-)))Would like to know the manufacturer.2.: Styroflex-C 27pF3.: Rohm. Arrays of individual Rs exist as well.Best regards

author: Traceless
author_rank: Frequent Contributor
timestamp: March 28, 2024, 11:28:30 am
content: Thanks to everyone for the awesome help.Quote from: Roehrenonkel on March 28, 2024, 10:54:20 amI have quite a bunch of those resistors. Some have odd values (817Ohm, 1.91kOhm) and some surprisingly low tolerances. The best one is 10kOhm 0.001%). Here is a picture of the entire set. For reference I added a ruler and a 7W power resistor. I'm not sure about the vendor all have that trinagle with an Ohm symbol inside maybe that is the manufacturer logo? I'm also not sure what "Rdm" stands for.I found a post in a german forum where somone posted pictures of similar resistors. Someone there stated that those were "high temperature, low drift resistors for radar".

author: wraper
author_rank: Unknown
timestamp: March 28, 2024, 11:41:14 am
content: Those metal can resistors should be worth something. Especially 0.001% one. Most likely some high stability stuff, although I could not find documentation on quick googling. The rest is pretty much junk.

author: Traceless
author_rank: Frequent Contributor
timestamp: March 28, 2024, 06:48:12 pm
content: Out of curiosity I measured the precision 10kOhm resistor, looks pretty good. Here is a screenshot and the data I logged.

author: wraper
author_rank: Unknown
timestamp: March 28, 2024, 11:00:06 pm
content: https://www.diyaudio.com/community/threads/help-me-identify-a-mysterious-device-and-a-resistor-type.406656/Someone said:Quote

author: Traceless
author_rank: Frequent Contributor
timestamp: April 02, 2024, 03:23:41 pm
content: In order to identify the manufacturer of the precision resistors I received a PM with a request for a close-up of the manufacturer logo, which can be found in the image attached.

author: Gyro
author_rank: Super Contributor
timestamp: April 02, 2024, 05:57:20 pm
content: Quote from: wraper on March 28, 2024, 11:41:14 amYes, that one would be worth fitting in a box with terminals to protect the leads - Your first resistance standard.P.S. There are a few other rather nice ones in there. For instance 817k @ 0.02% is pretty good as a high resistance range check resistor. Hermetic wirewounds like that are going to be quite long term stable, especially as they are pre-aged.

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: April 02, 2024, 06:06:22 pm
content: Hi Traceless,there is a Logo-database (for radios and tubes):https://www.radiomuseum.org/m/logos_zz_en_1.htmlMaybe you can find it, i didn't. B-(But there must be a newer version (incl. semiconductor-manufacturers)somewhere in the net, i just can't find it.Best regards

author: Traceless
author_rank: Frequent Contributor
timestamp: April 03, 2024, 08:55:31 am
content: Quote from: Gyro on April 02, 2024, 05:57:20 pmNot a bad idea actually, maybe I should move that idea to the metrology section.@Roehrenonkel: Thanks for the database link I double checked and also didn't find any matching logo so far.Cheers Traceless

author: Traceless
author_rank: Frequent Contributor
timestamp: April 03, 2024, 11:21:41 am
content: @Roehrenonkel: OkayMickle T. solved the logo mystery.The logo belongs to Resista GmbH which apparently is or was a division of Roederstein. I also did a quick search based on the company name and sure enough I found ashop selling "regular" resistors with that logounder the Resista brand.