$20 LCR ESR Transistor checker project

[gipetto]

my jt lcr t7 jumps around resistance measurements also 3.3kohm resistor
3278
3286
3290
3290
3289
3286

I have calibrated it with the sorted 3 pin wire but i can't find the procedure i recall reading about how to calibrate it with a capacitor. i've searched through the ttester.pdf

[madires]

There was a need to measure megaohm resistors, and noticed a nuance. It immediately shows, for example, 4470k, and then at first faster, and then it grows more slowly ... after a minute, about 4495k ... if you wait even longer from about 2 minutes, it can grow to 4497k ... and stops.
Interested in the question: is this normal for measurements? if so, is it really necessary to measure large resistances for 2 minutes? Or is it some kind of accumulation in the controller (or a failure ... although everything else measures correctly ...)? When can a measurement be considered more or less correct? At the very end or when it starts to "slow down"?
[...]
Tester G328A(BGR), firmware 1.13 color(from Yuriy_K).

From Karl-Heinz' documentation for the k-firmware:

If the ATmega has more than 8 KByte flash memory, the voltage measurement at the resistors will be delayed until no more changes are detected or the time limit is reached. With this method big capacitors are no more detected as resistors by mistake and the DC resistance of big inductors will be measured correctly.

I'd guess, an unstable Vcc (5V) could trigger that feature too.

[Obelix2007]

... calibrated it with the shorted 3 pin wire but i can't find the procedure i recall reading about how to calibrate it with a capacitor. i've searched through the ttester.pdf

... you can find it at page 40, capter 3.3 Selftest and Calibration.

Regards

Horst

[gipetto]

I've read that already. I think my firmware does not have the WITH Samplin-
gADC = 1 enabled in the makefile. thanks anyway

[richtoy]

Hi,

I have one of these cheap testers and decided to spend a rainy afternoon attempting a firmware update 

The version of the device I have is LCR-TC1 with original 2.12k firmware; a ATMEGA324PA version with 16MHz crystal with exactly this schematic  https://www.eevblog.com/forum/oshw/chinese-tc1-transistor-tester/?action=dlattach;attach=1355798;image

So from reading I see that I first need to update the firmware in U4, the STC15L104W.  The first thing I noticed is that the TX & RX are reversed in the P1 & P2 connections.  In the original schematic U4 pin 5 (tx) goes to P2 and pin 6 (rx) goes to P1 whereas is the schematic above they are reversed!

I downloaded the latest stc-isp (V6.91K) and eventually managed to update the firmware using the method described with the addition of the holding the button on the device down whist power is applied to force the 15L104 into boot mode.

Checking target MCU ...
  MCU type: STC15L104W
  F/W version: 7.2.5Q

Current H/W Option:
  . Current system clock source is internal IRC oscillator
  . Current frequency: 11.051MHz
  . Wakeup Timer frequency: 27.089KHz
  . Do not detect the level of P3.2 and P3.3 next download
  . Power-on reset, use the extra power-on delay
  . RESET pin behaves as IO pin
  . Reset while detect a Low-Voltage
  . Thresh voltage level of the built-in LVD : 2.42 V
  . Inhibit EEPROM operation under Low-Voltage
  . Hardware do not enable Watch-Dog-Timer
  . Watch-Dog-Timer pre-scalar : 256
  . Watch-Dog-Timer stop count in idle mode
  . Program can modify the Watch-Dog-Timer scalar
  . Do not erase user EEPROM area at next download
  . Do not control 485 at next download
  . Do not check user password next download
  . TXD is independent IO
  . TXD pin as quasi-bidirectional mode after reset
  . P3.3 output HIGH level after reset
  . Reference voltage: 1231 mV (Range: 1150~1320mV)
  . Testing time: 2017-9-28

  MCU type: STC15L104W
  F/W version: 7.2.5Q

Adjusting frequency ...         [1.031"]
Adjusted frequency: 12.011MHz (0.090%)

Re-handshaking ... Successful         [0.141"]
Current Baudrate: 38400
Erasing MCU flash ...  OK !      [0.359"]
Programming user code ... OK !      [1.375"]
Programming OPTIONS ... OK !      [0.063"]

