$20 LCR ESR Transistor checker project

[indman]

Did I buy the wrong screen or something?

Yes, this display is working, but it is different from the one that was damaged.

EDIT: Something else seems wonky. Now I need to keep the button pressed, or else the screen goes blank

You need to connect the backlight LED to avoid this effect

[dazz]

Did I buy the wrong screen or something?

Yes, this display is working, but it is different from the one that was damaged.

EDIT: Something else seems wonky. Now I need to keep the button pressed, or else the screen goes blank

You need to connect the backlight LED to avoid this effect

OK, thanks again. I think I'm going to get me a new meter and be done with it. Damn it...

[dazz]

OK, I've decided to try and flash a modified version of the firmware to fix the orientation of the text, then I'll run wires from the pcb to the flex cable and fix that in place with hot glue.

Is this the part of the code in lcd-routines.c that needs tweaking to mirror the display?

Code: [Select]

volume = eeprom_read_byte(&EE_Volume_Value); // read Vop
   lcd_command(CMD_SET_VOP_UPPER | ((volume >> 5) & 0x07)); // set upper Vop
   lcd_command(CMD_SET_VOP_LOWER | (volume & 0x1f)); // set lower Vop
   lcd_command(CMD_SET_START_LINE | (LCD_ST7565_Y_START & 0x3f));       // Set the Start line 0
   lcd_command(CMD_SET_ALLPTS_NORMAL); // 0xa4 set display to normal
   lcd_command(CMD_SET_POWER_CONTROL | 4); // 0x28|4 Charge Pump ON
   lcd_command(CMD_SET_COM_REVERSE); // 0xc8
   lcd_command(CMD_SET_COM_NORMAL); // 0xc0 set normal Y orientation
   lcd_command(0xa1); // set MX, X orientation, is pad selectet!
   lcd_command(0xaa); // set horizontal mode
   lcd_command(0xac); // set initial row
   lcd_command(0x08); // initial row = 8  (0-7)
   lcd_clear();
   lcd_command(CMD_DISPLAY_ON); // 0xaf Display on
   lcd_set_cursor(0,0);

[dazz]

I already have WinAVR installed, and it seems to compile the code and generate the hex and eep files just fine. I guess I just need to figure out how to mirror the screen, and I also need to flip the screen 180º. Or I think so.

Using this repo for the source, not sure if that's the right one. Any pointers are appreciated.

[elecdonia]

They look the same to me, have a look:

And now take a close look and compare how the cable should be soldered on the same clone as yours. You turned the cable over.

WTF? I reversed the cable orientation (and I don't know how a would mount it that way) and it works, but the text is all flipped horizontally. What gives? Was the screen not properly assembled or something? I'll try to get a picture, but I need extra hands for that

This same type of thing has happened to me: Although frustrating and time consuming, I prefer to think of these events as “learning experiences.” One new habit I’ve developed is to take plenty of photos before and during the disassembly process.
Also not every LCD screen of similar dimensions and specs has its flex cable oriented the same way. I’ve run into this myself.

[indman]

OK, I've decided to try and flash a modified version of the firmware to fix the orientation of the text, then I'll run wires from the pcb to the flex cable and fix that in place with hot glue.
Is this the part of the code in lcd-routines.c that needs tweaking to mirror the display?

No, you don't need to delve so deeply into the code to correct the orientation of the image.
All the necessary settings that you need to configure are in the Makefile file from the folder "mega328_T4_v2_st7565":

# If LCD_ST7565 option is set to 1: Flip the display's horizontal direction.
#CFLAGS += -DLCD_ST7565_H_FLIP=1
# With LCD_ST7565_H_OFFSET you can specify a horizontal pixel offset to the display window.
# The controller knows 132 horizontal pixel, the window shows only 128 pixel.
# OFFSET values can vary for the connected display type to 0, 2 or 4.
CFLAGS += -DLCD_ST7565_H_OFFSET=0
# If LCD_ST7565 option is set to 1: Flip the display's vertical direction
#CFLAGS += -DLCD_ST7565_V_FLIP=1

[dazz]

This same type of thing has happened to me: Although frustrating and time consuming, I prefer to think of these events as “learning experiences.” One new habit I’ve developed is to take plenty of photos before and during the disassembly process.
Also not every LCD screen of similar dimensions and specs has its flex cable oriented the same way. I’ve run into this myself.

