$20 LCR ESR Transistor checker project

[madires]

That's a strange issue! 1.35m works fine with my HD44780 based 16*2 text displays. Have you changed the default settings for the HD44780 driver?

[indman]

Hi,madires!
Did you see information on the new ATMega328 chip clone - LGT8F328P from LogicGreen Technologies https://www.electrodragon.com/w/images/b/b6/LGT8F88P_LGT8F168P_LGT8F328P_translated.pdf ?
Speed up to 32 MHz, ADC -12 bit, is an opportunity diff. inclusion of inputs and gain of an input signal in 8/16/32 times and there are a lot of other interesting opportunities.
Whether its use in a tester is possible? 

[madires]

That AVR clone has some interesting additional features! What I dislike is the that the EEPROM is shared with the flash for the 32kB type. 64kB or 128kB flash would be great.

[bitseeker]

Thanks, indman. Interesting µC. ED sells 5 for US$3.40.

[broadway]

Hi,madires!
Did you see information on the new ATMega328 chip clone - LGT8F328P from LogicGreen Technologies https://www.electrodragon.com/w/images/b/b6/LGT8F88P_LGT8F168P_LGT8F328P_translated.pdf ?
Speed up to 32 MHz, ADC -12 bit, is an opportunity diff. inclusion of inputs and gain of an input signal in 8/16/32 times and there are a lot of other interesting opportunities.
Whether its use in a tester is possible? 

The code in config328. Lines of other displays removed.

Code: [Select]

#define LCD_HD44780
#define LCD_TEXT                        /* character display */
#define LCD_PAR_4                       /* 4 bit parallel interface */
#define LCD_PORT         PORTD          /* port data register */
#define LCD_DDR          DDRD           /* port data direction register */
#define LCD_DB_STD                      /* use standard pins 0-3 for DB4-7 */
#define LCD_DB4          PD0            /* port pin used for DB4 */
#define LCD_DB5          PD1            /* port pin used for DB5 */
#define LCD_DB6          PD2            /* port pin used for DB6 */
#define LCD_DB7          PD3            /* port pin used for DB7 */
#define LCD_RS           PD4            /* port pin used for RS */
#define LCD_EN1          PD5            /* port pin used for E */
#define LCD_CHAR_X       16             /* characters per line */
#define LCD_CHAR_Y       2              /* number of lines */
#define FONT_HD44780_INT                /* internal 5x7 font: international */
//#define FONT_HD44780_CYR                /* internal 5x7 font: Cyrillic */
I'm getting these three screens at boot

[indman]

Thanks, indman. Interesting µC. ED sells 5 for US$3.40.

Is issued in the case QFP48L and QFP32L

[madires]

The code in config328. Lines of other displays removed.

I'm getting these three screens at boot

Looks like the default settings for the HD44780 display. And there's nothing wrong with the second screen. But "Vt Tester" is strange, unless you have changed the string in variables.h. Maybe a wonky signal line to the display? Connection issue?

[broadway]

I had to convert bitmaps/font_HD44780_cyr.h and bitmaps/font_HD44780_int.h to UTF8 to solve an error during the make all command(as stated here)

Other than that I don't think I changed anything significant. I reverted back to 1.34 and it works fine as usual.

[madires]

When FONT_HD44780_CYR isn't enabled the content of bitmaps/font_HD44780_cyr.h is ignored as the precompiler commands simply hide the variables. But I found a strange character at the beginning of bitmaps/font_HD44780_cyr.h and I removed it. Interestingly my compiler didn't complain about that.

[indman]

I compiled a firmware Markus of 1.35 English for HD44780 and checked its work in Proteus.
I did not receive any errors at compilation, everything works normally.
Also normally the firmware works with the Cyrillic HD44780_cyr.h font.
I put screenshots of the program.

[Andrey]

I want to apologize, the Russian font 16 font_8x16_cyrillic_vfp.h does not work, I fixed it, besides you need to add lines to the file ST7565R.c:
/ * fonts and symbols * /
/ * vertically aligned, vertical bit order flipped, bank-wise grouping * /
#include "font_8x8_vf.h"
#include "font_8x16_vfp.h"
#include "font_8x8_CYRILLIC_vf.h"
#include "font_8X16_CYRILLIC_vfp.h"
#include "symbols_24x24_vfp.h"
Checked on Hiland M644.
Dear madires, replace in your files.
Thank!

[stj]

Sorry for the newb question.

I have had 3 of these, 2 bought a year ago and I just had another delivered today, and none of them work with an external 9v power supply. If I hook up a battery clip and connect external power via the battery clip it works. I thought this might have been an assembly or design fault that may be fixed in later runs but it's there with the new unit also.

What's possibly going on here that an external power supply plugged directly in won't work? And how do I fix it.

This is the tester I have

https://www.ebay.com.au/itm/GM328A-Component-Tester-Multifunctional-Meter-Graphic-Transistor-Tester-W1/352521940684?hash=item5213f1eecc:g:zy8AAOSwGD1b9TKZ:rk:1:pf:1&frcectupt=true

for future reference, that board is NOT a GM328A, it's a clone of the AY-AT.
i dont know if it's the same colour display though.
you will need to know this if you want to change the firmware.

[salamangkero]

Hello. I made an account just for this little jampacked tool. i tried 1.35m firmware and my lcd went bonkers, so i tried to fix it i removed the x offset and changed font and contrast probably disabled a couple of more things since i don't have rotary encoder. still couldn't get it quite right, it keeps probing after i turn it on. I reverted back to 1.13k version in the end. Has anyone been able to make it work for this iteration of Component Tester? Please give me pointers on how to change the config328.h and config.h to match my tester. Thanks.