H/W Option upgrade to:
  . Current system clock source is internal IRC oscillator
  . Current frequency: 12.011MHz
  . Do not detect the level of P3.2 and P3.3 next download
  . Power-on reset, use the extra power-on delay
  . RESET pin behaves as IO pin
  . Reset while detect a Low-Voltage
  . Thresh voltage level of the built-in LVD : 2.42 V
  . Inhibit EEPROM operation under Low-Voltage
  . Hardware do not enable Watch-Dog-Timer
  . Watch-Dog-Timer pre-scalar : 256
  . Watch-Dog-Timer stop count in idle mode
  . Program can modify the Watch-Dog-Timer scalar
  . Do not erase user EEPROM area at next download
  . Do not control 485 at next download
  . Do not check user password next download
  . TXD is independent IO
  . TXD pin as quasi-bidirectional mode after reset
  . P3.3 output HIGH level after reset
  . Reference voltage: 1231 mV (Range: 1150~1320mV)
  . Testing time: 2017-9-28
MCU ID : F2D400EC18041F

  MCU type: STC15L104W
  F/W version: 7.2.5Q

  . Set frequency: 12.000MHz
  . Adjusted frequency: 12.011MHz
  . Trim error: 0.090%


  Complete !(2023-04-12 17:49:36)

However, after successful flashing of the STC15L104W the tester no longer works.  It turns on as far as the title bar "M-Tester" but does nothing else and will not turn off!  Is this normal?

My intention is to build the full firmware on a RPi using the options that between lines 534-667 of the Clones.txt file in the firmware folder.  Has anyone done this?  Any pitfalls?

What is the procedure for flashing the main firmware?  Is the connection made via the U4 bit with EN shorted as power is applied to get the ATMEGA324PA into the correct mode?

[madires]

That's to be expected without the OSHW firmware. The 'main' firmware is programmed via the ATmega's ISP interface using an ISP programmer, e.g. USBasp or Arduino with the ISP sketch.

[elecdonia]

]In this Chinese firmware, it looks like self-calibration has been cut off. I have tried many times, but only this result appears

I have read your post before. Those resistors in my kit are good: 680, 680, 680.01.

I looked inside my Transistor Tester clone which contains same LGT8F328P MCU as yours.

Edit: Sorry, I was looking at wrong photo. Your LGT8F328P unit does have same PC board as my unit

 However my unit has a totally different PC board (photo attached).

All of my Transistor Testers with Chinese firmware go straight into "self test" immediately after powering up with 1-2-3 shorted. This differs from OSHW firmware where "Start" button must be pressed a second time to enter self-test.

I intend to rework my LGT8F328P unit for ATmega328P with the instructions you provided. Thanks! 

[oitar]

Any suggestions regarding resetting the fuses would be welcome

Another method for recovering a bricked AVR is using an external clock/oscillator. I did a quick search and found these:

https://www.eevblog.com/forum/beginners/bricked-atmega-1284-with-avrdude!-can-it-be-saved/
https://www.avrfreaks.net/s/topic/a5C3l000000UMBiEAO/t099084
https://www.avrfreaks.net/s/topic/a5C3l000000UboeEAC/t159156
https://classbproject.com/fixes-and-hacks/recovering-a-bricked-avr/

Connected it to an external 1 Mhz source(arduino), the mega324PA even has 125.0 kHz coming out of its PB1 pin. Running avrdudess with -b 1200 -B 56 (16 kHz SCK). Still unable to read signature, or change fuses.

Yes, I got it... Unbricking the avr(smd, 44 pin mega324PA) in-circuit is possible. Luckily most of the needed pins are present on the J7 header(H7 plus 2.1 board). Had to unsolder the onboard 10 kOhm reset resistor(to avoid frying the cpu with the 12 V). Also unsoldered the 6 pin display board(quite unnecessary I think), used arduino as prommer, and plenty jump-wires on abreadboard.
Don't want to clog the forum, but if someone needs it will provide step-by-step. Currently playing with the 1.48m.

[dirtmover]

I have the same item like this. Mod to Atmega328 with 1.48m firmware. Here is the result:

Got the exact same device delivered last week, T7-PLUS-V2 with V3.1E FW . Only found this discussion a couple of days ago, wish I'd have found it before ordering.

So far noticed the capacitor esr, inductance and zener breakdown voltage is quite a bit off

Can you point me to some details of this mod.

