$20 LCR ESR Transistor checker project

[hapless]

I removed, cleaned and reinstalled the 8MHz crystal, but the white screen fault returns.  I will order a 8MHz and a 16MHz crystal as I may want to experiment with 16MHz firmware and new versions of the firmware.  Thank you very much for your help and advice.  It is very much appreciated!   

Check the screen pinout connection match with the new firmware pin connections

Check the screen pinout connection match with the new firmware screen pin connections settings

As well as clock speed and rotation, and offset and feature set... if you're the one compiling the firmware 

ayubando, this forum allows you to edit your own posts, so no need to double-post to make corrections.

[Yuriy_K]

For this display, a flashing with a change in font orientation. At the request of the Russian version ...

Replaced the archive with the firmware based on the results of debugging

[kiltro]

Hi everyone!
Is this still possibile to find this Hiland M644 version? (I'm in Europe)
Are there any newer versions?

Thanks

[snapper]

sold out everywhere, maybe available at banggood from the beginning of august !

https://de.banggood.com/Original-Hiland-M644-Transistor-Tester-LCR-Diode-Transistor-Zener-Quartz-Measurement-p-1279042.html

[madires]

If you want to run the m-firmware with an NT7538 based display (ST7565 compatible) the reset timing needs to be adapted in function LCD_Init() in ST7565R.c:

Code: [Select]

  #ifdef LCD_RESET
    /* reset display */
      /* long reset for NT7538 (10µs/1µs) */
      /* trigger reset */
      LCD_PORT &= ~(1 << LCD_RESET);         /* set /RES low */
      wait20us();                            /* wait 20µs */
      LCD_PORT |= (1 << LCD_RESET);          /* set /RES high */
      /* wait for controller to perform reset */
      wait2us();                             /* wait 2µs */
  #endif

The next firmware version will have a setting to enable the long reset needed for the NT7538.

[supercap]

Hi all!
Sorry for my poor English...

I prototyped the tester with one breadboard, Arduino Mega 2560 why I want to learn how work the software (version 1.49m).
I'm using Visual Studio Code and PlatformIO.

I corrected all setting (hope so) in config.h file.
I put too, the right values on #define R_LOW and R_HIGH. matching the real resistor values.

I did the Self Test and I had this values:
T1 Vref 1176mV
T1 Vref 1176mV
T1 Vref 1177mV
T1 Vref 1177mV
T1 Vref 1177mV
T2 +Rl- 12 13 23 13 18 18
T2 +Rl- 12 13 23 13 17 18
T2 +Rl- 12 13 23 13 18 18
T2 +Rl- 12 13 23 13 17 18
T2 +Rl- 12 13 23 13 18 18
T3 +Rh- 12 13 23 -2 -9 2
T3 +Rh- 12 13 23 -2 -9 2
T3 +Rh- 12 13 23 4 -11 -4
T3 +Rh- 12 13 23 -11 3 -8
T3 +Rh- 12 13 23 1 -13 -1
T3 +Rh- 12 13 23 -6 2 -13
T5 Rh- 0 0 0
T5 Rh- 0 0 0
T5 Rh- 0 0 0
T5 Rh- 0 0 0
T5 Rh- 0 0 0
T6 Rh+ 4995 4992 4995
T6 Rh+ 4993 4996 4990
T6 Rh+ 4994 4994 4996
T6 Rh+ 4992 4996 4992
T6 Rh+ 4993 4994 4996

I measured few times a film capacitor like instructions.

Self Adjustment values and first problem:

A2 R0 12 13 23 109 109 175
A2 R0 12 13 23 109 110 175
A2 R0 12 13 23 109 110 175
A2 R0 12 13 23 111 110 174
A2 R0 12 13 23 109 110 176
A2 R0 12 13 23 111 108 176
A4 Ri- 27 27 27
A4 Ri- 27 27 28
A4 Ri- 27 27 27
A4 Ri- 27 27 28
A4 Ri- 27 27 27
A5 Ri+ 132 133 134
A5 Ri+ 132 133 134
A5 Ri+ 132 133 134
A5 Ri+ 132 133 134
A5 Ri+ 132 133 134
A6 C0 12 13 23 54 51 54
A6 C0 12 13 23 54 51 54
A6 C0 12 13 23 54 51 54
A6 C0 12 13 23 54 51 54
A6 C0 12 13 23 54 51 54

Ri- 3,7 Ohm
Ri+ 18,4 Ohm
C0 53 pF
R0 0,20 Ohm
Vref 1191mV
Vcc 5001mV
AComp -8mV

Now when I push the button appear the message "Error!"
I push again the button and the tester return on menu.

