Siglent SDM3065X - Poor Banana Socket Connections - Is this a known problem? - Page 1
Forum section: electronics / testgear

author: t1d
author_rank: Super Contributor
timestamp: November 24, 2024, 11:36:47 am
content: I am just a hobbyist. Though I purchased my 3065X a good many years ago, it has only been used occasionally and very gently.I am noticing that I am getting really poor connectivity, no matter what type, or brand, of banana probe/cable I am using. For any and all, I must insert the banana plug, short the cable to calibrate it, read the (initially high) connectivity and twist the banana plug, until the calibration reading drops to a reasonable value. Then, I hit the "REL" function key. Needless to say, I wonder if the connection has worsened, as I move the probe/cable around, to use it. That's not a confidence builder...So, I am wondering a few things...1) Is this a known problem, for this unit?2) Are the OEM banana sockets of poor quality? If so, does anyone know of a good repair/replacement video, or tutorial?3) Maybe the sockets just need to be cleaned? I have never cleaned them, so maybe there is some tarnish. I could use a video, or tutorial, for that, as well.Thanks to everyone for your help! (Maybe tautech will come along and clue me in. I hope so.)

author: KungFuJosh
author_rank: Super Contributor
timestamp: November 24, 2024, 04:35:19 pm
content: What do you have Aperture/PLC set to?It's a little difficult to tell from your description, but sounds maybe more like a filtering issue than a cable issue.I've not had any trouble with any bananas on my SDM meters.

author: tooki
author_rank: Super Contributor
timestamp: November 24, 2024, 04:59:58 pm
content: Quote from: t1d on November 24, 2024, 11:36:47 amFYI, a regular Q-tip is the perfect size for cleaning banana jacks. There are many electronic contact cleaners on the market, but even just some alcohol would quickly make visible if there is significant corrosion. (Though I’d lightly oil the surfaces afterwards if you use alcohol. Contact cleaner like deoxit is better.)

author: nctnico
author_rank: Super Contributor
timestamp: November 24, 2024, 05:21:13 pm
content: I'm more inclined to think there is a defect inside the meter. Maybe a bad solder joint. It is hard for a banana socket to corrode to a point where the contact gets really bad. It is also not clear what kind of measurement the OP has trouble with.

author: tautech
author_rank: Super Contributor
timestamp: November 24, 2024, 06:40:28 pm
content: Quote from: t1d on November 24, 2024, 11:36:47 amNot at all.You might be lucky first to mention it.Have you checked the fuse holders ?How do the OEM test leads behave ?Are you using Lantern style banana leads ?

author: t1d
author_rank: Super Contributor
timestamp: November 26, 2024, 09:55:28 am
content: Thanks to everyone! Great replies and information!I will try to give some replies...Quote from: KungFuJosh on November 24, 2024, 04:35:19 pmI would think it mechanical, because I can clear it by twisting the plug.Quote from: nctnico on November 24, 2024, 05:21:13 pmIt occurs with all types of measurements. A bad joint certainly is a possibility, but I think it best to try tooki's simple cleaning suggestion, first. I had considered cleaning, originally, but thought it best to get some information, before doing anything, so as to avoid a bad mistake. I do have IPA and MG Nutrol Control Cleaner. The Nutrol makes a mess, when sprayed. I will spray it on a Q-Tip and apply it, after cleaning with the IPA.Quote from: tautech on November 24, 2024, 06:40:28 pmNo, I have not checked the fuse holders. I am not sure how they would be involved, as I am not having any power issues?Oh, you probably mean the over-current protection fuses, on the probes. Well, again, I can clear the problem with twisting. I would think that a problem with a fuse would be rather static (corrosion) and not cleared the same way.The OEM leads and all of the other brands and types suffer the same connectivity problem. And, they are all cured with the same twisting method.Yes, I use mostly Lantern style banana leads. You make a good (quality) consideration. However, as said, I have the issue with all plug types, probe qualities and brands. No one type seems to be less prone to having the issue.Having been reassured about cleaning being an appropriate, gentle first step, I will give that a try and report back. If cleaning does not result in improvement, I will open the unit and give the sockets a visual inspection.Maybe the sockets are of poor quality and don't use strong tubes. If they are split tubes, perhaps they need to be closed a bit. Or, if they are some sort of a leaf spring, they might need to be bent inward. I have not found a tear down video that shows the details of the sockets. I imagine tautech can tell us.Thanks to everyone!

author: tautech
author_rank: Super Contributor
timestamp: November 26, 2024, 10:00:19 am
content: Quote from: t1d on November 26, 2024, 09:55:28 amSee the POI list with links to pics:https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/

author: t1d
author_rank: Super Contributor
timestamp: November 27, 2024, 02:12:49 pm
content: Quote from: tautech on November 26, 2024, 10:00:19 amThanks, tautech!I searched the link for three separate terms = 1) "socket" 2) "banana" 3) "4mm".None of these terms returned any information pertaining to 1) poor 4mm banana socket connectivity, or anything that would indicate that there would be a picture of the banana sockets that the SDMs use. The only information about poor probe connectivity appeared to be concerning thermal K probe issues, not the meter's banana socket. YMMV.Of course, I used these terms, and others, to search this site and the web, as well, for information related to the Siglent SDM 3065X DMM.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 27, 2024, 02:33:37 pm
content: With poor sockets of plugs there are 2 possible problems that are not directly related:1) higher than normal and unstable resistance, which is especially a point with a 2 wire resistance measurement.A bit extra resistance should not so much effect the voltage readings.2) relatively high thermal EMF and thus sensitive to thermal gradients from handling the wires. This would to some degree also show up in resistance, but also with low voltages (200 mV range). The error tends to go down over few minutes after handling the cable. Often this problem is more an issue with the plugs and not so much the sockets.The probably best test on the connection is 2 wire ohms with a short.

author: KungFuJosh
author_rank: Super Contributor
timestamp: November 27, 2024, 03:57:43 pm
content: You don't live near the beach do you?I've never heard of any issues with these banana sockets at all, but...In over 30 years of repairing guitars, the most abnormal corrosion on hardware was from people that lived close the beach (salt water).