Meter Probes for HP 3478A - Page 1
Forum section: electronics / testgear

author: PicoPete
author_rank: Newbie
timestamp: January 07, 2022, 05:12:47 pm
content: I just acquired an HP 3478A multimeter on eBay at a song-and-dance-price (have not received it yet) and noticed a similar purchase for the same meter said their meter leads "did not fit". Can anyone confirm whether the HP 3478A requires a specific size or brand of meter probes and if so some possible sources, or will the current variety of meter probes commonly available work? Thanks in advance.

author: AVGresponding
author_rank: Super Contributor
timestamp: January 07, 2022, 05:36:41 pm
content: They are standard 4mm banana jacks; however due to its age it takes unshrouded plugs.I like Pomona6322(iirc) which have retractable shrouds.EDIT: Pomona model number is 6366, I was close!https://www.mouser.co.uk/datasheet/2/159/d6366_100-1514949.pdf

author: Shock
author_rank: Super Contributor
timestamp: January 07, 2022, 05:51:15 pm
content: You shouldn't be live plugging the probes in anyway with a voltage on but remember you can just carefully cut shrouds off to convert a pair of probes.

author: bdunham7
author_rank: Super Contributor
timestamp: January 07, 2022, 06:06:25 pm
content: They're just 4mm banana jacks but they won't accept safety shrouded plugs which is what most DMM leads are nowadays. IMO the best option is a retractable-shroud plug which will work in almost any meter and still protects you from damage if the lead is accidentally pulled out of the meter while connected to power. The Probemaster 8018S is one example.https://probemaster.com/8000-series-test-leads-only/

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: January 08, 2022, 07:12:14 am
content: Or you could install Staeubli A-SLK4 adaptors on the jacks.

author: rvalente
author_rank: Frequent Contributor
timestamp: January 08, 2022, 12:44:54 pm
content: To fix the probes just cut them with utility knife and that is done...I've never found much usefulness in shrouded banana plugs. How would live something connected on mains and the probes hanging in thin air? They're of course an extra layer of safety but not necessary

author: alm
author_rank: Super Contributor
timestamp: January 08, 2022, 01:12:27 pm
content: I find the extra layer of protection comforting when measuring higher voltages up to 1000V DC. Mostly in case the plugs partially unplug and then I might brush my hand against them when grabbing the meter. But I guess what helps with the 3478A is that the meter is limited to 300V, so you shouldn't be measuring anything beyond it. Not that voltages below 300V can't be lethal, but it limits the potential energy.If all you're planning for is measuring circuits powered by bench supplies, akaSELV, I wouldn't care at all and use simple unshrouded banana plugs.

author: PixieDust
author_rank: Frequent Contributor
timestamp: January 14, 2022, 09:44:48 pm
content: I too picked up a 3478A not long ago. I bought the Probe Master retractable sheath leads. Work really nicely, snug fit. Get two pairs, so you can do 4 wire resistance measurement. I got two of these:https://probemaster.com/8000-series-test-lead-master-kits/Look for 8044K.

author: DavidKo
author_rank: Frequent Contributor
timestamp: January 19, 2022, 08:32:56 am
content: I expect, that orignal from Keysighthttps://www.keysight.com/zz/en/product/34137A/deluxe-test-lead-set-3458a.htmlwill probably work (it works with 3457a).

author: DavidKo
author_rank: Frequent Contributor
timestamp: January 19, 2022, 07:47:31 pm
content: I have forgot for one solution that I use also commonly and it is banana socket extension. They are only 30V rated, but you can use any shrouded test leads without modification.Left to right: Cut shrouding, adapter, Keysight