Shrouded to non-shrouded test lead converter - Page 1
Forum section: electronics / testgear

author: McBryce
author_rank: Super Contributor
timestamp: February 25, 2016, 12:58:00 pm
content: Hi all,today my HP 3478A (restoration project) arrived and I suddenly released I have a small issue. All of my test equipment up to now is either Fluke or Keithley, they all have shrouded banana sockets and hence, I only own shrouded test leads (other than a few point to point leads) ie: the pin is surrounded by plastic shield. But these don't fit on the HP .I intend using the HP 3478A, but I don't intend buying a second set of all my test leads / kelvin clips etc, just for this meter. Can someone point me to a simple (cheap) converter / mini- extension to convert the shrouded plug to a non-shrouded type?McBryce.

author: jwm_
author_rank: Frequent Contributor
timestamp: February 25, 2016, 01:05:39 pm
content: Just buy some 4mm bullet plugs/sockets and solder them together end to end. works a treat.something like thishttp://www.ebay.com/itm/10-Sets-4-0mm-4mm-RC-Battery-Gold-plated-Bullet-Connector-Banana-Plug-HOT-GOLD-/172101271586

author: AlfBaz
author_rank: Super Contributor
timestamp: February 25, 2016, 01:07:54 pm
content: Forum member iloveelectronics has an ebay store with these and other such nice bitshttp://www.ebay.com.au/itm/4mm-Shrouded-to-Unshrouded-Banana-Plug-Converters-1-Pair-Red-Black-/200904597758?hash=item2ec6d8e0fe:m:m6cIbbrFfVC1R88hIV59YtA

author: F64098
author_rank: Regular Contributor
timestamp: February 25, 2016, 01:15:35 pm
content: Why not using the shrouded input terminal of a 34401A?It has the same pitch of the connectors.The holes in the front plate of the 3478A must be opened to 11,4mmbut there is enough "flesh" to do so.Just my idea...Best regardsFrank

author: McBryce
author_rank: Super Contributor
timestamp: February 25, 2016, 01:24:24 pm
content: Quote from: F64098 on February 25, 2016, 01:15:35 pmA nice neat idea Frank, but how easy is it to find a set of 34401A input terminals?AlfBazs suggestion is exactly what I was looking for, think I'll just order some of them.McBryce.

author: F64098
author_rank: Regular Contributor
timestamp: February 25, 2016, 02:28:54 pm
content: Quote from: McBryce on February 25, 2016, 01:24:24 pmAvailable as spare part: 34401-62121contactcenter_germany@keysight.comHTHFrank

author: free_electron
author_rank: Super Contributor
timestamp: February 25, 2016, 02:29:26 pm
content: just cut the damn shrouds off. whoever invented those shrouded banana's should be tarred , feathered, glued to the wall , covered in red ants and left in the sun.Stupid shrouded wires. compatible with nothing.i never understood the need for those. i get the 'redice risk of touching . but who swaps out live test wires anyway ? engineers are supposed to have more than one working brain cell.

author: McBryce
author_rank: Super Contributor
timestamp: February 25, 2016, 03:37:15 pm
content: They'd look really ugly if I cut them off. I assume they are to conform to one of the CAT standards, but I'm not CAT expert, but I can kind understand why they are there as I used to do it myself: Testing a live system where the leads were connected with crocodile clips, then you go to change meters and don't want to power down the entire system to do that.Either way, I ordered those parts from iloveelectronics, so they should have arrived by the time I've finished restoring the HP. Which brings me to another question: The surrounding bezel at the from of the HP is badly scratched and cracked on the top. Can this be fitted upside down so that it's not as obvious? I'm sure I'll find out as soon as I take it apart. If not, maybe I should go looking for a better conditioned one? First up will be to swap the battery and check the accuracy. It's working (Selftest OK), but I haven't checked anything else yet.McBryce.

author: macboy
author_rank: Super Contributor
timestamp: February 25, 2016, 03:44:04 pm
content: You can also get generic safety banana jacks from ebay (etc.) for well under $1 each.Random example:http://www.ebay.com/itm/262127967052

author: Performa01
author_rank: Super Contributor
timestamp: February 25, 2016, 03:52:34 pm
content: Quote from: free_electron on February 25, 2016, 02:29:26 pmYay!It's so refreshing to see the perfect English translation of my exact thoughts about this stuff, which might be justifiable on a building lot, but not in a lab.

