TC1 lcr-meter transistor-tester fix

[ssimic71]

Hi guys, what is wrong with my LCR TC1? It shows unreadable number in measurements, like in the given figure.

tnx,
Sasa

[madires]

Was it working before? Did it start suddenly or became worse with time?

[ssimic71]

That how it was when I first turn on. Until now, I tryed just to calibrate it, and that was succesful. Although, during calibration, also showed this peculear numbers in percentages.

[madires]

In case the tester works fine besides the weird digits it could be a bad firmware. Since the tester is new I would ask the seller for a replacement.

[ssimic71]

It was bought from Aliexpress, the seller is informed about the problem, but I do not expect miricle.
The idea of refreshing firmware is ok to me. Could you please direct me how to upgrade, and where to find latest files.

Thank you very much
Sasa

[madires]

That depends on the specific model you have. Current models come often with an alternative MCU, making it hard to get any firmware. Genuine ATmegas are supported by the two OSHW firmwares. Please post a picture of the PCB and I might be able to identify the MCU type.

[ssimic71]

Here are the pictures, there are no markings on mcu.

[madires]

Looks to be an LGT8F328 (one of the alternative MCUs), i.e. not supported by the OSHW firmwares.

[ssimic71]

Tnx for clarifying.

[wickedrc]

Hi Guys, and congratulations for this useful forum!

I've in trouble with a TC1 tester (version with ATMEGA324PA)

It's been broken after a check of a charged capacitor 

I've check it, and I've found broken DZ2 and U1.

I've changed them, now the tester starts, but I've backlit blank screen 

Can someone explain how to flash the U1?

I've already bought a USBasp-H6P interface, and I've soldered a connector to tester PCB (as in picture)

Thank you so much!

[vinhlg]

Hello all,

Does anyone have the schematic diagram of this TC1 version?

My TC1 broken, LCD display is total black. When I press "Start" L1 becoming very hot. It seems a short-cirtcuit somewhere?
Any advices? Thanks.

--- update ---
I think I found the reason: U1- LGT8F328 is dead - almost short circuit between PIN 4 (VCC - 5V) and PIN 5 (GND). Removed U1 and I have light on display - (of course nothing).
It was my mistake: I check capacitor during charging the battery of LC1 - because I saw low voltage.
Lesson learned.

Solution is replacement of U1 and reprogramming it. I think.

[madires]

... if you're able to find the firmware for the LGT8F328. That MCU isn't supported by the OSHW firmwares (only ATmega).

[madires]

I've in trouble with a TC1 tester (version with ATMEGA324PA)
...
Can someone explain how to flash the U1?

Please search the web for 'programming ATmega' and you'll find tons of tutorials.

[sanjeevjain]

My LCR TC1 tester always show zener diode on screen
Self Calibration  and IR function is working,  it battery got too much heated,

[madires]

IIRC, the modified firmware runs the Zener check after performing the normal probing. Possibly there's something wrong with the circuitry for the Zener check. Does the tester display the Zener voltage? Does it stay about the same or change wildly?

[littlebalup]

Hello guys,

I unfortunatly fried my T7 tester with an old cap... it blown the SRV05-4 and damaged the Atmel MCU (PA0 shorted to GND).
I'd like to repair it by replacing the Atmel chip. Now comes the question of flashing a new firmware. The original chip was bit locked so no way to dump it.
I tried the 1.55m with the settings I guessed was the more appropriated to my model (7.12. Multifunktionstester TC-1 or T7 newer variant with ATmega324, 16 MHz). It kind of work (screen) but the test button must constantly be pressed.

My model is the one distributed by jot-it : https://joy-it.net/files/files/Produkte/JT-LCR-T7/JT-LCR-T7_Manual_2023-09-21.pdf
The board is the same as this one with "FNIRSI-4A10" marking : https://www.eevblog.com/forum/testgear/tc1-lcr-meter-transistor-tester-fix/msg4349419/#msg4349419

I didn't found a matching schematic so I managed to create it to have a better view of what's going on: https://www.dropbox.com/scl/fi/nhep7nofblowvybj1coy1/joy-it-LCR-T7-FNIRSI-4A10-Schematic.pdf?rlkey=cwgv53vsnv0slwwttjkvneh8d&dl=1

It may be not 100% accurate. Specially I don't really understand how the test button is working in conjuction with Q1,Q2 and Q3. What is the role of U8. And the U6 and U7 circuitry looks weird compared of what I seen on other clone schematics.

So, please comment and give me some clues of the configuration I need for the firmware.

[indman]

https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg5369153/#msg5369153

[Proxy64]

Hi guys,
CH341A seems to be supported by avrdude,
but how to setup  in the Makefile, especially for options ?

# CH341A Programmer
PROGRAMMER = ch341a
PORT = /dev/tty.usbserial-1410  #(MacOs)
OPTIONS =   

Thank you

[madires]

So, please comment and give me some clues of the configuration I need for the firmware.

Have you tried the PASSIVE_POWER_CTRL option (in config.h)?

[indman]

So, please comment and give me some clues of the configuration I need for the firmware.

You can safely remove the STC chip, it is not needed for the work of the m-firmware and only interferes.
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg5332607/#msg5332607

[littlebalup]

Have you tried the PASSIVE_POWER_CTRL option (in config.h)?

Yes I tried both with and without. I probably messed up some pin assignments. I'll investigate.

https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg5369153/#msg5369153

Your 1.51m works but constantly in probing loop. Your provided config files will be helpfull anyway. Thank you.

You can safely remove the STC chip, it is not needed for the work of the m-firmware and only interferes.
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg5332607/#msg5332607

Ok so I'll remove it. I tested the 2hry's compiled firmware https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg5332478/#msg5332478
It seems to work fine. But is 1.51m. Any advantage to update to 1.55m?

[indman]

Your 1.51m works but constantly in probing loop.
Any advantage to update to 1.55m?

Read the m-firmware manual carefully from madires and then you will have less unnecessary questions!
The tester can work in continuous (cyclic) and manual start modes.

[littlebalup]

Read the m-firmware manual carefully from madires and then you will have less unnecessary questions!
The tester can work in continuous (cyclic) and manual start modes.

Yep. Sorry for the dumb questions that you probably answered a million time. The project is really dense and a bit intimidating but I will deep dive into it.
I already figured the feature with #define CYCLE_MAX.
The 1.55m seems to run ok now with the proper power control configuration...
I also figured out the memory space is very tight and fine tuning is necessary.

Anyway thank you both for your help and your amazing work.

[Proxy64]

Hi guys,
My LCR-TC1 has an LCD type Z180SN009 and a chip 324pa.
-GND
-VCC
-RES PB4
-A0 PB5
-SDA PB6
-SCK PB7

I saw several similar boards in this topic, but I can't find this screen in the config_644.h file!
Is it supported by Markus firmware?

[madires]

A quick search returns that it should be an ST7735 which is supported.