Test Equipment Anonymous (TEA) group therapy thread

[Cerebus]

Trotting back to the subject of test leads to use with power supplies, I've picked up a few batches of these:



from a vendor on ebay going by the handle casuntek. Here's a listing for them on ebay UK: https://www.ebay.co.uk/itm/5x-4mm-Stackable-Banana-Plug-Wire-Soft-Silicone-Test-Cable-for-Multimeter-1m/232879053961?hash=item3638ac5c89:g:3MoAAOSwQ9ldCMPE.

I bought one lot as a trial order (from an earlier, slightly cheaper listing) some time back and I've been back for more since. Thanks to one of them having a fault (a missing lantern spring) which was sorted out quickly and painlessly by the vendor, I had one cable I could dismantle. Good quality cable, proper copper, lots of cores (55 from memory), generally well made. Good insulation that certainly feels like silicone rubber and strain relief done properly for once. Nominally 15A, 1000V rated, I'd recommend them to anyone who needs some cheap test leads and isn't looking for low-thermal metrology grade.

Anyway, with the mention of horrible voltage drops on leads earlier I though I'd give them a proper 4 wire resistance measurement with my most recent TEA score:



End to end resistance 0.02445 ohms - perfectly respectable. Oh, yes, that is from an Agilent 34461A; and yes, I am sliding down the slope towards volt-nuttery.

The 34461A was scored for a very reasonable £525 a couple of weeks back - so it looks like these are starting to turn up on the secondhand market for sane money. Finally gave up on the hunt for a reasonably priced 34401A and grabbed the 34461A for around £150 more than most good condition 34401As seem to go for. Pristine condition and I get a fancy screen, and an LXi ethernet port and USB to talk to instead of the 34401A's rather awkward GPIB.

So, now I can use a Weston Cell to find out quite how hot it is at the moment. The bonus is that I now have AC measurement good enough to calibrate/verify (at least up to 300 kHz) the HP 3325A sig gen I got a few weeks back. I can get the rest of the frequency range verified, at least to within my comfort zone, by doing some juggling with ratios on the 'scope.

No pictures as I'm feeling too hot and lazy to snap any at the moment but trust me, it looks like it came out of the factory - minus the annoying 'give us your details and you could win...' stickers.

Forgot to say, it came with the handle, all the bumpers and an unused original probe kit.

[bd139]

Nice one  . Totally agree with the situation on 34401A versus a 34461A.

The only thing is I worry about is a 34461A's OLED screen.

[Cerebus]

Edit 2: https://www.ebay.co.uk/itm/153554170494 <-- anyone in UK fancy some storage action?

To quote Richard Thompson: [Fx: sings] "Don't tempt me, Don't tempt me, I'm halfway out of my seat...".

Used to use a Tek storage graphics terminal back in the '70s and I have always had a certain fascination with their storage tubes.

[bd139]

I'm not sure if I'm glad or worried about being an enabler 

[0culus]

I thought about picking up some Kelvin leads to use with my 3455A....then I saw that the leads cost more than twice what I paid for the damn thing. 

[tautech]

I thought about picking up some Kelvin leads to use with my 3455A....then I saw that the leads cost more than twice what I paid for the damn thing. 

This should fix that itch 
https://www.eevblog.com/forum/testgear/franky_s-kelvin-clip-kit/

https://www.ebay.com/str/99centhobbies

[Cerebus]

I thought about picking up some Kelvin leads to use with my 3455A....then I saw that the leads cost more than twice what I paid for the damn thing. 

I bought some Chinese kelvin clips, some silicone test cable, some braided sleeving, some dual banana plugs, pulled some heatshrink out of the bits box and made my own. Total outlay perhaps £20 and as you can see from the graphic above they do a decent job.

[0culus]

Very nice...I shall take a closer look. 

[Kosmic]

The 34461A was scored for a very reasonable £525 a couple of weeks back - so it looks like these are starting to turn up on the secondhand market for sane money. Finally gave up on the hunt for a reasonably priced 34401A and grabbed the 34461A for around £150 more than most good condition 34401As seem to go for. Pristine condition and I get a fancy screen, and an LXi ethernet port and USB to talk to instead of the 34401A's rather awkward GPIB.

Look like a fine dmm, congrats 

[Kosmic]

I thought about picking up some Kelvin leads to use with my 3455A....then I saw that the leads cost more than twice what I paid for the damn thing. 

Yes super simple to make your own. Bought those Kelvin clip because the end was rather small and narrow. Changed the male banana for female. This way I was able to test different cables I already had.



Then I realized that for the LCR meter, Teflon cables were a lot better. With normal long cables (PVC or Silicon) there is so much leakage I can't zero the instrument.



So I'm making a new version with shielded Teflon cables. I'm also planning to use those with my Kelvin Varley resistance bridge.

[BU508A]

Arrived today     



A bit more detailed:



Lots of measuring ahead for characterising them ...     

[Kosmic]

Arrived today     

Hooo really nice. I see you have great taste in term of voltage reference 

[Cerebus]

Chuffing heck! LT-FLUs? Those are like gold dust. Where on earth did you get them, or should I not ask about the masked man seen walking away from the back door of Fluke's production line?

[Kosmic]

I guess you can find those on the dark web   

[bd139]

LTZ1000 is common compared to one of them!

[BU508A]

Chuffing heck! LT-FLUs? Those are like gold dust. Where on earth did you get them, or should I not ask about the masked man seen walking away from the back door of Fluke's production line?

It's not a secret. 

I have bought them here:

https://www.alibaba.com/product-detail/new-and-original-electronic-component-ic_60518077974.html

Walton Electronics in Hongkong Shenzhen. This was my second purchase there.