I tried to test some resistors and I get wrong values:
Resistor Value | Tester Value | Real Value
100                   49,7              97
148                   72                 149
470                   477               475
560                   556               555
4,7 K                 11,8 K           4,61K
6,8 K                 17,2 K           6,71K
100 K                48 K              99K

The tester can recognize diodes, transistor, triac, ecc. with no problems.

Maybe I miss something setup when I was reading the manual of Markus Reschke?
 

[madires]

An Ri- of 3.7 Ohms is too low. There's something wrong. Have you enabled ADC_LARGE_BUFFER_CAP in config.h? The error message for the self-adjustment is caused by a too high R0 for probes #2 and #3 (A2 R0 12 13 23 109 109 175). The limit is 150 (1.5 Ohms for both in series).

[supercap]

An Ri- of 3.7 Ohms is too low. There's something wrong. Have you enabled ADC_LARGE_BUFFER_CAP in config.h? The error message for the self-adjustment is caused by a too high R0 for probes #2 and #3 (A2 R0 12 13 23 109 109 175). The limit is 150 (1.5 Ohms for both in series).

Thank you Madires for you very fast reply.
Tomorrow I will check for the ADC_LARGE_BUFFER_CAP option.
About pin resistances, I will try to change the wires with not crimped one. This because I have found some days ago, one wire with inusual resistance...

[supercap]

I enabled ADC_LARGE_BUFFER_CAP and changed wires, now resistor values are ok!
Still present some problems on "big" capacitors:
Value | Tester Value | Real Value  | Type

100uF    76,12           100,4           electrolytic
220uF    165,9           225,0           electrolytic
47uF      39,19           51,25           electrolytic
10nF      10,26           10,53           polyester
330nF    316,2           318              polyester
150pF    155pF           154              tantalum

Maybe I miss something again... 

I can find somewhere a schematic diagram of this tester with all functions with Mega 2560 controller?

I wanna use this post too for make my big compliments for the clean code written by Madires. You did a really big work.

[indman]

Maybe I miss something again...

Yes, here is the part of the madires manual that will help you

"* Capacitors

The measurement of capacitance is split into three methods. Large caps >47µF
are measured by the charging cycle method with 10ms pulses. Mid-sized
caps between 4.7µF and 47µF are processed the same way but with 1ms charging
pulses. And small caps are done by the analog comparator method. That
way the accuracy of the measurement of caps is optimized.

Large capacitances require a correction. Without correction the measured values
are too large. IMHO, that is caused by the measurement method, i.e. the ADC
conversion after each charging pulse needs some time and the cap looses charge
due to internal leakage during the same time. Also the ADC conversion itself
needs some charge to operate. So it takes longer to charge the cap, and the cap
seems to have a larger capacitance. A discharge measurement later on tries to
compensate this, but is able to do it just partially. The correction factors (
CAP_FACTOR_SMALL, CAP_FACTOR_MID and CAP_FACTOR_LARGE in config.c) are choosen
to work with most tester models. In some cases you might have to change them."

[supercap]

Maybe I miss something again...

Yes, here is the part of the madires manual that will help you

"* Capacitors

The measurement ...

Large capacitances require a correction. Without correction the measured values
are too large. IMHO, that is caused by the measurement method, i.e. the ADC
conversion after each charging pulse needs some time and the cap looses charge
due to internal leakage during the same time. Also the ADC conversion itself
needs some charge to operate. So it takes longer to charge the cap, and the cap
seems to have a larger capacitance. A discharge measurement later on tries to
compensate this, but is able to do it just partially. The correction factors (
CAP_FACTOR_SMALL, CAP_FACTOR_MID and CAP_FACTOR_LARGE in config.c) are choosen
to work with most tester models. In some cases you might have to change them."

Thank you indman!
Yes I read this, but there is write "Without correction the measured values
are too large". In my case, I have small values not large one.
For this I was think about some other problems...

[indman]

Yes I read this, but there is write "Without correction the measured values
are too large". In my case, I have small values not large one.

You have a ARDUINO MEGA2560 and you have enabled the ADC_LARGE_BUFFER_CAP option, so you will need to correct capacitance readings on various bands anyway.

"CAP_FACTOR_SMALL, CAP_FACTOR_MID and CAP_FACTOR_LARGE in config.c"

Madires, there is a small error in Readme - instead of config.c, config.h is meant.