[madires]

Have you tried the settings for the T4 listed in the Clones file?

[salamangkero]

Hello madires, i have tried the settings on the Clones file. I finally got the LCD to work and set the autohold mode to default. I can't seem to find the setting to activate the menu with long press though.

Edit:

LOL! holding the underside of the switch brings out the menu after testing. i didn't know i have a capacitive encoder if there ever is such a thing. O_o

[indman]

Hi madires!
I want to ask about unclear to me results of measurements of resistance on m-firmware.
This effect affects not only fresh firmwares 1.35, but also older firmwares.
I measure resistor resistance 0.22 Ohms with an accuracy of 1% and sometimes I receive reliable result as on photos, and sometimes the result is underestimated up to 0.1 Ohms.
I checked AY-AT on the clone and also I observe the same effect at simulation in Proteus. I found that this error appears at measurement of resistance from 0.1 - 0.25 Ohms. How can you explain it?

[JoeO]

Hi madires!
I want to ask about unclear to me results of measurements of resistance on m-firmware.
This effect affects not only fresh firmwares 1.35, but also older firmwares.
I measure resistor resistance 0.22 Ohms with an accuracy of 1% and sometimes I receive reliable result as on photos, and sometimes the result is underestimated up to 0.1 Ohms.
I checked AY-AT on the clone and also I observe the same effect at simulation in Proteus. I found that this error appears at measurement of resistance from 0.1 - 0.25 Ohms. How can you explain it?

You are using different socket pins on the ZIF socket.

Your ZIF socket has been used a lot.  That does not help the situation.

[indman]

JoeO,ZIF a socket has no relation to this effect.
I wrote that I see the same error at simulation in Proteus. In Proteus there are no ZIF of sockets.

[madires]

Hello madires, i have tried the settings on the Clones file. I finally got the LCD to work and set the autohold mode to default. I can't seem to find the setting to activate the menu with long press though.

The menu is triggered by pressing the test push button twice or turning the rotary encoder anti-clockwise. It's explained in the README file.

[madires]

I want to ask about unclear to me results of measurements of resistance on m-firmware.
This effect affects not only fresh firmwares 1.35, but also older firmwares.
I measure resistor resistance 0.22 Ohms with an accuracy of 1% and sometimes I receive reliable result as on photos, and sometimes the result is underestimated up to 0.1 Ohms.
I checked AY-AT on the clone and also I observe the same effect at simulation in Proteus. I found that this error appears at measurement of resistance from 0.1 - 0.25 Ohms. How can you explain it?

When it's not a contact problem then I have no idea about the cause. I'll investigate that issue.

[salamangkero]

Thanks madires. I found another problem with this clone and it seems the LED gets pulled low when pressing the test button, i checked the schematic at page 9 of Ttester_eng111k and rewired it to ground and vcc with 220 ohm resistor and the problem went away. I'm now using 1.35m without any problems. I guess it's time to put together a case for this little widget. Thanks for the help, great community here.

[madires]

I want to ask about unclear to me results of measurements of resistance on m-firmware.
This effect affects not only fresh firmwares 1.35, but also older firmwares.
I measure resistor resistance 0.22 Ohms with an accuracy of 1% and sometimes I receive reliable result as on photos, and sometimes the result is underestimated up to 0.1 Ohms.
I checked AY-AT on the clone and also I observe the same effect at simulation in Proteus. I found that this error appears at measurement of resistance from 0.1 - 0.25 Ohms. How can you explain it?

When it's not a contact problem then I have no idea about the cause. I'll investigate that issue.

I've measured a 0.22 Ohms resistor with different testers several times and wasn't able to reproduce the issue. A few times I got slightly higher values caused by contact issues which were resolved by wiggling the leads.

[pleriche]

I have the EZM version of GM328 which I've had for several years and found very useful. Recently I got it out to demonstrate to a friend and it didn't work! Any sensible person would just go and buy another, but not me. How can I not fix it? The only thing I could think of which might have caused it was that I normally keep it in a little pouch with a 9v battery, which might have touched something it shouldn't. But given that the ATMEGA328P is a DIL chip in a socket and the screen still works there's nothing I couldn't fix.
(Pic of the board and schematic as I've traced it out attached.)

The problem is that it always says Bat Empty! even though it isn't. This seems to be because something on the board is draining around 100mA from Vcc to ground, pulling the input to the 5V regulator U2 down to 5.6V and the regulator output (Vcc) to 4.4V.

I've tested all 3 transistors and tested the voltage regulator by substitution. The resistor values of the voltage divider feeding PV5 (battery monitor ADC input) are good, as are the resistors on  the base of Q2 and the collector or Q3. I can see no solder bridges or dry joints and I've resoldered all the IC socket pins and a fair few others.

But if I pull the ATMEGA chip the current drain drops to a reasonable value for the LED and display backlight. If I burn my spare chip with the Arduino Blink program (driving the LED through PD6) it blinks nicely but I haven't succeeded in getting any of the Arduino ST7565 examples to run.

Early on I decided to suck the firmware out of the chip and burn another, but it seems to be read-protected. So I found the source online, built it for the ST7565 display and uploaded it to another chip. On about the 3rd attempt I got the display orientation correct but the heavy current drain is still there! I could easily believe on of the GPIO pins was shorting to ground but not that a fresh chip had the same fault!

Just for the moment I'm stuck. I was hoping that describing the problem and my steps so far would unblock my brain but as yet it hasn't. Can anyone help?

[timelessbeing]

Did you try disconnecting the display?

[Willem52]

Please, I would check the electrolytic capacitors...