Design a New Precision LCR Tweezers with Much Lower Cost 【Shannon Tweezers ST42】

[tautech]

Might I inquire what bench LCR meter you use?

Also to clarify - does the ST42 do well for identifying bad caps?

I’m most likely to be working on through hole parts and larger filter caps…. Sounds like the ST42 is better suited to smaller components?  Though I get the impression they are valuable all around…

See Reply #678 for my views as a SMD tweezer convert of nearly 2 decades.

While large/old axial caps do provide a challenge to measure it can be done very successfully by spreading the tweezers to make them fit. On very rare occasions I have soldered a wire onto large components.

No cap tester will tell you if a cap is good or bad and some experience and common sense should be applied.
Measuring a selection of good/new and old/used will get you there but also knowledge of how the cap is used and if it's under any significant ripple abuse which kills caps.

For my repair needs and general component measurement I have never seen the need to invest further than what good tweezers can provide.

[Zucca]

See Reply #678 for my views as a SMD tweezer convert of nearly 2 decades.

For our mental sanity, here

[KungFuJosh]

Might I inquire what bench LCR meter you use?

Also to clarify - does the ST42 do well for identifying bad caps?

I’m most likely to be working on through hole parts and larger filter caps…. Sounds like the ST42 is better suited to smaller components?  Though I get the impression they are valuable all around…

My bench meter is an ST2832 (an improved TongHui unit, but it's an understatement to say SourceTronic is WAY better at support than TongHui).

Yes, you can use the ST42 to identify bad caps. You do that by measuring capacitance and ESR. If either are out of spec, you know it's probably bad. That's the extent of what you'll usually get out of LCR meters to test whether a cap is good or not.

For axial leaded caps, if they have long enough leads, I fold them inwards so I can still use the ST42 if I don't feel like turning on the bench meter.

As tautech mentioned, there are ways around the size limitations. Whether or not that's convenient for you really depends on the frequency you need to test larger stuff with short leads.

The DE-5000 is a well respected tool, and you can't really go wrong between that and the ST42. I think it's better to own both of them instead of just one if you aren't also getting a bench LCR. ST42 + bench LCR is perfect for my needs.

[Zucca]

No cap tester will tell you if a cap is good or bad and some experience and common sense should be applied.

... I see a Sencore LC103 in the corner with a grumpy face.

[KungFuJosh]

No cap tester will tell you if a cap is good or bad and some experience and common sense should be applied.

... I see a Sencore LC103 in the corner with a grumpy face.

Probably grumpy because it's missing it's cal files and working at defaults (out of spec), and can't zero out its leads...all that assuming it can even power on. 😉😉

I think I would enjoy one of those if it was 100% operational / reliable and not thousands of dollars on the used market.

[TomKatt]

Considering purchasing the ST42...  Just curious - of those who purchased these, are the optional curved contact points worth getting?  Looks like the curved set might offer a bit better ergonomics for board use?  Or are the base model points good enough for general purpose use?

Thanks!

EDIT - impulse buy got the better of me and I just ordered the set with the optional curved tips     Found an $18 Aliexpress coupon online that basically got me the tips for free, so what the heck.  More parts is betterer, right ? 

[KungFuJosh]

Just curious - of those who purchased these, are the optional curved contact points worth getting?

I guess you'll let us know which you prefer. 😉

[Cyclotron]

Just curious - of those who purchased these, are the optional curved contact points worth getting?

I guess you'll let us know which you prefer. 😉

I'm interested in the feedback too. I decided to forgo the curved blades for now.  I don't know what I'm missing, but I've enjoyed using the tweezers. They have certainly saved me a lot of time.

[shapirus]

My set of curved tips is still sitting in the box. Never tried them. I guess it's gonna be just a spare set of tips for me.
I've been happy enough with the straight tips ever since the ST42 arrived.

[unmaker]

I want to buy these tweezers but aliexpress won't let me. After 7 failed purchase attempts I've given up for the moment. I've ordered many times from aliexpress and this is the first time I've encountered this issue. There seems to be a workaround which is to place the order without any coupons. The $18 coupon I'm trying to use is a nice discount and I don't want to place an order without it.