[elecdonia]

Got same device delivered last week, T7-PLUS-V2 with V3.1E FW . So far noticed the capacitor esr, inductance and zener breakdown voltage is quite a bit off

Does the PC board in your unit look exactly like either of my 2 attachments? Tan board or blue board?

Note that both units in my photos have 32-pin MCU (8 pins per side). Also there is a 16MHz crystal connected to the MCU. In both of my photos the MCU is “Logic Green” LGT8F328P.

I am asking because more companies are manufacturing Transistor Testers all the time. I’m trying to stay current with all the different variations which people are receiving.

[dirtmover]

Does the PC board in your unit look exactly like either of my 2 attachments? Tan board or blue board?

This is mine, looks the same as your tan one

[hoangtran]

I have the same item like this. Mod to Atmega328 with 1.48m firmware. Here is the result:

Got the exact same device delivered last week, T7-PLUS-V2 with V3.1E FW . Only found this discussion a couple of days ago, wish I'd have found it before ordering.

So far noticed the capacitor esr, inductance and zener breakdown voltage is quite a bit off

Can you point me to some details of this mod.

I shared here in this post: https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4804496/#msg4804496

[alex_D]

I bought a brand new ATMega644P, when I program it for the first time with a 20Mhz external crystal what fuse settings do I need to use?

This is what I used for ATMega328p

avrdude -c usbasp -p m328p -B 12.0 -e -U flash:w:"ComponentTester.hex":i -U eeprom:w:"ComponentTester.eep":i -U lfuse:w:0xF7:m -U hfuse:w:0xD9:m -U efuse:w:0x04:m

[madires]

Those fuse bit settings work for the ATmega644 too. But please change the efuse to 0xfc and ignore avrdude's warning about it (known issue, mistake in avrdude's config file).

[.RC.]

Edit: Found the issue.   Needed to install Winavr as windows was missing some bits. But it still did not make an eeprom file of a cfg file.


I have built my AYAT model with precision resistors, 0.1% voltage regulator and a 16mhz crystal, and need firmware. Well all I need is to change the clock from 8Mhz to 16MHz

Is there any way to use the makefile to output a .hex and .eep with windows 10 or is it linux only?

I downloaded the full 1.42m files just to see if I could output the hex files, and when I use the make command using the mingw program all I get is a heap of error messages. Which from prior experience seems par for the course when trying to do this with Windows.

C:\transtester>make
The system cannot find the path specified.
avr-gcc -mmcu=atmega328 -Wall -I. -Ibitmaps -DF_CPU=16000000UL -DOSC_STARTUP=16384 -gdwarf-2 -std=gnu99 -Os -mcall-prologues -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -MD -MP -MT main.o -MF dep/main.o.d -c main.c
process_begin: CreateProcess(NULL, avr-gcc -mmcu=atmega328 -Wall -I. -Ibitmaps -DF_CPU=16000000UL -DOSC_STARTUP=16384 -gdwarf-2 -std=gnu99 -Os -mcall-prologues -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -MD -MP -MT main.o -MF dep/main.o.d -c main.c, ...) failed.
make (e=2): The system cannot find the file specified.
Makefile:209: recipe for target 'main.o' failed
make: *** [main.o] Error 2

[.RC.]

Obligatory photo's.  My soldering is a bit ordinary.  I am still relearning that skill.

[oitar]

Hi all,
I'm encountering a peculiar problem that was there with the original firmware, and also showing with the 1.48m. T7-plus v1.1 board, mega324pa with the 27V voltage source(no transformer).
If I measure higher voltage zeners, it displays correct. For lower values- below 10V, it displays way lower- i.e. 3-4 times lower(but the voltage drop over the zener while measuring is correct).
I cannot perform calibration(having issues with the single button- only working to start, but no redo), but I think this has nothing to do with [RC] calibration?
Where can I manually touch the calculation?
The zener resistors were checked(100k and 12k), the voltage references are ok too.

These -afaik, are just to define the "working range", out of which the part is declared "not a zener"
#define ZENER_VOLTAGE_MIN     1000      /* min. voltage in mV */
#define ZENER_VOLTAGE_MAX     24000     /* max. voltage in mV */

And fiddling with these(which are correct):
#define ZENER_DIVIDER_CUSTOM
#define ZENER_R1         100000
#define ZENER_R2         12000
Only makes things worse. Is there an off-set I am not aware of?