[supercap]

Thank you indman, with a little setup on CAP_FACTOR_LARGE option I resolved this problem too.
Now last problem...
If I try to use DATA_EEPROM for store data in EEPROM, my tester don't work.
My display appear empty, after some second appear the text "2: 5v".
Is like the firmware cant store the data in the right mode...
If i double press the button for enter in menu, appear ":", then the moving pointer "*".
Is like the text are not stored in EEPROM?

[hapless]

Are you flashing both the program file and the EEPROM file or just the program? You need both.

Also, check the MCU speed in the makefile. If it says "FREQ = 16" and your crystal is 8MHz, you will have wrong measurements no matter what else you try.

[TankedThomas]

I just got a T7 with what I believe is an LGT8F328 (QFP32L) and was wondering if someone can please help me with reprogramming it.
Since there's the WIP firmware for this chip, I was going to give that a try, but since it doesn't use ISP, I have no idea how to connect it to a programmer.

I soldered a 5-pin header onto the board but haven't managed to get neither Arduino nor AVRDUDE to read it.
I probably have the pinout wrong but it's hard to find any specifics about what to connect where in order to dump and flash the chip (assuming that's possible).

I'm using a Raspberry Pi because it's the most convenient, though I have a regular USBasp 2x3P connector as well, and some Arduino-compatible boards if necessary (Teensy 2.0++ and ESP8266).
If someone can please point me in the right direction, that'd be really helpful. I couldn't find anyone else trying to do this, though this thread is pretty large so I haven't read every single post (yet).
Maybe replacing it with the Atmega328p is a better idea but I'm not sure if it's worthwhile.

[indman]

Since there's the WIP firmware for this chip

What firmware, which is tested and fully functional, are you going to program into the LGT8F328 chip?
My advice - do not waste your time, but change the chip to a classic ATMega328, for which there are author's working firmware.

[elecdonia]

Since there's the WIP firmware for this chip

What firmware, which is tested and fully functional, are you going to program into the LGT8F328 chip?
My advice - do not waste your time, but change the chip to a classic ATMega328, for which there are author's working firmware.

I agree with indman. At this point in time I think it will be far easier to replace the LGT8F328 with an Atmel ATmega328P. The required PC board modification is relatively simple.

I obtained a quantity of LGT8F328 "Arduino compatible" boards. These boards resemble the Arduino Pro-mini. They come with a bootloader installed and are programmed with a standard USB-TTL adaptor. I was curious to see what they are like. So far I succeeded at programming them after installing the LGT8F328 "boards" package into the Arduino IDE. These boards will run many standard Arduino sketches (such as "blink").

But I think it will still require considerable time and effort to modify existing Transistor Tester software for the LGT8F328.     

[supercap]

Are you flashing both the program file and the EEPROM file or just the program? You need both.

Also, check the MCU speed in the makefile. If it says "FREQ = 16" and your crystal is 8MHz, you will have wrong measurements no matter what else you try.

Hi hapless,
I do not compile the program with the makefile.
I'm using Visual Studio Core and PlatformIO and to be honest is hard for me understand why I have to flash EEPROM too: the program store the data in EEPROM with the files var_italian.h, variables.h.

[Yuriy_K]

I do not compile the program with the makefile.

You are creating problems for yourself. Here are my programs for writing code in arduino mega 2560...

[madires]

I'm using Visual Studio Core and PlatformIO and to be honest is hard for me understand why I have to flash EEPROM too: the program store the data in EEPROM with the files var_italian.h, variables.h.

The text/strings can change between versions (rarely tables and other data). It will also vary with the featues enabled/disabled. And compilers can rearrange data (we don't use fixed addressing).

[supercap]

You are creating problems for yourself. Here are my programs for writing code in arduino mega 2560...

I think not, why PlatformIO and his debug is the best way for me to learn how the program work.

[supercap]

The text/strings can change between versions (rarely tables and other data). It will also vary with the featues enabled/disabled. And compilers can rearrange data (we don't use fixed addressing).

Hmm, yes I start to think about some problem with compilator...
When I have time I will try to debug step by step and check the memory for find the problem.

[supercap]

I resolved my problem with DATA_EEPROM option.
The user hapless give me a input.
Some days ago PlatformIO released a new version.
So I found in Project tasks a function to upload the EEPROM too.
I tried and all was work fine.
I really appreciate your all help!
Thak you.

Last question, is there some way to make the LCD refresh more faster?

[madires]

If you are already using hardware SPI with the 16MHz Mega2560 you could try a display with a parallel bus.

[hapless]

Something slightly different...
https://dragaosemchama.com/en/2019/04/gm328a-reverse-engineering-new-firmware-and-tetris/

I tried the Tetris game, and it works well enough, but the piezo speaker got ripped out of the PWM output early on for sanity's sake.