$20 LCR ESR Transistor checker project

[indman]

Has somebody succeded on remaping some ports of a damaged MCU?

No, it is better not to waste your precious time on these experiments, and immediately throw such a controller in the trash. This will save you from possible problems and unexpected results in the operation of the device. That's my opinion and a wealth of experience.

[madires]

I haven't tried that yet. Suprisingly I never managed to damage an ATmega all these years. Anyway, two or three users have remapped ADC pins (also cut traces and so on) after damaging one, and it seems to work fine for them. Personally I agree with indman. You never know what else is damaged by the overvoltage. If you can't replace the ATmega for some reason remapping might be worth a try.

[Feliciano]

Note: I also have been lucky of not damaging one CTester yet, knock on wood. My mistake was to sell ALL the ATmegas I showed to my friends/customers

The thing would it be to find an original m328p these days, and the cost/risk of finding it overseas and bringing it here. That's the only reason for considering to workaround this convenient Wei-M8-Shell. For sure it would be (literally) a black box of potential surprises, but hey, just for the sake of it, I already remaped PC0 to PC3. The benefit was a reasonable response time, but now instead of a Cell it detects a MOS, so maybe there's more internal damage, and I don't notice any another apparent B or C spare port on the schematic. Anyways, I realize the change is not as easy as replacing the port on the config.h, as now the usual 1-3 menu entries show 4-3 instead, and the final step of the adjustment asks for a capacitor between 2-3, so something else would be needed to be modded on the config, and I don't know whether it would be related with the MUX0, MUX1 that is referred there (and I haven't tracked that to other parts of the k-firmware code):

Code: [Select]

#else /* PROCESSOR_TYP */
//############### default for mega8, mega168 and mega328
 #define ADC_PORT PORTC
 #define ADC_DDR DDRC
 #define ADC_PIN PINC
 #define TP1 PC3
 #define TP2 PC1
 #define TP3 PC2
 // Port pin for external Voltage measurement (zener voltage extension) PC3
 #define TPext ((1<<MUX1) | (1<<MUX0))
 // Port pin for 2.5V precision reference used for VCC check (optional) PC4
 #define TPREF (1<<MUX2)
 #define TPRELAY PC4
 // Port pin for Battery voltage measuring PC5
 #define TPBAT PC5 /* identical to ((1<<MUX2) | (1<<MUX0)) */
 // option WITH_VEXT can be set automatically, if WITH_UART is unset
 #define TPCAP -1
#endif /* PROCESSOR_TYP */


[Gengis]

I'll do the homework and come back with the results

I'm back just to confirm that my tester's black screen was caused by my not writing the .eep file into the microcontroller's eeprom.

Thank you again

[rogerdammit]

Ah, got it. Here are the values I get:
T2: 13 18 23
T3: -44 -88 -49

These results are poor, especially in the T3 test. The results in tests T2-T3 should be close to 0 and not differ from each other by more than 5 units. Check the values ​​of the measuring resistors 680 Ohm and 470 kOhm.
You can compare the results of your tests with similar tests of other participants on page 369.
You also need to remove all the conductors that you connected for the ICSP interface and repeat selftest!

No idea what happened but I picked up my tester after a week and suddenly all the issues are gone.  Calibrates properly and the open circuit high capacitance issue is gone.

Wasn’t looking forward to resoldering all the connections so happy it fixed itself. Thanks for the help!

[tonedeak99]

Hi what a great thread. Im just a hobbyist looking for an esr meter for capacitors. Mostly in circuit. Would you recommend one of the many clones such as the LCR-Tx’s?  I loved inman’s clone comparison chart.  Any features that are important to look for?

 I cant afford a nicer DER D-5000 or peak atlas meters. Just want an affordable way to see if caps are bad and need replacing. Probably mostly power supply caps and audio amp caps.

Thanks!

[madires]

There are better options for low-cost in-circuit ESR checking, e.g. https://www.eevblog.com/forum/projects/5-transistor-esr-meter-design/.

[indman]

I cant afford a nicer DER D-5000 or peak atlas meters. Just want an affordable way to see if caps are bad and need replacing. Probably mostly power supply caps and audio amp caps.

I advise you to take a closer look at this model of smart tweezers MS8911 - it is relatively inexpensive and will easily perform the tasks you need. 

[tonedeak99]

Thank you both. As for the smd tweezers I seem to run into more thru hole caps than smds. But they seem pretty fantastic. Ill keep those in mind if I need an smd cap tester in the future.

[Feliciano]

Question to the group:
According to your experience, and given the difficulty of finding an original one, which of the non-ATmegas is better or worse? LGT8F328 or APT32F172K8T6? (perhaps considering the typical firmware variation found for each one, as we know there are better adaptations than others).

[indman]

Feliciano, is your question not quite clear to me? The LGT8F328 can be easily replaced by the ATMega328 as it is almost identical in pinout.
APT32F172K8T6 cannot be replaced by anything and there is no working firmware for it!

