SOLVED: “LCR-T7” tester - reliable?  - Page 1
Forum section: electronics / testgear

author: eti
author_rank: Super Contributor
timestamp: December 26, 2022, 06:42:25 am
content: https://www.amazon.co.uk/ARCELI-LCR-T7-Transistor-Tester-Capacitance/dp/B07V688CJP/ref=mp_s_a_1_2?crid=22E68KA5ZFP63&keywords=tc7+tester&qid=1672036747&sprefix=tc7+tester%2Caps%2C73&sr=8-2I recently saw some info where folk have bought this tester (and the “LCR-T1” variant) and had issues with them failing after a short time - something to do with caps going short.Any feedback would be helpful before I dive in and get one.Many thanks. Happy Christmas to you! 😃Update: got me an “Arcelli” LCR-T4 (My favourite version of the tester) for a mere £7.99 with next day Shipping on Amazon Prime, so went for that instead.

author: tooki
author_rank: Super Contributor
timestamp: December 26, 2022, 09:43:04 am
content: All of these testers share the same core design. If it were inherently unreliable we wouldn’t have this insanely long thread about them:Code:eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/(Sorry, the dollar sign in the URL makes it impossible to link to)

author: Swainster
author_rank: Frequent Contributor
timestamp: December 26, 2022, 12:36:25 pm
content: In my experience (of a single T7 version), it has been fine, surviving the last 15 months of light use and a couple of incompletely discharged capacitor accidents without any failures. Of the 3 chinese component testers that I've got, it's still the favourite.

author: bffargo
author_rank: Regular Contributor
timestamp: December 26, 2022, 08:46:22 pm
content: Beware, with the lack of cheap authentic ATMEL ATMEGA328 chips, in the last 6 months or so more of these clone testers have started putting in clone chips and changing firmware. They may no longer have the same accuracy or even support from the various open source project that started the entire series of these. See the last many pages of the massive thread:https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/8025/

author: elecdonia
author_rank: Frequent Contributor
timestamp: December 27, 2022, 01:45:15 am
content: Quote from: bffargo on December 26, 2022, 08:46:22 pmI agree. I’ve purchased several transistor tester units over the past 5 years. Until about 1 year ago nearlyallof them contained Atmel MCU chips, usually theATmega328.However, due to price increases and the current scarcity of raw IC chips, a single Atmel ATmega-series MCU chip is now priced higher than a complete transistor tester. Therefore the transistor tester manufacturers have substituted non-Atmel MCU chips whichcannotrun any of the existing open source software.The only way to assess “which MCU” is if the vendor provides a photo of the PC board. But few (if any) vendors of these LCR units enclosed in plastic cases show photos of the PC board. Many vendors maynotknow which MCU is inside the unit they are selling.For the LCR-TCx and LCR-Tx units I don’t think the TC1, TC2… or the T4, T7… numbering scheme is as meaningful today as it used to be. Several manufacturers now make these units. Their model numbers are often inconsistent with each other.

author: elecdonia
author_rank: Frequent Contributor
timestamp: December 27, 2022, 01:54:01 am
content: Quote from: Swainster on December 26, 2022, 12:36:25 pmWould it be feasible for you to post a photo of the PC board inside your LCR-T7 so that we could learn what MCU chip is in it?I’ve been trying to get a LCR-T7 which contains the Atmel ATmega324 MCU. This chip has 44 pins (11 pins on each of its 4 sides). But everything I’ve received so far contains some other incompatible MCU. Some MCU chips were incorrectly labeled (on purpose) or their labels had been sanded off.

author: eti
author_rank: Super Contributor
timestamp: December 27, 2022, 02:23:17 am
content: Does anyone here in England have an LCR-T1 or LCR-T7 with a *genuine* Atmel chip to sell?

author: Swainster
author_rank: Frequent Contributor
timestamp: December 27, 2022, 03:51:20 am
content: Quote from: elecdonia on December 27, 2022, 01:54:01 amHad a look inside. There is only one sanded off chip, and it's not the main MCU. That said, the laser etching on the MCU was almost unreadable, though it improved after a wipe with IPA. There was actually some stray solder stuck between a couple of the pins though it wasn't making electrical contact - I removed it just in case it decided to cause problems in the future.

author: ledtester
author_rank: Super Contributor
timestamp: December 27, 2022, 04:10:12 am
content: To embed a link to the transistor tester thread, substitute %24 for the $, e.g.:https://www.eevblog.com/forum/testgear/%2420-lcr-esr-transistor-checker-project/8025/will link to reply 8025.