author: nctnico
author_rank: Super Contributor
timestamp: February 25, 2016, 03:54:03 pm
content: I recall seeing banana plugs where the shroud can retract itself so it fits both isolated and 'normal' banana sockets.

author: commongrounder
author_rank: Frequent Contributor
timestamp: February 25, 2016, 04:31:39 pm
content: These: Mueller BU-32101-0 (black) or -2 (red)Excellent quality and very inexpensive (around $3.50 US each)

author: Monkeh
author_rank: Super Contributor
timestamp: February 25, 2016, 04:38:54 pm
content: You can get adapters to fix to the 3478A without modifying anything:http://www.rapidonline.com/cables-connectors/4mm-shrouded-socket-adaptors-63902Just try not to smash them off.

author: LaurentR
author_rank: Frequent Contributor
timestamp: February 25, 2016, 04:54:53 pm
content: Quote from: nctnico on February 25, 2016, 03:54:03 pmI got some in a B&K Precision power supply test lead kit (TPLS)http://smile.amazon.com/gp/product/B0017QLPLEThen I searched far and wide for those and I believe I found the original manufacturer, Calt-Test, who has a number of versions of these retractable banana cables, for instance:I liked them so much I ended up stocking up on various lengths/colors of the CT2148 patch cord (pictured above) and these are the only patch cords I use.http://www.caltestelectronics.com/ctitem/110-plugs-banana-plug-test-leads-stacking-retractable-sleeve-plug-to-stacking-retractable-sleeve-plug/CT2148Very good quality. Retractable, stackable, and the 2148 uses nice silicone wires. The only real downside is that the contact length on the Keysight bench DMMs I have is a bit small. They work, but it could be better.A good source in the US is:http://www.testpath.com/Search.aspx?kw=ct2148Note: I also own some of iloveelectronics's shrouded to unshrouded converters as these are very useful if you want to use specific test leads outside of their basic use (e.g. stacked for multiple measurements).

author: tooki
author_rank: Super Contributor
timestamp: February 25, 2016, 08:25:01 pm
content: Quote from: McBryce on February 25, 2016, 12:58:00 pmThey also make these little adapters that plug into the unshrouded banana jack and then use an Allen key (hex) to lock it in place:https://www.conrad.de/de/uebergangsstecker-stecker-4-mm-buchse-4-mm-schwarz-multicontact-a-slk4-1-st-731468.html

author: Lightages
author_rank: Unknown
timestamp: February 25, 2016, 08:37:07 pm
content: Quote from: free_electron on February 25, 2016, 02:29:26 pmThere are a couple of good reasons for shrouds. One is safety and not just having exposed contacts if pulling them from the socket. The shrouds complete the insulation into the meter so flash over cannot occur to adjacent connections or the front panel if it is grounded. The shrouds also protect the banana plugs from getting touch with dirty hands or surfaces and prevents dirt and contamination from getting on the contact surfaces.

author: TimFox
author_rank: Super Contributor
timestamp: February 25, 2016, 09:18:55 pm
content: If you don't like shrouds, you would love my pre-war Simpson 260 VOM. It uses "pin" jacks, and both the mating plugs and the probe ends have metal nuts to secure the stranded test lead wire, which are open to the touch (about 1/4 inch at each end) just past the plastic handles.

author: McBryce
author_rank: Super Contributor
timestamp: February 25, 2016, 09:53:04 pm
content: @LaurentR: Those retractable ones look pretty cool, but I'd need to replace so many leads I'd go broke.@Monkeh: That's a really neat solution, unfortunately I have already ordered the others. If I'd known about them sooner I would have got them. I might buy them later anyway, depending on how the other adapters go.Regarding cutting shrouds off. I do some vintage radio repair and nixie stuff, so I prefer having the shroud for the added safety. 200VDC deserves some respect.McBryce.

