Wire choices - Page 1
Forum section: electronics / repair

author: Vgkid
author_rank: Super Contributor
timestamp: February 13, 2024, 01:29:04 am
content: Up until this point, I have never had to replace internal instrument wiring. Unfortunately i'm working on a piece of gear where the internal wires have broken off. It is solid core roughly 20awg. I'm looking at replacing it with stranded, but what should i replace it with in regards to jacket/indulation. This would be below 300v , and not low noise/high insulation(ptfe/fep) . Though if suitable options , it will be for precision stuff. I believe pvc might have been used originally.Thanks.

author: donlisms
author_rank: Frequent Contributor
timestamp: February 13, 2024, 04:21:18 am
content: What are your specific concerns? That is, is there something rolling around in your brain that would make you unsure of just using some fairly ordinary wire? I'm just thinking, so far, that seems fine.I am kinda curious about the previous wire being "kinda heavy" and solid. Usually that would be in a situation where the wire needs some particular physical layout, bent with nice right angles to keep the spacing right, that kind of thing. So... eh... what'cha working on?Just a thought - I measure nearly everything in my lab with digital calipers that can convert inches to millimeters. And I look up diameters on a copper wire gauge table. Immensely satisfying when I want to be sure about wire gauges and other thicknesses! (E.g., is this 6.00mm or 6.35mm?). I love these things. Use 'em all the time.

author: Vgkid
author_rank: Super Contributor
timestamp: February 13, 2024, 06:22:43 pm
content: I'm repairing a calibrator, where all of the wires going to the main panel are bent at right angles, unfortunately that is where the breaks are. I think I'm overthinking this.

author: Greybeard
author_rank: Frequent Contributor
timestamp: February 13, 2024, 06:32:10 pm
content: Which calibrator is it?

author: Vgkid
author_rank: Super Contributor
timestamp: February 13, 2024, 07:36:02 pm
content: DAS-46

author: jpanhalt
author_rank: Super Contributor
timestamp: February 13, 2024, 07:50:10 pm
content: If you have a piece of the original wiring, you can determine whether it is PVC very easily with a flame test.

author: Vgkid
author_rank: Super Contributor
timestamp: February 13, 2024, 10:54:24 pm
content: Sure do , will look into it.

author: watchmaker
author_rank: Unknown
timestamp: February 14, 2024, 11:59:54 am
content: I remember in my voced days (tubes) that we were repeatedly told you HAD to pay attention to wire routing in order to reduce unwanted effects. While I do prefer stranded, solid makes this easy. Do you have room to secure the stranded in the original positions?Any idea why the solid failed? Is the time to failure so short as to be a maintenance issue?

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 14, 2024, 01:46:00 pm
content: The General Resistance DAS series relies on their very good resistors. I would think that any minimal change in the wire resistance would be significant. Also I do not know what solder they used. That might also be important. Exact placement of the wires probably is important.I think General Resistance used pure copper wires and I would think that exact replication of the physical wires would be the best solution.I do not think the wires are tinned, you can check this easily.I would not use stranded.You are correct, this is precision stuff.

author: Kosmic
author_rank: Super Contributor
timestamp: February 14, 2024, 02:16:08 pm
content: Could you post some pictures ? also highlighting the section you want to replace in the schematic could be helpful. The manual is here :http://bee.mif.pg.gda.pl/ciasteczkowypotwor/General%20Resistance/General_Resistance_DAS_40_50_60_70_80_Dial-A-Source_Voltage_and_Current_Sources_Service_Manual.pdfPersonally when restoring something I try to be as authentic as possible. So I would be tempted to find some solid core wire.

author: Vgkid
author_rank: Super Contributor
timestamp: February 15, 2024, 07:34:11 pm
content: I will post some pics. I will give its own thread.

author: TechnicsHiFiFan
author_rank: Newbie
timestamp: February 16, 2024, 03:04:19 am
content: Hi VgKidWhen i had to replace my Technics wire, i looked at the old wire and it had a UL number on it, and traced it back - original wire was tinned annealed copper. I used this recently it can be purchased at Newark which is like Element14 or Digikey maybe would stock it. Its tinned copper, hasnt the shine of the old300v wire, maybe yours is like thishttps://au.element14.com/multicomp-pro/24-15085/jacket-material-pvc/dp/2819026

author: tooki
author_rank: Super Contributor
timestamp: February 16, 2024, 07:00:35 am
content: Quote from: Vgkid on February 15, 2024, 07:34:11 pmPlease don’t. Use the existing one.

author: r6502
author_rank: Regular Contributor
timestamp: February 17, 2024, 05:58:33 am
content: hello Vgkid,I own a DSA56, and did some repair on the unit. In my unit the CSA and the reference was defect. I did a schematic of the original CSA, but decided than not to repair it, but to replace it with a more modern chip the LT2057. The reference was also upgraded to one with the LM399, see here:https://www.eevblog.com/forum/metrology/general-resistance-das56a/25/For rewiring, I used the most of the original wires, as normally you would not open the unit on a dayly base. During repair, some wires broke close to the solder joint, in this case I cleaned the solder joint, removed the rest of the broken wire, striped the insulation from the wire and put all back togeter athe original position. it's working perfect ... until now. The existing wires that broke during my repair, have all been long enough.At a few points, where I did some rewiring with new wires, I took flexinle wires, as I did not had solid wires in stock. This was done for the AC line input wiring.GuidoEdit: spelling

author: Vgkid
author_rank: Super Contributor
timestamp: February 18, 2024, 07:57:02 am
content: Your thread was one of many I had read, and your problem was similar to mine. Unfortunately a switch also went flaky, which was why this turned into a debacle. With not wanting more wires to break.