$20 LCR ESR Transistor checker project

[madires]

Also I'm not sure which pins I should use with a SSD1306 I2C :

Code: [Select]

#define I2C_SDA          PD0            /* port pin used for SDA */
#define I2C_SCL          PD1            /* port pin used for SCL */

If I understand correctly, PD0, PD1 are used for the UART interface on an Arduino Uno.

Yep, they go to the USB2serial converter. Try two unused pins and change the pin/port configuration accordingly. And don't forget the external pull-up resistors for I2C.

[Maniaxx]

In continuous mode a short button press will skip any delay. Two short button presses trigger the main menu, and a long button press will power off the tester. So we would need something else. Any suggestion?

What about this:
- Add an option in 'config.h' to enable 'short press' for pause/freeze so rotary controller users can have both functions (short press=pause and rotate right=skip).
One-button device users can also use this (but obviously lack 'rotate right'). They could decide to pick a short auto-continue time or keep the old behavior.

[indman]

@madires:
Can you add a 'hold' function (button press) for 'continuous mode' so we have time to write down values? On problematic PCBs (covered in collophonium) the continuous mode is better/faster. Generally, i prefer auto-hold mode though.

I don't understand, what is the point of adding such an option?
If you need to examine the measurement data in detail, use the AUTO-HOLD mode.
If there is not enough time to review the results in continuous mode, simply increase the pause in the setting config.h
#define CYCLE_DELAY   
Why reinvent the wheel and the bicycle? 

[madires]

What about this:
- Add an option in 'config.h' to enable 'short press' for pause/freeze so rotary controller users can have both functions (short press=pause and rotate right=skip).
One-button device users can also use this (but obviously lack 'rotate right'). They could decide to pick a short auto-continue time or keep the old behavior.

Implementing that would require to change/check all TestKey() calls which is a ton of work. And it would also increase the firmware to some extend. Not very motivating.

[Maniaxx]

Another option would be an 'auto-hold on success' where 'success' is true by either a found semiconductor or predefined threshold (lowcut) for caps (>30pF) and R (>30 Ohm). That would cover the idle range (impact) when holding cables.

[hotnuma]

And don't forget the external pull-up resistors for I2C.

Thanks a lot @madires, I managed to upload the hex and eep to an Arduino Pro Mini 5V 16 MHz.

Now I have a weird behavior, when I try to test a 1µF cap between 2-3, the device finds most of the time non existing caps with large values such as 89 µF 144 ohms between 1-3 or 949 µF 144 ohms between 1-2 etc... and sometimes it finds the right value among wrong ones, for example 1090 nF 0.87 ohms which is the correct reading.

I enabled ADC_LARGE_BUFFER_CAP for resistors but other than that I don't know what I can do.

Thanks in advance. 

[madires]

That's a common issue when powering the tester with an SMPSU. Please try a linear PSU. The essential settings for Arduino based testers are listed in the Clones File.

[madires]

Another option would be an 'auto-hold on success' where 'success' is true by either a found semiconductor or predefined threshold (lowcut) for caps (>30pF) and R (>30 Ohm). That would cover the idle range (impact) when holding cables.

That could be feasible.

[fpisi]

I bought a GM328A tester from AliExpress with Russian language by mistake. I wanted to change its language, so bought another English one and tried to read its flash but was locked. I also bought developer boards with same microchips, so I have spare ones.

I also downloaded Markus Frejek and  Karl-Heinz projects from GitHub and built my own hex, but unfortunately it didn't work.

Tried the hex file from here: https://github.com/robsoncouto/gm328a_rev_eng, but couldn't get it work.

Anyone has a working English flash, hex file for this latest version tester?

[indman]

fpisi,try this firmware

[lezginka_kabardinka]

Hi friends.

Like to change 'fake' Chinese IC part for genuine "Mega328P U-TH" on device "LCR-T4" (Unit with USB-C port, as seen since silicon downfall)...  = possible?

Thank. u

/update/: Image of downfalled item attach.

[lezginka_kabardinka]

CIyf pstèuri š″h′èfitèu, âl″ytènyg″èrè âfèš″uašèhèmrèkIè zèfèdèu k″al″fy. Ak″ylrè zèhèšIykI g″uazèrè âIèš″y, zyr zym zèk″oš zèhašІè azfagu dèl″èu zèfyŝytynhè fae?

Problem to understand? I speak from Adyghe, sorry have bad English, Circassia! :

[Fuzzy Star]

Like to change 'fake' Chinese IC part for genuine "Mega328P U-TH" on device "LCR-T4"   = possible?