[Martin72]

Maybe tautech can help you.
I for example thought I was ordering directly from shannon, but was also redirected to Aliexpress.
My ST42 is due to arrive this week.

[tautech]

Maybe tautech can help you.
I for example thought I was ordering directly from shannon, but was also redirected to Aliexpress.
My ST42 is due to arrive this week.

Nope, buying through AliExpress like everyone else.
Got 11 coming.

[Martin72]

If you don't need them all for yourself, you could sell him one, that's what I meant by helping.

[KungFuJosh]

Maybe tautech can help you.
I for example thought I was ordering directly from shannon, but was also redirected to Aliexpress.
My ST42 is due to arrive this week.

Buying from aliexpress is the same thing as buying direct from Shannon.

I will also likely be selling them for the US market, but I have to figure out what the selling price will need to be for it to make sense to resell them given all the stupid processing fees and such I have to deal with here.

[KungFuJosh]

I want to buy these tweezers but aliexpress won't let me. After 7 failed purchase attempts I've given up for the moment. I've ordered many times from aliexpress and this is the first time I've encountered this issue. There seems to be a workaround which is to place the order without any coupons. The $18 coupon I'm trying to use is a nice discount and I don't want to place an order without it.

That means the coupon can't be used for your order. I tried applying a similar coupon in the cart, and it also said some BS about security.

[TomKatt]

I want to buy these tweezers but aliexpress won't let me. After 7 failed purchase attempts I've given up for the moment. I've ordered many times from aliexpress and this is the first time I've encountered this issue. There seems to be a workaround which is to place the order without any coupons. The $18 coupon I'm trying to use is a nice discount and I don't want to place an order without it.

That means the coupon can't be used for your order. I tried applying a similar coupon in the cart, and it also said some BS about security.

I had the same problem.  It took several attempts to get the coupon to work.  My order would go through but then immediately be cancelled or “expired”.  I’m not sure what I did any differently on the last attempt, but my order eventually went through and my order was shipped today.

I’m not familiar with Aliexpress - I think this may be the second time I’ve ordered from them.

[Personwithhats]

Does anyone else have issues with the  tweezers constantly loosing charge?
I've started using them more often (Purchased August last year) but nearly every time I take them out I need to charge.

[thm_w]

Does anyone else have issues with the  tweezers constantly loosing charge?
I've started using them more often (Purchased August last year) but nearly every time I take them out I need to charge.

No, are you on recent FW? I assume they auto-shutoff without an issue.
Maybe the cell has gone bad. If you have a USB current meter you can run them flat then charge them up to get an idea of the internal cell capacity in mAh.

[KungFuJosh]

Does anyone else have issues with the  tweezers constantly loosing charge?
I've started using them more often (Purchased August last year) but nearly every time I take them out I need to charge.

No, I rarely ever charge them. Which firmware do you have?

[Personwithhats]

Says it's on v1.5.3 and some kind of BL: LOCKED entry
I'll see if I can test the cell

[TurboTom]

Does anyone else have issues with the  tweezers constantly loosing charge?
I've started using them more often (Purchased August last year) but nearly every time I take them out I need to charge.

Maybe the same issue that I reported about a year ago (my own fault)? https://www.eevblog.com/forum/testgear/design-a-new-precision-lcr-tweezers/msg4861124/#msg4861124

[Kean]

I also had some issues with the battery discharging when not in use, and just as TurboTom mentioned it was because the quick ref card was pushing down on the button/joystick when I put the tweezers back in the case.  No further issues once I started being more careful about placement of the quick ref card.

[Personwithhats]

Uh, removed reference card,  lets see if that helps

[KungFuJosh]

🤣

If that's really the cause here also, then Shannon should take note of it. lol

[tautech]

🤣

If that's really the cause here also, then Shannon should take note of it. lol

Box full of ST42 arrived today.....none had the reference card stuffed into the case....they were loose in each packet.
Shannon does take note of what we tell him......