[Feliciano]

I know, but I mean: if you don't have an ATmega unit or IC spare on your drawer, and you would have to compromise with one of the knock-off, to be used "as is". Which one would you pick, or which to avoid the most? Currently, I could buy either one (of the two), to be pass to a friend.

In fact, I read some old post of yours with a list of limitations, but I don't know which one has more handycaps than the other.

[indman]

Currently, I could buy either one (of the two), to be pass to a friend.

Is that a real good friend? If so, then why make such a disgusting gift that has a lot of flaws from the start?
Is it such a big problem to find a GM328A c DIP ATMega328 variant or TQFP factor now?
If you still have to pick one shit out of two possible, it better be LGT8F328.

[Feliciano]

I'm exploring the options, the costs, and the wait time. Thanks for the answer.

[indman]

I'm exploring the options, the costs, and the wait time.

I'm sure you'll make the right choice, good luck!

[Feliciano]

Another question: what is the maximum Symbol size that we could use for a 160x128 display? According to the config is 32x32, and I read here that 32x39 is not meant for that resolution, so I wonder whether it would worth to develop something in the middle, like 32x35
(note: my current font size is 8x16. Has one to be an exact multiple of the other?).

[madires]

For practical reasons the symbol size should be a multiple of the font size to match the probe numbers and their positioning. Otherwise you would get unpleasing gaps between symbol and probe numbers. Another important point is that some display controllers address the Y axis via 8-bit pages, i.e. you can only address the page and not specific rows. And we can't use a display buffer because the ATmega328's RAM is too small for this. So the height of fonts and symbols needs to be a multiple of 8 for those controllers.

[madires]

After surviving the April's Fool Day here's the real deal. Get your programmer ready and enjoy!

v1.52m
- Added quick-check tool for diodes and LEDs (SW_DIODE_LED).
- Support for BH1750VFI ambient light sensor (HW_BH1750).
- Fixed protocol issue for addressing chips in read mode in function I2C_WriteByte() for bit-bang I2C.
- Fixed scaling error in the voltage divider calculation in T2 of the Self Test function.
- Option for packed output format of font display for test purposes (FONT_PACKED).
- Added new font font_8x16_alt_hf.h (FONT_8x16_ALT_HF, thanks to Feliciano@EEVblog).
- Corrected bitmap for O umlaut in font_8x16_iso8859-2_hf.h (thanks to Feliciano@EEVblog).
- Fixed data byte issue in I2C_ReadByte() for hardware TWI (reported by fail@mikrocontroller.net).
- Corrected the colors for 0.1 and 0.01 multipliers in Display_ColorCode() (reported by chaoslegion@VRTP).
- Option to switch temporarily to auto-hold mode after a component is found (in continuous mode, UI_AUTOHOLD_FOUND, suggested by Maniaxx@EEVBlog).
- Added option to optimize the interrupt vector table to reduce firmware size (Makefile: OPTIMIZE_VECTORS, thanks to Viktor Klimkovich).
- Improved UJT detection to exclude potentiometers with a specifc resistance (3-15 k) and the wiper turned to one end (reported by wandows@EEVblog).
- Fixed issue with return value in DataStorage() (thanks to Viktor Klimkovich).
- Fixed detection issue of small capacitances which was caused by the newly added negative zero offset in LargeCap() (reported by Yuriy_K@EEVblog and Obelix2007@EEVblog).

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

[Adrian_Arg.]

Hello people, would someone be so kind as to make a video of the configuration and compilation steps, since I have a gm328, and I would like to update it

[indman]

madires ,thank you for adding very important clarifications to points T1-T6 selftest in the README! I think it would also be useful to add one more important point to this HINTS point in README:
"- Long test leads have a negative impact and worsen the values in T2, T3, T5 and T6."
- Disconnect all ICSP interface conductors - they significantly affect the selftest(adjusting) procedure and also interfere with the normal operation of the tester!

[carl1961]

Hello people, would someone be so kind as to make a video of the configuration and compilation steps, since I have a gm328, and I would like to update it

There is different ways, depending on what computer your using.

I learned a lot for this video   

this is how I did it on my Window 11, but should be same as for windows 10

https://github.com/carl1961/Transistor-Tester-AVR-Compiled-files-On-Windows

[Adrian_Arg.]

Thanks, I'll see if I can do it, with the last few attempts it's stuck.

[Kim Christensen]

Thanks, I'll see if I can do it, with the last few attempts it's stuck.

Don't forget that you must upload both the EEP and the HEX file. Uploading just the HEX file can cause it to malfunction.

[Adrian_Arg.]

Thanks, I already installed virtualbox and Ubuntu, I followed the steps at https://github.com/carl1961/Transistor-Tester-AVR-Compiled-files-On-Windows
  Now I have to see what files are modified for my GM328, like the one in the video

[Yuriy_K]

After surviving the April's Fool Day here's the real deal. Get your programmer ready and enjoy!

Why did you block diode mapping in JFET transistors? "Protective diodes are limited, but they do occur. I had to restore the existing solution myself.