author: McBryce
author_rank: Super Contributor
timestamp: March 03, 2016, 10:19:13 am
content: Just swapped the battery in the 3478A. I bought a Panasonic BR 2/3A with single tab at one end and double at the other end (like the footprint on the PCB), but the tabs are on the wrong end (double tabs on positive terminal)So I had to cut off the double tabs and solder a single lead at that end. Very confusing. Either way, it all worked fine and I didn't loose the Cal dataI've given it a quick sanity check using a few voltage and resistor standards I have here and also compared it to my Keithley 2000 which I know to be extremely accurate and the 3478A seems to be pretty spot onThe original battery was the original black EternaCell (from 1984 as far as I can tell). It still read 3.02V, but I'm told the device was powered up more or less permanently by its last owner, so it was never really used.Now I just need to finish the restoration. The case cleaned up nicely and I've glued the crack that was in the front bezel and it's looking better now. I'd like to swap the bezel completely if someone has one to offer. The feet are also missing (it was rack-mounted at its last home), so if anyone (in Europe) has a spare set of 3478A feet and/or the front outer bezel, let me know.The device is the version with the transformers, not opto-isolators, should anyone want to know.McBryce.

author: engineer_in_shorts
author_rank: Regular Contributor
timestamp: March 03, 2016, 10:34:35 am
content: Quote from: Performa01 on February 25, 2016, 03:52:34 pmNot at all - i am upset that my Fluke 8508A does not have shrouded sockets (which is lab equipment). It means i have to have a set of test leads with the shrouds cut off.If you are routinely calibrating hand held meters then you are injecting up to 1000V - I personally like test lead shrouds in case one day i have a brain fart and forget to switch off a calibrator output.

author: joeqsmith
author_rank: Super Contributor
timestamp: March 03, 2016, 10:55:39 am
content: Quote from: nctnico on February 25, 2016, 03:54:03 pmI bought this meter brand new for home and this is how the original leads that came with it worked. Good idea but not as safe as the modern ones.OP, did you get yours with GPIB? I got mine with the HPIL which is useless today....

author: McBryce
author_rank: Super Contributor
timestamp: March 03, 2016, 11:50:53 am
content: It's the GPIB version luckily.I'm not 100% sure, but I think the 3478A with the smooth sides (and plastic bezel) are GPIB and the 3478A with the two ridges along the side (and aluminium bezel) are HPIL. But I may be completely wrong there?McBryce."Smooth" version:https://76.img.avito.st/1280x960/833964276.jpg"Ridged" version:http://www.wie-tec.de/bilder/bild/2981/2981_1.jpg

author: Performa01
author_rank: Super Contributor
timestamp: March 03, 2016, 01:31:02 pm
content: Quote from: engineer_in_shorts on March 03, 2016, 10:34:35 amWell, if someone is dealing with really high voltages regularly, they actually might feel more comfortable with shrouded plugs.That said, I'm using my calibrator up to 1000V quite often, and not so much for calibrating DMMs, which I don't consider risky at all, as it's a straight connection, but mainly for leakage tests on capacitors, relays and other stuff for precision instruments, where leakage currents <1pA are required. That means connecting components isn't as simple as just plugging a pair of cables, but using the usual lab accessories, like clamps and hooks. Even if they are compatible with shrouded plugs, it wouldn't make much sense, as there inevitably will be exposed contact materials anyway, at the very least on the d.u.t. itself.Still I don't worry about that, because I can set up the test unhurriedly on the bench and instinctively follow the rule to use just one hand at a time when fiddling with the leads, plugs, accessories and d.u.t. whenever higher voltages might be present.And then - how much current do you have available at 1000V? I don't think I've seen any calibrator that would output more than 10W, often less. That leaves you with a couple of mA, which might 'bite' you, but certainly not cause any electrical injury.

author: engineer_in_shorts
author_rank: Regular Contributor
timestamp: March 03, 2016, 02:15:18 pm
content: Quote from: Performa01 on March 03, 2016, 01:31:02 pm

author: McBryce
author_rank: Super Contributor
timestamp: March 07, 2016, 08:40:10 pm
content: Quote from: AlfBaz on February 25, 2016, 01:07:54 pmMy converters have already arrived from HK!! Well done that man! (99centhobbies) No idea how he managed to get them here that fast, stuff from HK usually takes 10 times longer.Now I just need to work out a new puzzle about my HP 3478A: Why are the 2 wire measurements more accurate than the 4 wire measurements?? Tested with several standards and compared to my Keithley. Example: 20K000 0.01% Resistor: HP 2 Wire = 19.9998, HP 4 wire = 19.9961, Keithley 20.0001.McBryce.