You're 100% right. I'll be more disciplined from now on.

No, you don't need to delve so deeply into the code to correct the orientation of the image.
All the necessary settings that you need to configure are in the Makefile file from the folder "mega328_T4_v2_st7565":

# If LCD_ST7565 option is set to 1: Flip the display's horizontal direction.
#CFLAGS += -DLCD_ST7565_H_FLIP=1
# With LCD_ST7565_H_OFFSET you can specify a horizontal pixel offset to the display window.
# The controller knows 132 horizontal pixel, the window shows only 128 pixel.
# OFFSET values can vary for the connected display type to 0, 2 or 4.
CFLAGS += -DLCD_ST7565_H_OFFSET=0
# If LCD_ST7565 option is set to 1: Flip the display's vertical direction
#CFLAGS += -DLCD_ST7565_V_FLIP=1

Awesome! Thanks, I'll try that. Technically I just need to flip the display horizontally. The screen will be upside down, but I can always flip the whole device and use it that way, not a huge deal.

[MrSqueaky]

I received an LCR-TC2 from Aliexpress that I ordered in December 2022. The board appears to be updated. The boot screen says firmware is 3.1E and chip U3 seems to have been removed. No options for changing the power off delay (which is annoying short).

I previously had a round GM328A but the display driver was glitchy and wouldn't initialise properly half of the time. I managed to smash the display and couldn't easily source a replacement (I think it is a Samsung E1310/E1360/E1360M/B210/B220/B510 copy)

[dazz]

OK, I've decided to try and flash a modified version of the firmware to fix the orientation of the text, then I'll run wires from the pcb to the flex cable and fix that in place with hot glue.
Is this the part of the code in lcd-routines.c that needs tweaking to mirror the display?

No, you don't need to delve so deeply into the code to correct the orientation of the image.
All the necessary settings that you need to configure are in the Makefile file from the folder "mega328_T4_v2_st7565":

# If LCD_ST7565 option is set to 1: Flip the display's horizontal direction.
#CFLAGS += -DLCD_ST7565_H_FLIP=1
# With LCD_ST7565_H_OFFSET you can specify a horizontal pixel offset to the display window.
# The controller knows 132 horizontal pixel, the window shows only 128 pixel.
# OFFSET values can vary for the connected display type to 0, 2 or 4.
CFLAGS += -DLCD_ST7565_H_OFFSET=0
# If LCD_ST7565 option is set to 1: Flip the display's vertical direction
#CFLAGS += -DLCD_ST7565_V_FLIP=1

One more question, please. Is this the right repo? https://github.com/Mikrocontroller-net/transistortester
There hasn't been a commit there in one year

[indman]

https://github.com/Mikrocontroller-net/transistortester/tree/master/Software/trunk
Here is the current actual k-firmware distribution 07.10.2021

[dazz]

https://github.com/Mikrocontroller-net/transistortester/tree/master/Software/trunk
Here is the current actual k-firmware distribution 07.10.2021

Great, thanks. That's the one I was using 

[dazz]

Success! Thanks everyone for the help

[madires]

One more question, please. Is this the right repo? https://github.com/Mikrocontroller-net/transistortester
There hasn't been a commit there in one year

That's outdated (migration of mikrocontroller.net's SVN). Please use https://github.com/kubi48/TransistorTester-source!

[madires]

I received an LCR-TC2 from Aliexpress that I ordered in December 2022. The board appears to be updated. The boot screen says firmware is 3.1E and chip U3 seems to have been removed. No options for changing the power off delay (which is annoying short).