author: Swainster
author_rank: Frequent Contributor
timestamp: December 27, 2022, 05:57:55 am
content: Oh, I just noticed that my component tester actually says LCR-TC2 on the front. I dont know why I thought it was a T7... though then again it says T7+ on the PCB

author: eti
author_rank: Super Contributor
timestamp: December 27, 2022, 06:19:31 am
content: Quote from: eti on December 27, 2022, 02:23:17 amAttention!! ^ urgent

author: py-bb
author_rank: Regular Contributor
timestamp: December 27, 2022, 07:45:05 am
content: Quote from: eti on December 27, 2022, 06:19:31 amI really like mine but it did take a while to arrive from China, happy to buy another one if mine's of use:IC's an APT32F172I really like it, very useful device, I was skeptical at first because .. well ebay and ships from China right?As others have noticed the soldering work is sub-par - there's a little spatter on blank areas of the board on mine but it was cheap and very useful and gives consistent readings so I'm happy overall.

author: eti
author_rank: Super Contributor
timestamp: December 27, 2022, 04:47:23 pm
content: Quote from: py-bb on December 27, 2022, 07:45:05 amThat’s very kind but I’m looking for one with a genuine Atmel IC. What do you want for it?

author: Pfriemler
author_rank: Regular Contributor
timestamp: December 27, 2022, 04:52:03 pm
content: Bought a LCR-T7 in August 2022 via Amazon. Compared to my two GM328A bad performance, wrong measurements, does not recognize double shottkys and so on. Drift on R measurents -30% within 10 minutes.Sent it back.edit: this amazon thing must have been a fake. The "IR feature" did only recognize "Hitachi", others only with a flickering button.Meanwhile, I have a JOY-IT labeled new one from German reichelt: way better performance, and decodes NEC perfectly.

author: py-bb
author_rank: Regular Contributor
timestamp: December 28, 2022, 01:32:20 am
content: Quote from: eti on December 27, 2022, 04:47:23 pmEnough to cover P&P and the cost of a new one and I'm happy. As long as I'm not out of pocket.It's basically brand new, it arrived on the 23rd (it took a while obviously from China), but as I'm UK also you'd get it much quicker. They're better than you'd think and I fully intend to replace it if you do buy it from me. I just don't mind waiting for a replacement.

author: eti
author_rank: Super Contributor
timestamp: December 28, 2022, 04:17:46 am
content: Quote from: py-bb on December 28, 2022, 01:32:20 amI appreciate it very much, but times are tight for now. I think I’ll wait it out for an Atmel-based model. Thanks so much for the offer though. Happy 2023! God bless you.

author: elecdonia
author_rank: Frequent Contributor
timestamp: December 28, 2022, 03:08:31 pm
content: Quote from: Swainster on December 26, 2022, 12:36:25 pmThanks for the PC board photos of yourLCR-T7. Your unit contains a genuine AtmelATmega324MCU. This is confirmed by the MCU chip having 11 pins on each side, 44 pins total. This 44 pin package is unique to the Atmel MCU chip family which includes theATmega324and theATmega644.The other Atmel MCU chip frequently used in transistor testers (ATmega328) has 8 pins on each side, 32 pins total.To the best of my knowledge all of the alternate Chinese MCU chips recently showing up in transistor testers also have 32 pins. Some are (deliberately) mislabeled as ATmega328. However their pinout and internal functionality is completely different.The Chinese manufacturers have cobbled together their own proprietary firmware. Its quality varies:1) Usually several of the expected transistor tester features are missing2) Some measurement results may be very inaccurate3) It is impossible to upgrade or replace this proprietary firmwareAt this timenoneof the extensive library of open-source transistor tester software/firmware supportsanyof these alternative Chinese MCU chips.

author: elecdonia
author_rank: Frequent Contributor
timestamp: December 28, 2022, 03:15:10 pm
content: Quote from: Swainster on December 27, 2022, 05:57:55 amThe LCR- model number suffixes ( TC1, TC2, T7, T7+, etc.) printed on the outer case of these units seem to be randomly interchangeable. I haven’t yet determined whether the internal labeling on their PC boards is meaningful.

author: py-bb
author_rank: Regular Contributor
timestamp: December 29, 2022, 02:03:47 am
content: Quote from: elecdonia on December 28, 2022, 03:15:10 pmWhen I was buying one I was wondering about that, the specifications given on ebay listings are very poor, I decided based on pictures of things shown measured. The specs are also wrong like the one I have is supposed to top out at measuring 5Mohm, it measured 9.7 earlier.I've also found that it'll measure certain features only between certain ports, so say 1 and 3 is generally better (measures more) than 1 and 2.I'll take some pictures of mine soon - it can't hurt.That said I really like it. It's unusual in that it's a better product than the listings imply.