author: daddario
author_rank: Regular Contributor
timestamp: March 07, 2016, 10:30:35 pm
content: As an ad hoc solution I once found that the Deltron stacking banana plugs without the plastic part work as excellent quality shrouded plug to regular socket adapters. As a bonus you can attach a wire ( :

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: March 08, 2016, 12:02:24 am
content: The iloveelectronics appear to be marked 30V Max. This seemed too low for my tastes, which why I just bought some inexpensive probes and cut the shrouds off.I like the idea of soldering those two adapters together that the first poster jwm mentioned.

author: joeqsmith
author_rank: Super Contributor
timestamp: March 08, 2016, 12:12:14 am
content: Quote from: McBryce on March 03, 2016, 11:50:53 amBack then, I was not doing anything with HPIB. I bought mine with the plastic case that has the handle on it, which is different than what you show.

author: Monkeh
author_rank: Super Contributor
timestamp: March 08, 2016, 12:13:40 am
content: Quote from: FlyingHacker on March 08, 2016, 12:02:24 am... that's because they're unshrouded.They're not going to burst into flames if they see 31V. Or 1000V.

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: March 08, 2016, 01:55:56 am
content: Quote from: Monkeh on March 08, 2016, 12:13:40 amThat was what I figured, but if it was a problem I didn't want to forget and put B+ through them and have an issue. But if there is no issue the. Perhaps I will order some.

author: mos6502
author_rank: Frequent Contributor
timestamp: March 08, 2016, 03:33:27 am
content: Test leads with spring loaded locking shroud (to retract you have to push a button), stackable:http://www.sks-kontakt.de/index.php?option=com_virtuemart&Itemid=128&lang=enOr you could always make your own.Plugs with spring loaded retractable shrouds:http://www.hobbyking.com/hobbyking/store/__77403__4_0mm_Banana_Safety_Plug_Kit_4pc_.html14AWG silicone insulated cable:http://www.hobbyking.com/hobbyking/store/__42752__Turnigy_Pure_Silicone_Wire_14AWG_1m_Red_US_Warehouse_.htmlhttp://www.hobbyking.com/hobbyking/store/__42753__Turnigy_Pure_Silicone_Wire_14AWG_1m_Black_US_Warehouse_.html

author: BravoV
author_rank: Super Contributor
timestamp: March 08, 2016, 03:47:56 am
content: I have retractable shrouds banana too, personally I prefer this kind of detachable shroud, too bad its never made into test lead.Example from Philips BNC to banana converter, its made from quality and rigid plastic and not wobbly nor flimsy. The shrouds are very firm when attached, while its easy to detach too by releasing the two latches.Examples with shrouds attached :Without shrouds :

author: McBryce
author_rank: Super Contributor
timestamp: March 08, 2016, 10:15:18 am
content: Quote from: FlyingHacker on March 08, 2016, 12:02:24 amYour probes instantly became 30V parts when you cut the shrouds off. 95% of my work is below 20V anyway, so this isn't an issue for me.I gave the iloveelectronics parts a go last night. They are a bit longer than they need to be which means the probes stick very far out from the meter, but otherwise they work fine. The fit is relatively tight and the connection feels solid.McBryce.

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: March 08, 2016, 04:19:25 pm
content: Quote from: McBryce on March 08, 2016, 10:15:18 amLOL. They only became 30V if I touch them!I wouldn't want to put 1000V through those cheap probes ever, anyway.Sadly, vintage meters have non-shrouded connectors. Many of them don't have space to install them, either.

author: McBryce
author_rank: Super Contributor
timestamp: March 08, 2016, 08:19:09 pm
content: The HP 3478A looks like it would have enough space for shrouded sockets, which is why I am still considering the idea that F64098 suggested on page 1. I have a few shrouded sockets here, so I'll take a look at the possibilty at the weekend when I open it up again to fit the rubber feet I ordered.McBryce.