Haven't seen any schematics for that version yet, but without the additional control MCU it should be easier to upgrade to an OSHW firmware. And you could customize the user interface settings to your liking.

[dazz]

One more question, please. Is this the right repo? https://github.com/Mikrocontroller-net/transistortester
There hasn't been a commit there in one year

That's outdated (migration of mikrocontroller.net's SVN). Please use https://github.com/kubi48/TransistorTester-source!

Thanks. I was having issues with the calibration process, so I will use that instead 

[elecdonia]

…I was having issues with the calibration process, so I will use that instead.

With Transistor Testers that were previously in use, I go into the menu and select “Self Test” which works its way through several different screens, first with “probes shorted,” then with “probes isolated,” and finally with a film capacitor connected to pins 1-3. I use a 1.0uF capacitor for this. Don’t rush it by pressing the button to move on to the next screen. It will advance all by itself after each section finishes. I had to practice this several times before I was patient enough to wait and let it proceed at its own pace.

In particular it appears that capacitor ESR results are more accurate after performing this full menu-driven “self test” with the 1.0uF film capacitor connected to 1-3 when the display message calls for it.

I’ve also used the faster self-test with probes shorted before pressing power button. But this “fast self-test” by itself didn’t permanently shut off the “not calibrated” message. It was only after the longer self-test (from the menu) that the “not calibrated” message disappeared permanently.

I discovered this “not calibrated” issue with an unmodified “GM328 color-kit” tester running the original Chinese factory firmware it came with. This firmware displays “1.12k” but I suspect the Chinese modified it. Unfortunately its ATmega328P is locked.

Among several transistor testers in my workshop I use this one the most. I’ve had only one issue with it: I accidentally toasted its SRV05-4 overvoltage protector with a charged capacitor. The tester worked well again after removing the failed SRV05-4 except it began showing the “not calibrated” message. I observed no damage to the ATmega328P or any other parts. But I did need to run the full menu-driven self test after that incident in order to clear the “not calibrated” condition.

[elecdonia]

I received an LCR-TC2 from Aliexpress that I ordered in December 2022. The board appears to be updated. The boot screen says firmware is 3.1E and chip U3 seems to have been removed. No options for changing the power off delay (which is annoying short).

Haven't seen any schematics for that version yet, but without the additional control MCU it should be easier to upgrade to an OSHW firmware. And you could customize the user interface settings to your liking.

I’ve been trying to get my hands on one of these for 2 months. The first unit I received, labeled LCR-TC1, contained APT32F172K8T6 MCU. The 2nd unit, also labeled LCR-TC1, contained LGT8F328P MCU. I’m now awaiting unit #3, said to be model LCR-TC2.

My goal is to acquire a unit containing Atmel ATmega324 which I will then upgrade to ATmega644 along with adding the paddle switch on the side for menu access.

[elecdonia]

Note: 1. For all fuses “1” means unprogrammed while “0” means programmed.

With it programmed with 0xFF it sets all bits to "1" meaning unprogrammed, this means that the oscillator has a limited frequency range of 8 to 16MHz and startup mode: "slowly rising power" this is a low power operation mode for the crystal oscillator.
With it programmed with 0xF7 instead the CKSEL3 bit is progammed and this means that the crystal oscillator has a frequency range of 0.4 to 20MHz with the same starup mode as before, this is a higher power mode for the crystal oscillator.

I have an unmodified GM328A+ Transistor Tester, factory original v1.12k firmware, 8MHz, which fails to initialize its ST7565 monochrome LCD at startup when the room temperature is cold (10-15 C). But it starts up perfectly if I warm up the ATmega328 by holding my thumb over it for 20 seconds. This tester always works perfectly at normal room temperature. I plan to check the fuse bits to learn which oscillator settings are in it. Perhaps “low-power oscillator” mode starts up too slowly at very cold room temperature?

