$20 LCR ESR Transistor checker project

[madires]

Nope, TC1 doesn't show V_GSoff or anything close. For the m-firmware please see https://github.com/madires/Transistortester-Warehouse/tree/master/Firmware/m-firmware.

[indman]

Some JFET-MOSFETs are not detected correctly by k-firmware, but are successfully detected by m-firmware.

Here is an example of how JFET-N J201 detection differs on k-firmware and m-firmware 

[dazz]

I have madires' code compiled already with the added flag to flip the display, going to flash it now. Thanks, guys!

[dazz]

I have an issue with the display contrast, it's too high. I went to the menu and it was set to 22, but I don't know how to lower it, just kept increasing hoping it would cycle back to zero and up again, but it didn't. Also tried adding the CFLAGS += -DVOLUME_VALUE=10 flag to the makefile, but it seems to ignore it completely. Sorry to be such a pest, but can you guys please give me some pointers to fix this?

Using this: avrdude -p m328p -P usb -c usbasp -U flash:w:ComponentTester.hex -U eeprom:w:ComponentTester.eep

[madires]

From the README:

You can adjust the contrast for some graphic LCD modules. A short key press
increases the value and and a long key press decreases it. Two short key
presses will exit the tool. With a rotary encoder installed the value
can also be adjusted by turning the encoder.

To change the default value check out LCD_CONTRAST in config_328.h.

[dazz]

Got it working! It's now measuring my mmbfj201's, and the values for Idss and Vgsoff are almost identical to the ones I measured manually yesterday. Great stuff guys, vielen danke!

[dazz]

I'm still having a couple minor issues. The text in the display is shifted a little bit (see picture attached). I checked the flags in the documentation but couldn't find an obvious one to try, any ideas, please?

The second issue is, I added the POWER_OFF flag to the Makefile, but the tester keeps probing on a loop. Here's what I got in WinAVR, I added the last two compiler flags, and it compiles without error, not sure what I'm doing wrong.

Code: [Select]

# compiler flags
CC = avr-gcc
CPP = avr-g++
CFLAGS = -mmcu=${MCU} -Wall -I. -Ibitmaps
CFLAGS += -DF_CPU=${FREQ}000000UL
CFLAGS += -DOSC_STARTUP=${OSC_STARTUP}
CFLAGS += -gdwarf-2 -std=gnu99 -Os -mcall-prologues
CFLAGS += -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums
#CFLAGS += -flto
CFLAGS += -MD -MP -MT $(*F).o -MF dep/$(@F).d
CFLAGS += -DLCD_ST7565_V_FLIP=1
CFLAGS += -DPOWER_OFF
EDIT: Wait a minute, I commented out both those flags I added, compiled, flashed... and it made no difference. Looks like it's ignoring them completely.

[madires]

For the m-firmware edit config.h and config_328.h, as explained in the README. And don't add random flags to the Makefile! The shift of the display is caused by LCD_OFFSET_X (config_328.h). Simply comment it out. For probing cycles see CYCLE_DELAY, CYCLE_MAX and POWER_OFF_TIMEOUT (config.h).

[dazz]

For the m-firmware edit config.h and config_328.h, as explained in the README. And don't add random flags to the Makefile! The shift of the display is caused by LCD_OFFSET_X (config_328.h). Simply comment it out. For probing cycles see CYCLE_DELAY, CYCLE_MAX and POWER_OFF_TIMEOUT (config.h).

Oh, by README I thought you meant the pdf documentation. Sorry about that, got it now.

[indman]

This is an important difference for compiling k-firmware and m-firmware I think will be very useful for many people to know:
In the k-firmware all the basic settings before compiling are made by editing the file "Makefile". In the m-firmware the global settings are concentrated in 3 files: "Makefile", "config.h" and "config_<mcu>.h

[dazz]

All is good now, thanks guys. 

[madires]

The RTFM hint is really nice! I think I should add it as a default option, mabye UI_RTFM?

[indman]

The RTFM hint is really nice! I think I should add it as a default option, mabye UI_RTFM?

I also suggest that the RTFM be placed on the start page as well as in the "DATA" section

[RoGeorge]

Maybe make that an option, not the default.

Such a warning will become annoying from day one.  Will also defeat the whole idea of this instrument.  This instrument stands out exactly because it needs zero training.  Connect something and whatever you throw at it, the instrument does the rest.

[dazz]

I vote for slapping the entire README in a "welcome" screen and force the user to scroll down the whole thing before getting a reading. 