See these posts:
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4762751/#msg4762751
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4745147/#msg4745147
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4742351/#msg4742351

[Stinger]

Hi,

Can i flash these LCR-T4 V2.68 clone with CH341a USB programmer ?

[madires]

Yes, if your CH341a USB programmer supports ISP.

[morgan_flint]

I bought a GM328A tester from AliExpress ...
Anyone has a working English flash, hex file for this latest version tester?

I also bought one of these "new version" of GM328A to add to my collection (my TEA is severe...). If the FW posted by indiman doesn't fit, I can try to make a backup of mine, which is in English, if it's not protected.

Also, @indiman, I see this version is not in your table of clones; if you want to include it and need more details, I'd be happy to contribute. It seems genuine 328P for <14€, and I bought it also because, form the photos in the ad, it seemed to have a DC/DC converter that I thought was for zener measurement (but I think it's not) and something that seemed a prescaler for frequency (also think it's not, but up to now I haven't analised it too much).

[Circlotron]

Haven’t read the whole thread, it’s a bit long. Got one of these things yesterday and every electrolytic cap I measure it shows ESR as zero ohms. Am I doing something wrong or are some of these testers a bit dodgy?

[madires]

Have you done the self-adjustment?

[Circlotron]

Have you done the self-adjustment?

No. It did not come with any instructions. Where could I find these?

[madires]

Short-circuiting all three testpins should trigger the self-adjustment. I don't know if there's a manual for the T4 clone, but please see Karl-Heinz' documentation for the k-firmware (https://github.com/kubi48/TransistorTester-documentation).

[LeWidget]

Hi all. I was looking to get one of these testers but tossing up between the TC1 & T7. Which one is more useful, reliable, easier to repair if something goes wrong ?

https://www.aliexpress.com/item/1005005237553083.html?spm=a2g0o.productlist.main.3.3fc517ecauDpV2&algo_pvid=f153996f-afd1-4412-bd4a-b646f44233fb&algo_exp_id=f153996f-afd1-4412-bd4a-b646f44233fb-1&pdp_npi=4%40dis%21AUD%2154.17%2119.51%21%21%2133.88%21%21%402103228816963420811975338e03f6%2112000032317691182%21sea%21AU%211614096062%21&curPageLogUid=GZo8cWxUPCuz

https://www.aliexpress.com/item/1005005430295628.html?spm=a2g0o.productlist.main.1.3fc517ecauDpV2&algo_pvid=f153996f-afd1-4412-bd4a-b646f44233fb&algo_exp_id=f153996f-afd1-4412-bd4a-b646f44233fb-0&pdp_npi=4%40dis%21AUD%2142.75%2121.37%21%21%21195.72%21%21%402103228816963420811975338e03f6%2112000033040265575%21sea%21AU%211614096062%21&curPageLogUid=7Wh4HQxFGkdT

[madires]

Make sure to choose a clone with a genuine ATmega. Currently many clones are sold with APT32F172K8T6 or LGT8F328.

[LeWidget]

Make sure to choose a clone with a genuine ATmega. Currently many clones are sold with APT32F172K8T6 or LGT8F328.

How do you find that out? Reading the description of the products does't mention anything about what chip they come with :/

[lezginka_kabardinka]

Make sure to choose a clone with a genuine ATmega. Currently many clones are sold with APT32F172K8T6 or LGT8F328.

You make it sound like "a choice" 

[madires]

How do you find that out? Reading the description of the products does't mention anything about what chip they come with :/

It's a lottery at the moment, but there are some hints:

We have seen popular clones sold in multiple variants with genuine ATmegas and
alternative MCUs, some even with fake ATmega markings. When buying a clone it
can be hard to identify the MCU. Some hints:
- MCU in DIP is usually an genuine ATmega.
- APT32F172K8T6 has different power pins:
  - 32-LQFP/QFN: 18=Vss, 19=Vdd (ATmega328 32-TQFP: 5=Gnd, 4=Vcc)
- APT32F172K8T6 uses SWD port for ISP:
  - 5 pins: Vdd, Vcc, F_SDAT, F_SCLK, F_RST
- Testers with APT32F172K8T6 often lack a quartz crystal.
- LGT8F328 has slightly different pins:
  - QFP32L: 21=PE2/SWD (ATmega328 32-TQFP: 21=Gnd)
- LGT8F328 uses SWD port for ISP:
  - 5 pins: Gnd, Vcc, SWD, SWC, Reset
- Clone variants with an genuine ATmega are usually about EUR/US$ 5 more
  expensive than the variant with a different MCU.

Your best bet is to look for an DIP ATmega or to build a tester yourself.