I own several Transistor Testers. The others work well at low temperatures. I’ll post what I find when I check this GM328A+ unit. I also intend to update it to current v1.13k.

[Feliciano]

IIRC "low power" xristal oscillator runs at 3.3V, and the "normal" or "full swing"are 5V. The ctesters I've seen have used normal oscillators, so I set the fuses accordingly.

[elecdonia]

Hello. Got 2 LCR Testers today from AliXpress..  New LCR-T4 and LCR-T7 Color. Both have new firmware version 3.12K 
Does anybody know where to find this firmware.. or is it a hoax..  mean Chinese Variants.. ? tnx for info JP

Would it be possible for forum members who recently purchased LCR- series Transistor Testers to post photos of their PC boards?

I’m asking because the Chinese manufacturers are now using 3 different MCU chips in current production LCR series Transistor Testers. Only one of these MCU chips is compatible with existing open-source -k or -m software. The other two MCU chips can use only proprietary software created by their Chinese manufacturers. That software cannot be updated or replaced by open-source Transistor Tester software.

At this time we can only determine which MCU is inside an LCR series Transistor tester by viewing a photo of the PC board. The model number, which could be LCR-TC1, LCR-TC2, LCR-T4, or LCR-T7, reveals nothing about what is inside. Often the vendors don’t even know what they are selling. They don’t post photos of the PC boards either.

Forum user indman maintains a table of clone versions of Transistor Tester hardware here:
     https://yadi.sk/d/yW8xa5NJgUo5z
The file name is TableClonesEn.pdf (or TableClonesRu.pdf)
However the large number of different Transistor Testers recently manufactured in China is on the verge of becoming a tsunami of randomness. Well-known model names such as LCR-TC1 or LCR-T4 are being applied to several entirely different hardware/software combinations. Some are incapable of running open-source -k and -m software. But the vendors don’t disclose this.

I recommend we should all pitch in and assist with separating the good and bad from the ugly. Photos of the PC boards will be a big help,

[MrSqueaky]

I received an LCR-TC2 from Aliexpress that I ordered in December 2022. The board appears to be updated. The boot screen says firmware is 3.1E and chip U3 seems to have been removed. No options for changing the power off delay (which is annoying short).

Haven't seen any schematics for that version yet, but without the additional control MCU it should be easier to upgrade to an OSHW firmware. And you could customize the user interface settings to your liking.

I've made a schematic the for LCR-TC2 T7-PLUS v1.2 I received. I also traced the tracks on the PCB in case I've made a mistake somewhere in the schematic. Ordered from this seller https://www.aliexpress.com/item/1005004717377243.html . I soldered on the battery connector. Hope this helps.

[madires]

IIRC "low power" xristal oscillator runs at 3.3V, and the "normal" or "full swing"are 5V. The ctesters I've seen have used normal oscillators, so I set the fuses accordingly.

low power oscillator:
- reduced voltage swing (no voltage given)
- can't drive other clock inputs
- more susceptible to noise
- low power consumption

full swing oscillator:
- rail-to-rail swing
- can drive other clock inputs
- less susceptible to noise
- power consumption higher than for low power oscillator

[madires]

[I've made a schematic the for LCR-TC2 T7-PLUS v1.2 I received. I also traced the tracks on the PCB in case I've made a mistake somewhere in the schematic.

Matches nearly the pin assignment of the TC1 (just without the additional control MCU). PD1 and PD2 are swapped (push button and power control) and the display pinout could be:

Code: [Select]

/RES   PB4
D/C    PB5
SCL    PB7
SDA    PB6


[indman]

PD1 and PD2 are swapped (push button and power control) and the display pinout could be:

Madires, for this clone variant your m-firmware as well as k-firmware(if ATMega644) is suitable.You only need to swap PD1 and PD2 in places. This has already been tested.

[madires]

Great! I'll add that one to the list of clone settings (Clones file).