$20 LCR ESR Transistor checker project

[elepo]

OK I found this post https://www.eevblog.com/forum/testgear/lcr-t4-mtester-v2-07-lcr-meter-black-block-issue/msg872669/#msg872669 and I think I have figured the pinouts. I finally managed to get "something" into the display. Gonna play with it a bit.

[madires]

Have you tried the settings for the T3/T4 clones listed in the Clones file? There are two different pinouts for the display.

Which file exactly? I have the clone comparison PDF and the models PDF but they don't have the pinouts.

The source code of the m-firmware comes with a file named 'Clones'.

[elepo]

The source code of the m-firmware comes with a file named 'Clones'.

Ah yes. The configs are listed there and they work.
Thanks yet again.

[elepo]

I've faced another problem.
In my clone (LCR-T4) the PD4(T0) pin is connected to LCD reset.
The documentation keeps saying it can be shared with the LCD but it can't.
When I open the frequency counter or ring tester function, after a few seconds the LCD is reset and I only see a green screen until I reset the device.
 

Is there any hope for me?

[madires]

No surprises there! Sharing the display's reset line with another signal doesn't work, but sharing SCK or MOSI works fine. You can blame the clone designer for the poor pin assignment. As work-around you could cut the trace and hardwire the LCD's reset line via a resistor to 3.3V.

[elepo]

No surprises there! Sharing the display's reset line with another signal doesn't work, but sharing SCK or MOSI works fine. You can blame the clone designer for the poor pin assignment.

Is the reset functionality not needed at all?
It's listed as "optional" in the config file but I'm not sure how optional it is.

As work-around you could cut the trace and hardwire the LCD's reset line via a resistor to 3.3V.

Ugh that's really undesirable but I guess I have no choice.

[madires]

It's nice to have the MCU control /RESET and /CS, but to save pins you can hardwire both. That's the reason why both signals are optional in the configuration. Some clones have hardwired /CS for example. However, there can be also drawbacks based on the specific pin assignment. WIth a hardwired /CS no other SPI chips can be attached to the bus, like a touchscreen controller.

[elepo]

It's nice to have the MCU control /RESET and /CS, but to save pins you can hardwire both. That's the reason why both signals are optional in the configuration. Some clones have hardwired /CS for example. However, there can be also drawbacks based on the specific pin assignment. WIth a hardwired /CS no other SPI chips can be attached to the bus, like a touchscreen controller.

I see. I'll probably cut the trace then.
Mine has CS shorted to gnd.

[Regina]

I, I'm new here. Not a total newb, but skills are mad rusty. A google search of the fish48840 led me here. Rather than searching the 300 pages here, can I just be lazy and ask what some common problems it may have where it will not turn on at all? It worked years ago when I bought it, but now seems dead. No electrolytic or tants in sight. What could be wrong with this thing. Not advanced enough to be updating firmware and the like. Just want to be able to use it again. I tried the test button down for the 3+ seconds, but nothing, not even backlight. Any ideas? I don't have an ESR tester and usually don't have to mess with surface mount. I mean, I guess I could if I had to, but not something I am used to. Not like lifting a lead of a cap and checking it out of circuit.

[madires]

Welcome to the forum! First thing to check is the power supply. When you push the test button does the voltage regulator output 5V?

[BDX18]

Howdy,

I decided to get one of these testers, but based on what I saw on eBay and read here (the last 10 pages), looks to me there are many different versions, and I presume some may be better than others.

Can someone recommend me a few models that would be good buys for one reason or another?

Obviously, I want something that can be updated to the latest firmware -- that's a must.
Having a faster CPU, more memory, a better LCD or a case are all nice to have.

[Feliciano]

Welcome to the forum.

Because there are many options available of hardware and/or firmware, I would start by looking the clone comparison chart posted on the last couple of pages (shared by indman and madires). Knowing which specs and options each hardware offers, you can narrow your choices.

And after you buy it and you're familiar with it, you can flash an OSHW firmware to further improve that.

[madires]

Anyone speaking Hungarian? A user from Hungary needs some help with the firmware.

[yo0]

Any comments about this model?

https://a.aliexpress.com/_mOqwxsG

Best regards

Pio

[madires]

Looks like a GM328A with a nicer design. Should be fine.

[indman]

Any comments about this model?

This model is presented in my table of clones, and photos of its internal content can be viewed in the "GM328A(BGR)1" folder on my resource https://yadi.sk/d/yW8xa5NJgUo5z   

[morgan_flint]

From indman's photos, it seems to have the components for extended frequency measurement and zener testing... am I right?

[indman]

it seems to have the components for extended frequency measurement and zener testing... am I right?

No, this clone has the same feature set as the regular GM328A

[morgan_flint]

Ok, I thought these components were for the frequency measurement prescaler and zener voltage boost, but they must be for something else

[indman]

3 chips that are marked in red are the maintenance of the BGR display, and voltage boost are marked in red is the node for powering the tester from + 5V(USB-С,microUSB)

[madires]

Is that setup similar to the ST7735 semi-compatible display? IIRC, that display had a level shifter and an MCU emulating an ST7735.

[indman]

madires,yes, it's 99% likely! It is enough to look at the white frame of the distinctive display to understand that this is a BGR semi-compatible.

[madires]

So LCD_SEMI_ST7735 might work for that new design as well. Let's wait and see.

[Feliciano]

But I was thinking, according to indman's table of clones, that it was already supported. Isn't it?

[DarthMalgus]

Hey guys, after reading a lot about these cheap testers i decided to buy one for myself. There was a post analyzing their differences and i decided to go with this "M328" from aliexpress: https://www.aliexpress.com/item/32797552392.html

Despite the seller pictures i received a black PCB with all SMD components but luckily the 328p processor was socketed. It looks exactly like this tester: https://www.banggood.com/GM328A-LCD-Transistor-Tester-Diode-ESR-Meter-PWM-Square-Wave-Generator-Soldered-Module-p-1384846.html

The firmware was 1.12k on it. I bought a new processor and a 20Mhz crystal and i upgraded to a 1.37m firmware version which i got online. The archive name is "AY-AT-Markus1.37En(20Mhz)" so it should work with the new crystal Found the source of this firmware after posting: https://disk.yandex.ru/d/yW8xa5NJgUo5z/GM328A (It should be compatible)

Now with the new processor and crystal the tester takes 10 seconds to boot up and everything is slow and laggy. My issue is that i don't know how to make the hex and eep files for this tester on my own. Is there a place to get the latest firmware for this clone or any guidance on how to make it myself ?
Did i miss some other important modification to make the tester work with the m-firmware or could this simply be a case of a bad processor or incompatible firmware ?

Thank you