In my pics, there is a big difference in ESR measuring between the original firmware (8.19 ohm) and the m firmware (0.14 ohm). And the ESR results of m firmware and DE-5000 are nearly equal.
In my pics, there is a big difference in ESR measuring between the original firmware (8.19 ohm) and the m firmware (0.14 ohm). And the ESR results of m firmware and DE-5000 are nearly equal.Regarding Transistor Testers with their original Chinese factory firmware:
It is always necessary to "short the probes" and then press "Start" to perform the "self-test" before expecting accurate test results. Chinese firmware performs "self-test" for 15 to 60 seconds and then displays a message instructing the user to "isolate probes" (remove the short) and then the self-test continues for another 20 to 60 seconds before it finishes. Unlike open-source Transistor Tester firmware the Chinese firmware does not display intermediate "step-by-step" data screens during self-test. It may be necessary to perform "self-test" several times before getting accurate test results.
Many Transistor Testers with Chinese firmware are capable of selecting either English or Mandarin for the displayed language. This is (of course) desirable for Transistor Testers which are sold both inside Chinese-speaking countries and exported. For example I have an LCR-TC1 unit (MCU is LGT8F328P) where holding down "Start" button for 5 to 10 seconds changes the displayed language between English and Chinese characters.
Because Chinese display fonts occupy a substantial amount of flash, the Chinese software developers must remove large portions of the original Transistor tester code and/or greatly simplify it.
This most certainly impacts their accuracy and reduces their feature sets.
Have you calibrated the component tester before and after flashing the OSHW firmware? and again when alternating between the ZIF socket and the test leads? This is an important step to do every time to change the environment.
In this Chinese firmware, it looks like self-calibration has been cut off. I have tried many times, but only this result appears
Please measure resistance of each 680 ohm probe resistor. There are 3 of these, each connected between a MCU pin and a test socket pin.
Have you checked for continuity between all the #1 test pins?
I have the same item like this. Mod to Atmega328 with 1.48m firmware. Here is the result:
In this Chinese firmware, it looks like self-calibration has been cut off. I have tried many times, but only this result appearsPlease measure resistance of each 680 ohm probe resistor. There are 3 of these, each connected between a MCU pin and a test socket pin.
These 3 resistors must match each other within +/- 1 ohm.
I had a similar issue with a “kit” style Transistor Tester where the 3 resistors supplied with the kit measured as follows: 675, 676, 691 ohms. The resistor which measured 691 ohms was far enough out of range to prevent my tester from entering “self test” mode. Instead, when powered up with 1-2-3 shorted it would only display the following test result: “1 - [resistor] - 2 - [resistor] - 3”
Details in my earlier post:
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4726172/#msg4726172
I have the same item like this. Mod to Atmega328 with 1.48m firmware. Here is the result:
Can you provide details on how you modded to replace this mcu with the ATMEGA328?
Luke
FREQ = 16
#define HW_REF25
#define ZENER_R1 100000
#define ZENER_R2 10000
#define ZENER_UNSWITCHED
#define ZENER_BOOST_HIGH /* high active */
#define HW_PROBE_ZENER
#define ZENER_VOLTAGE_MAX 20000 /* max. voltage in mV */
#define HW_IR_RECEIVER
#define UI_ZENER_DIODE
#define BAT_DIRECT
#define BAT_OFFSET 0
#define BAT_WEAK 3600
#define BAT_LOW 3400
#define ADC_LARGE_BUFFER_CAP
/*
* ST7735
* - 4 wire SPI interface using bit-bang SPI
*/
#define LCD_RES PD1 /* port pin used for /RESX (optional) */
//#define LCD_CS PD5 /* port pin used for /CSX (optional) */
#define LCD_DC PD2 /* port pin used for D/CX */
#define LCD_SCL PD4 /* port pin used for SCL */
#define LCD_SDA PD3 /* port pin used for SDA */
#define LCD_FLIP_X /* enable horizontal flip */
//#define LCD_FLIP_Y /* enable vertical flip */
#define LCD_LATE_ON /* turn on LCD after clearing it */
#define TP_REF PC5 /* test pin for 2.5V reference and relay */
#define TP_BAT PC4 /* test pin for battery */
#define TEST_BUTTON PD5 /* test/start push button (low active) */
#define IR_DATA PD0 /* data signal */
#define BOOST_CTRL PD7 /* control pin */
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).
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.
... 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
]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.
Any suggestions regarding resetting the fuses would be welcomeAnother 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.
I have the same item like this. Mod to Atmega328 with 1.48m firmware. Here is the result:
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?
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.