author: elecdonia
author_rank: Frequent Contributor
timestamp: December 29, 2022, 06:50:25 pm
content: Quote from: py-bb on December 29, 2022, 02:03:47 amWhen you getdifferent resultstesting thesame resistor(or capacitor) on different ports of the transistor tester (such as 1-2, 2-3, or 1-3) this means you need to perform the "self calibration" procedure. To do this you first need to assemble 3 very short wires (< 2 inches) twisted or soldered together. Then place them into the ZIP socket on the tester to short out all three port pins at the same time (1, 2, and 3). Next press power button on tester. Display should be "selftest." After some time passes it will display "isolate probes." Now remove the shorting wires. Selftest will continue and eventually the tester will shut off. Next time you test a resistor (or capacitor) the result should be nearly identical no matter which set of test ports (1-3, 1-2, or 2-3) the component is connected to.Note: Inductors and some other 2-wire components may require using ports 1 and 3 to test.

author: py-bb
author_rank: Regular Contributor
timestamp: December 29, 2022, 07:08:58 pm
content: Quote from: elecdonia on December 29, 2022, 06:50:25 pmNot what I meant, I meant like say we put a capacitor between 1 and 3, you'll get an ESR and a drop %age out of it as well as a capacitance, put the same capacitor on 1 and 2 and you get just capacitance."" for diodes (but different readings)

author: indman
author_rank: Super Contributor
timestamp: December 30, 2022, 07:55:48 am
content: Quote from: eti on December 26, 2022, 06:42:25 amHi! Why create duplication and many topics for discussing the same device, if there is a global topic where this project is discussed and one of the respected authorsmadiresparticipates? In this way, you are spraying valuable information that would be useful to other people.And so you have to jump from one branch to another, instead of just using a search service that normally works on the forum.

author: eti
author_rank: Super Contributor
timestamp: December 30, 2022, 09:44:01 am
content: Quote from: indman on December 30, 2022, 07:55:48 amGood point. Thanks. Happy 2023! Thanks for your hard work. It’s appreciated.

author: elecdonia
author_rank: Frequent Contributor
timestamp: December 30, 2022, 04:07:05 pm
content: Quote from: py-bb on December 29, 2022, 07:08:58 pmYes, there areenhancedmeasurement features for capacitors and inductors. These functiononlywith ports 1-3. Availability of these features depends on which firmware is in the tester. I need to re-read the official transistor tester documentation again - I know these enhanced features exist but I haven’t yet studied them in depth.

author: py-bb
author_rank: Regular Contributor
timestamp: January 01, 2023, 02:56:14 pm
content: Quote from: elecdonia on December 30, 2022, 04:07:05 pmWhoa whoa whoa:you found a manual?- I got nothing with mine. I had todiscoverthe 1-3 port thing!BTW mine says T7 but if I do that firmware trick (press power button 4 times - I needed to unplug the battery to get it out of "bootloader mode") it says TC1 bootloader!Also mine has wrong specs, ebay's listing said it could measure up to 5Mohm - I've tested 9.4Mohm just fine - I've not seen how high it can go.Share the manual!

author: elecdonia
author_rank: Frequent Contributor
timestamp: January 02, 2023, 11:42:15 pm
content: Quote from: py-bb on January 01, 2023, 02:56:14 pmThe Chinese rarely offer manuals. Sometimes they provide a one-page summary which is frequently so inaccurate that it is useless But the two original creators of the Transistor Tester (Karl-Heinz Kubbeler and Markus Resche) frequently update their 100+ page comprehensive technical manuals. I attached their most recent English versions. They are also available in Russian and perhaps some other languages. Please keep in mind that these manuals won't be fully applicable to units where the Chinese have cobbled together their own versions of the official Transistor Tester software.QuoteThe bootloader has a 5 minute timeout. Then the unit shuts off. Next power-up will operate normally in component tester mode. I attached a photo of the bootloader screen from my LCR-TC1 unit. Is the bootloader screen displayed by yours identical or slightly different? Please post a photo if you can.QuoteThat ebay listing was missing a 0 after the 5. The correct maximum resistance that can be measured is 50M. I haven't yet tested a resistor that large with mine.QuoteManuals attached below

author: py-bb
author_rank: Regular Contributor
timestamp: January 13, 2023, 09:21:01 pm
content: Quote from: elecdonia on January 02, 2023, 11:42:15 pm

author: Tangent_Tracker
author_rank: Regular Contributor
timestamp: May 01, 2024, 02:07:42 pm
content: Did this version work ok? Can't believe the price hike though!