[indman]

Maybe make that an option, not the default.

Don't take my post above too seriously. Pay attention to the emoticons.

[elecdonia]

elecdonia,I think you may back edit your post regarding ATmega324 and its support in k-firmware.

I am very eager to get LCR-TC2 containing either ATmega324 or ATmega644. So far I received one unit with LGT8F328P and another with APT32F172K8T6. So a week ago I ordered a third unit described by vendor as LCR-TC2.

Great news: I received the LCR-TC2 today. It contains ATmega324. I don’t have photos to post yet, but I did confirm the PC board looks exactly like the PC board in this post:
     https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4639780/#msg4639780

My plan is to replace the ATmega324 with ATmega644. However I think I will try out the -k and -m firmware for ATmega324 first, before upgrading the MCU.

[vever001]

Hi everyone,

I have a TC-1 model. Everytime I want to use my tester the battery is flat 
I'll probably make the recommended TC-1 mod from https://github.com/madires/Transistortester-Warehouse/blob/master/Hardware/TC1-Mod.kicad.tgz to prevent the battery getting drained.
But I would also like to change the tiny litium cell in it for 1 or 2 standard 18650 cells.
I will also probably design and 3D print a suitable case for it.

Now I see the lithium cell has a BMS.
If I go with a single 18650, can I reuse the existing BMS?
Can I safely wire two 18650 cells in parallel each having their own BMS?
If so what kind of BMS should I choose?
Do I really have to use BMSes in the first place or is it just for safety?

Thank you

[elecdonia]

Hi everyone, I have a TC-1 model. Everytime I want to use my tester the battery is flat 

There may be something in the hardware which stays on all the time even when display is off.

Please measure the current flow from the battery to the PC board for both the operating state (display on) and the sleep state (after display turns off) and post the results.

Also please post photos of the PC board.
Several different manufacturers are now producing LCR-TCx units. So far I have identified 3 totally different circuit designs:
   1) LCR-TC1 with APT32F172K8T6 MCU, 32-pin TQFP square package. This is same size package as ATmega328. But totally different pinout.
   2) LCR-TC1 with LGT8F328P MCU. Also 32-pin TQFP. Pinout is different than ATmega328, also different than APT32F172K8T6.
   3) LCR-TC2 with ATmega324 MCU, 44-pin TQFP package. I think older LCR-TC1 units (2021 and before) also contained ATmega324 MCU.

So far all of my LCR-TC1 (or -TC2) units hold a battery charge for several weeks or more. I will endeavor to measure their battery currents and post the results.

[vever001]

Wasn't the issue already identified by those who created the TC1-mod? Which is supposed to fix this exact issue I believe.
Right now I'm running the alternative firmware for the U4 chip https://github.com/atar-axis/tc1-u4

I have the version with ATmega324PA, so circuit design n°3 that you described.
I'll measure the current draw when I have some time.

[RoGeorge]

Everytime I want to use my tester the battery is flat

Mine has the same 9V alkaline battery since 2015.  The instrument is used rather rare, but the battery was connected all this time.  Battery is less than half now.  There is no mechanical switch.  The instrument goes to standby by itself, at a few seconds after each measurement. 

[masterdums]

Hello. Can you share the project in Proteus?

[Feliciano]

Hi everyone, I have a TC-1 model. Everytime I want to use my tester the battery is flat 

There may be something in the hardware which stays on all the time even when display is off.

If we're talking about an unmodified old version of the TC-1, that's a known issue. If you dig into the messages of june 2018 of this thread, you will find recommendations for replacing the U3 (or U4) that draws some idle current (with the screen off), replace it with a new power management circuit, and flash the m-firmware (don't forget to set the fuses too).

Or if you have one of the new non-Atmega versions, maybe you need to check the battery itself (and the new shipped batteries are tiny).

I think older LCR-TC1 units (2021 and before) also contained ATmega324 MCU.

Also the old versions of the T7. For more details, you can consult the Table of Clones.

[vever001]

Indeed, this was my understanding.
I plan to replace U4 with the TC-1 mod but I would also like to use 18650 batteries since the current battery is tiny.

My main questions was about the BMS and possibly wiring 2 18650 in parallel.

[indman]

My main questions was about the BMS and possibly wiring 2 18650 in parallel.

Why attach an 18650 and a BMS module if you can use a 2600mAh battery and forget about the power supply problem?
This battery fits perfectly in the TC-1 case.