[gipetto]

Maybe this is a silly idea but if anyone wanted to fix the situation with the clone mcu then one way would be to clone the clone testers, but with a second footprint for a dip or smt mcu. it wouldn't be much more expensive for manufacturers to build, and if someone wanted to upgrade, they could cut the traces to the logic green and drop in their mcu and crystal.
If they open sourced the design, then there would be a standard sellers would follow for more sales, same way as how the ay-at is the best seller now.

[madires]

I cannot perform calibration(having issues with the single button- only working to start, but no redo), but I think this has nothing to do with [RC] calibration?

Press the button twice to enter the menu. This and the self-adjustment process is explained in the README file.   

[.RC.]

Is there a dummies guide on how to compile the firmware, now I see 1.49m  just got released a few minutes ago. I am not sure what the flashlight is all about.

[madires]

Is there any way to use the makefile to output a .hex and .eep with windows 10 or is it linux only?

Please see https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/2475/

[madires]

Get your ISP programmer ready!

v1.49m:
- Alternative pinouts for IR receiver module (SW_IR_RX_PINOUT_G_V_D, SW_IR_RX_PINOUT_D_G_V, SW_IR_RX_PINOUT_D_V_G, suggested by boleslaw_43@mikrocontroller.net).
- Fixed capacitor detection issue in ESR tool. Happened after a semiconductor was found before by normal probing (reported by indman@EEVblog).
- Fixed bug in configuration management for touchscreens.
- Added check for frequency counter options to config_support.h.
- Moved code for counter tools from tools_signal.c to new tools_counter.c.
- Added checks for SPI_PIN and SPI_MISO to config_support.h in case bit-bang SPI with read support is enabled. Also extended SPI section in all
  config_<MCU>.h for easier handling.
- SW_R_TRIMMER shows now also the ratio of the second resistor (suggested by wandows@EEVblog).
- Display OneWire device symbol in DS18B20, DS18S20 and DHTXX tool (UI_ONEWIRE, suggested by indman@EEVblog).
- Added symbol for OneWire devices to all symbol sets (thanks to indman@EEVblog).
- Support for temperature sensor DS18S20 (SW_DS18S20, DS18S20_HIGHRES, suggested by indman@EEVblog).
- Added checks for Darlington BJTs to CheckProbes() & CheckDepletionModeFET() to prevent false detection as JFET in case EMI issues cause a high leakage current (reported by wandows@EEVblog).
- Fixed bug in check for Germanium PNP BJTs in CheckDepletionModeFET().
- Added configuration switch for sequential COM pin layout to OLED drivers for SH1106 and SSD1306 (LCD_COM_SEQ), and a switch for reversed COM mapping to the SSD1306 driver (LCD_COM_REMAP, suggested by boneDragon@EEVblog).
- Added support for a passive buzzer (BUZZER_ACTIVE or BUZZER_PASSIVE, suggested by boneDragon@EEVblog).
- Texts in Brazilian Portuguese (thanks to wandows@EEVblog).
- Added general purpose switched output, e.g. for an LED flashlight (HW_FLASHLIGHT, suggested by boneDragon@EEVblog).

Please download at
- https://github.com/madires/Transistortester-Warehouse/tree/master/Firmware/m-firmware
- https://github.com/kubi48/TransistorTester-source/tree/master/Markus

[madires]

now I see 1.49m  just got released a few minutes ago. I am not sure what the flashlight is all about.

It's a simple switched output controlled via the menu, e.g. for switching an LED (hence the name). Even smartphones have a flashlight app.

[.RC.]

Is there any way to use the makefile to output a .hex and .eep with windows 10 or is it linux only?

Please see https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/2475/

Thanks.  Some of the links are dead but I managed to find the avr GNU8 toolchain from the microchip website.

I was still getting an error message as the eeprom was not getting made.   But the solution is here

I will have to research ans configure the firmware for my device.  My first attempt has given me a white screen and that is all. But at least I can compile and upload it now.

[pepe10000]

Thanks madires.

Attached update of the Spanish language file for those interested.

All the best.