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Post by Philconut on Aug 24, 2023 18:45:38 GMT 12
I recently acquired several clip leads. Today, I used them for the first time to connect the 6.3V heaters of valves in an amplifier to a transformer. I couldn't see any glow from the heaters at all. On measuring the voltage at at one of the valves, it was 3.5 volts. After eliminating the transformer, the only other components were the 2 leads. Each lead had a DC resistance of 1.4 ohms so 2.8 ohms in the circuit - a significant problem! A close investigation revealed 2 problems. 1, V ery small conductor, 2. the cables were only crimped into the crocodile clips. I hadn't noticed at the time, but a retest revealed that the leads got quite warm. I've replaced the wiring & soldered all the joints. Problem solved and amplifier satisfactorily tested. Who would have anticipated this?   |
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Post by Bob Killip on Aug 24, 2023 19:11:33 GMT 12
I agree, It's a common problem. Crocodile/alligator leads from Jaycar in particular, are not fit for purpose. I usually de-crimp them and start over with solder but even that's not very successfull; the clips just bend sideways like jellyfish teeth (do they have teeth?) and only grab a cross-section of a few microns (it seems like that).
Anyone know of a good source of "real" clips?? I got plenty of wire to build my own wandering leads.
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Steve
Society Members
vintageradio.co.nz
Posts: 732
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Post by Steve on Aug 25, 2023 13:30:49 GMT 12
I've had exactly the same problem, and solved it in the same way - I just re-terminate them. If I need to run heaters or some other current-requiring load with the clippy leads then I replace the wire with that from an old PC power supply - because the wire in the cheap leads is all plastic and a few strands of fine copper in the middle just so they can say they did - while the wire used in PC power supplies is generally pretty grunty. If I was making them from scratch I'd probably just get them from RS: nz.rs-online.com/web/c/test-measurement/test-connectors/crocodile-clips/They used to have free shipping, but they don't any more... so there is that to consider... There are two sizes of clippy leads, I don't buy the small ones any more. I normally buy these from Surplustronics: surplustronics.co.nz/products/2575-crocodile-leads-set-of-10-300mm-lead-large-clipsWhile those are still cheaply made, I find them more reliable and the clips more rugged. Cheers, Steve |
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Post by elorens on Sept 4, 2023 15:35:41 GMT 12
I've had exactly the same problem, and solved it in the same way - I just re-terminate them. If I need to run heaters or some other current-requiring load with the clippy leads then I replace the wire with that from an old PC power supply - because the wire in the cheap leads is all plastic and a few strands of fine copper in the middle just so they can say they did - while the wire used in PC power supplies is generally pretty grunty. If I was making them from scratch I'd probably just get them from RS: nz.rs-online.com/web/c/test-measurement/test-connectors/crocodile-clips/They used to have free shipping, but they don't any more... so there is that to consider... There are two sizes of clippy leads, I don't buy the small ones any more. I normally buy these from Surplustronics: surplustronics.co.nz/products/2575-crocodile-leads-set-of-10-300mm-lead-large-clipsWhile those are still cheaply made, I find them more reliable and the clips more rugged. Cheers, Steve Thanks for the tip, Steve. I just ordered some of these leads from Surplustronics and am happy with them. |
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Post by Bob Killip on Sept 6, 2023 18:35:28 GMT 12
I went to surplus electronics (Sound Division) today & bought the larger wandering leads pack of 10 (2 x 5 colours)... around $10. They look way more rugged so thanks for the advice.
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Post by Bob Killip on Sept 13, 2023 18:32:52 GMT 12
A cautionary tip regarding the Surplustronics leads... to my frustration, the wire is poorly crimped (pierced) to the clip and the lead can lose continuity; trust me, it happened with these. (there's nothing worse when fault-finding, than an intermittant connection to device under test). I've gone thru the whole set, opened the crimp, and soldered the lead to the clip then re-crimped. Right... that should do it!
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peter
Tinkerer
Retired, collector of vintage radios and test equipment for restoration and repair.
Posts: 97
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Post by peter on Sept 22, 2023 2:50:44 GMT 12
I too was caught out by el cheapo leads with croc clips - I used them to try that Lithium Ion battery restore where you connect the terminals of a good battery to a bad one. They simply melted!! I was gobsmacked.
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