Fluke TL175 DVM Test Leads - UK Vintage Radio Repair and Restoration Discussion Forum

Jon_G4MDC · 9th Jun 2022, 10:59 am

I wonder if anyone else has had trouble with these?

I have a pair which came with a Fluke 177 DVM that I purchased new about 3 years ago.

Both Red and Black developed high resistance at the connection between lead and probe. They measured about 0.6 Ohm each where normally the reading would be ~0.1 Ohm. They were sensitive to movement as if the inner conductor had broken.

Initially I blamed myself for wrapping them around the meter when not in use so causing flexing in the strain relief. Eventually it got bad enough to want to do something about it and I cut them open at the apparent break and resoldered.

Normal service was resumed for a while but now they have gone back to the old behaviour.

I have them opened up again at the old cut and my soldered joint is still fine. Tugging there didn't pull out wire from another break but it has restored the resistance to 0.1 Ohm! Now I'm thinking that the real dodgy joint must be down inside the body of the probe but I have no idea how, or if, it would come apart.

Has anyone been here before please? I would like to repair them to use on another knock about DVM for less critical duty. I know they are no longer any good for CAT III 1000V! For the 177 I have already bought replacements.

chriswood1900 · 9th Jun 2022, 12:44 pm

I had a similar problem with only the red lead just where the lead enters the probe body, I bought a new pair and chopped the probes off and reused the leads with some crocodile clips on the end. I have found the moulded leads very hard to repair safely hence replacing them, I don't like taking chances on leads which I use for measuring high voltages.

Lloyd 1985 · 9th Jun 2022, 4:16 pm

I don’t know what model Fluke leads I had at work, but they went just like yours! They got replaced eventually, took some doing, but tape bombs on each probe soon got health and safety’s attention! Best way to get anything replaced!

Regards
Lloyd

Jon_G4MDC · 9th Jun 2022, 7:19 pm

I like your tactics! Pity I have to be my own H&S inspector.
It seems this problem is not unknown then.

On closer inspecetion the new replacements have some differences to the originals. The mouldings are slightly different. The CAT III labelling differs. The new ones carry US patent numbers while the old ones had none.

I have heard people call out fake for less! I don't suppose they are but I wonder if the ones that are bundled in with DVMs are some "cost down" version which have been pared to the bone on everything?

I doubt it's possible to repair them but I still hope to try.

The prods will not unscrew. I added torque which I judged to be just short of the twist + shearing point. Thinking about the next move.

The Philpott · 9th Jun 2022, 8:01 pm

-You might have to apply unreasonable force in the name of reverse engineering!

(Goes to show you never can tell- my Micronta/Tandy leads are some of the best i have, must be 32yrs old now- all four terminations re-made as a precaution)

Dave

Jon_G4MDC · 9th Jun 2022, 9:28 pm

I might!

I'm also thinking about a possible port mortem move. Slit them longitudinally from end to end to open them up for inspection.

9th Jun 2022, 10:59 am	#1
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Fluke TL175 DVM Test Leads I wonder if anyone else has had trouble with these? I have a pair which came with a Fluke 177 DVM that I purchased new about 3 years ago. Both Red and Black developed high resistance at the connection between lead and probe. They measured about 0.6 Ohm each where normally the reading would be ~0.1 Ohm. They were sensitive to movement as if the inner conductor had broken. Initially I blamed myself for wrapping them around the meter when not in use so causing flexing in the strain relief. Eventually it got bad enough to want to do something about it and I cut them open at the apparent break and resoldered. Normal service was resumed for a while but now they have gone back to the old behaviour. I have them opened up again at the old cut and my soldered joint is still fine. Tugging there didn't pull out wire from another break but it has restored the resistance to 0.1 Ohm! Now I'm thinking that the real dodgy joint must be down inside the body of the probe but I have no idea how, or if, it would come apart. Has anyone been here before please? I would like to repair them to use on another knock about DVM for less critical duty. I know they are no longer any good for CAT III 1000V! For the 177 I have already bought replacements.

9th Jun 2022, 12:44 pm	#2
chriswood1900 Octode Join Date: Jan 2007 Location: Dorridge, West Midlands, UK. Posts: 1,483	Re: Fluke TL175 DVM Test Leads I had a similar problem with only the red lead just where the lead enters the probe body, I bought a new pair and chopped the probes off and reused the leads with some crocodile clips on the end. I have found the moulded leads very hard to repair safely hence replacing them, I don't like taking chances on leads which I use for measuring high voltages. __________________ Chris Wood BVWS Member

9th Jun 2022, 4:16 pm	#3
Lloyd 1985 Nonode Join Date: Jun 2008 Location: Coningsby, Lincolnshire, UK. Posts: 2,819	Re: Fluke TL175 DVM Test Leads I don’t know what model Fluke leads I had at work, but they went just like yours! They got replaced eventually, took some doing, but tape bombs on each probe soon got health and safety’s attention! Best way to get anything replaced! Regards Lloyd

9th Jun 2022, 7:19 pm	#4
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: Fluke TL175 DVM Test Leads I like your tactics! Pity I have to be my own H&S inspector. It seems this problem is not unknown then. On closer inspecetion the new replacements have some differences to the originals. The mouldings are slightly different. The CAT III labelling differs. The new ones carry US patent numbers while the old ones had none. I have heard people call out fake for less! I don't suppose they are but I wonder if the ones that are bundled in with DVMs are some "cost down" version which have been pared to the bone on everything? I doubt it's possible to repair them but I still hope to try. The prods will not unscrew. I added torque which I judged to be just short of the twist + shearing point. Thinking about the next move.

9th Jun 2022, 8:01 pm	#5
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,107	Re: Fluke TL175 DVM Test Leads -You might have to apply unreasonable force in the name of reverse engineering! (Goes to show you never can tell- my Micronta/Tandy leads are some of the best i have, must be 32yrs old now- all four terminations re-made as a precaution) Dave

9th Jun 2022, 9:28 pm	#6
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: Fluke TL175 DVM Test Leads I might! I'm also thinking about a possible port mortem move. Slit them longitudinally from end to end to open them up for inspection.