When I've bought the first lot around 2016 they asked for 25 US$ / piece.

Now they have sold them to me for 30 US$ / piece.

They add the Paypal transaction fee as well (iirc 29 US$ for the second deal)

So, if you want to order (minimum order of 10 pieces) some of them I recommend to have a chat with Ms. Wan Tang and ask for the same price her customer from Germany had some days before. These chinese companies are changing their prices in an instant. When I've visited their site, the price was something between 15 and 25 US$.

But since I know them (we have analyzed the first lot of them) I am pretty sure, that these are genuine parts and no scam or counterfeit.

There is another seller from Shenzen on ebay which is selling LTFLU-1 CH units but I have no idea, how reputable he is.

https://www.ebay.com/itm/183770406682

Mounty

Edit: corrected location

[tggzzz]

Used to use a Tek storage graphics terminal back in the '70s and I have always had a certain fascination with their storage tubes.

They were simultaneously beautiful and a pain in the arse.

[Mr. Scram]

Nice one  . Totally agree with the situation on 34401A versus a 34461A.

The only thing is I worry about is a 34461A's OLED screen.

I thought it's a regular LED or even CFL screen. A benefit of a 34401A is probably the effectively instant boot for quick measurements that don't require fully warming the device up. Obviously it being the standard every subsequent device refers to or emulates adds to the charm. That being said, the 3446X's have their own legacy by now.

If I could take my pick I'd probably go for a DMM6500, but good luck finding one of those for a reasonable price.

[worsthorse]

I thought about picking up some Kelvin leads to use with my 3455A....then I saw that the leads cost more than twice what I paid for the damn thing. 

I am making a set as we speak. Unfortunately, the more I look at the clips I have, the less I like them.  Wondering if these

eBay auction: #252204657919

are worth the price or if folks have another option.

/me, who seems to be on a test lead building kick this week.

[bitseeker]

Nice one  . Totally agree with the situation on 34401A versus a 34461A.

The only thing is I worry about is a 34461A's OLED screen.

I thought it's a regular LED or even CFL screen. A benefit of a 34401A is probably the effectively instant boot for quick measurements that don't require fully warming the device up. Obviously it being the standard every subsequent device refers to or emulates adds to the charm. That being said, the 3446X's have their own legacy by now.

If I could take my pick I'd probably go for a DMM6500, but good luck finding one of those for a reasonable price.

Yep, not OLED per the datasheet: 4.3” color TFT WQVGA (480x272) with LED backlight

[beanflying]

There is good and bad points about both the 34401 and 34461A. My 34401A is slightly more temperature stable by a margin of 20-30%, not the end of the world as I am talking single digit ppm with 10+C temperature swings. The 34461A drops while the 34401A rises in voltage measured against fixed temperature references.

Other than that the 34461A has a lot more going for it with ease of logging etc

I thought it's a regular LED or even CFL screen. A benefit of a 34401A is probably the effectively instant boot for quick measurements that don't require fully warming the device up. Obviously it being the standard every subsequent device refers to or emulates adds to the charm. That being said, the 3446X's have their own legacy by now.

If I could take my pick I'd probably go for a DMM6500, but good luck finding one of those for a reasonable price.

They both need warming up so the boot time 'issue' is a moot point.

[Mr. Scram]

There is good and bad points about both the 34401 and 34461A. My 34401A is slightly more temperature stable by a margin of 20-30%, not the end of the world as I am talking single digit ppm with 10+C temperature swings. The 34461A drops while the 34401A rises in voltage measured against fixed temperature references.

Other than that the 34461A has a lot more going for it with ease of logging etc

They both need warming up so the boot time 'issue' is a moot point.

You don't need warming up for every measurement. 

[GreyWoolfe]

I thought about picking up some Kelvin leads to use with my 3455A....then I saw that the leads cost more than twice what I paid for the damn thing. 

I am making a set as we speak. Unfortunately, the more I look at the clips I have, the less I like them.  Wondering if these

eBay auction: #252204657919

are worth the price or if folks have another option.

/me, who seems to be on a test lead building kick this week.

That is what I used to make mine.  I got some gold plated banana plugs from Frankie and I have some sillycone test lead wire that I bought locally.  In fact, I might get a second set to redo the leads on my DER EE LCR meter.

[mnementh]

I thought about picking up some Kelvin leads to use with my 3455A....then I saw that the leads cost more than twice what I paid for the damn thing. 

I bought some Chinese kelvin clips, some silicone test cable, some braided sleeving, some dual banana plugs, pulled some heatshrink out of the bits box and made my own. Total outlay perhaps £20 and as you can see from the graphic above they do a decent job.

Same here. Also made some "grabbit" probes for my little Chinese component testers the same way.

I am making a set as we speak. Unfortunately, the more I look at the clips I have, the less I like them. 

   Wondering if these eBay auction: #252204657919 are worth the price or if folks have another option.

/me, who seems to be on a test lead building kick this week.

   I looked at those myself, and eventually went with the cheapies like Kosmic used. Mostly because I needed several for the various test jigs I wanted to make, and I wasn't into spending over $100 on just the clips. 

While not as nice in the "screwed together" dept, they do disassemble easily allowing you to solder directly to the metal jaws, which align well and the serrations interlock with no void space. And because they're not priced like they're made of gold-pressed latinum, you don't need to hesitate to grind or file them to shape when you need a custom tip for a sorting sortie or something similar. 

mnem
Pretty is as pretty does.

[mnementh]

TinkerDwagon Time...



There's something viscerally soothing about simple, skilled handwork like shaving a gasket. It's all about the journey: You know where you are, and where you want to be, and the only way to get there is to take it one step at a time, as it comes to you, carefully working your way to the end. 

mnem