Author Topic: $20 LCR ESR Transistor checker project  (Read 3408673 times)

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Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7900 on: October 03, 2022, 12:20:29 pm »
Would the auto-hold mode help (next probing cycle is triggered by a button press)?
 

Offline boneDragon

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Re: $20 LCR ESR Transistor checker project
« Reply #7901 on: October 03, 2022, 12:51:16 pm »
not always, sometimes its desirable to work in auto-restart mode (sorting of components, measuring of value change etc)...
simply don't clear whole screen, just rewrite element type/values

and somehow to disable TP2 pin probing, for false detections
(using resistor pullup/down on some pin, or in config)
« Last Edit: October 03, 2022, 01:03:01 pm by boneDragon »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7902 on: October 03, 2022, 02:18:11 pm »
Then maybe the 'monitor' functions?
 
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Offline boneDragon

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Re: $20 LCR ESR Transistor checker project
« Reply #7903 on: October 03, 2022, 03:37:18 pm »
thats it
is it possible to add to this diode/LED junction measurement, E24/E96 values with resistance continuity buzzer,
and make "monitor" as default mode on power-on, with working long-click for power-off, double-click for menu etc ?...
« Last Edit: October 03, 2022, 03:54:36 pm by boneDragon »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7904 on: October 03, 2022, 06:41:22 pm »
A diode/LED monitor shouldn't be too hard to add. The other features would screw up the UI concept and might be an idea for an alternative firmware.
 

Offline gipetto

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Re: $20 LCR ESR Transistor checker project
« Reply #7905 on: October 04, 2022, 01:07:48 pm »
I know the porting to a 3.3v mcu question gets asked a lot and shot down because 5v is superior, but i was thinking of how split transformers have a negative, 0v and positive output. some of the transistor testers use two 3.7v cells in series.
Could a pair of cells be tapped in the middle for 0v and run a pair of 3.3v mcu in a split rail setup. that way you could get 6.6v of range, superior to the 5v mcu.
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7906 on: October 04, 2022, 05:37:54 pm »
The reason for 5V is that more components can be detected than with 3.3V. Placing two 3.3V MCUs in series won't work because they will be exposed to voltages out of spec. One solution for using a 3.3V MCU is to add an external switching matrix plus ADC which make things more complex and expensive.
 
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Offline gipetto

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Re: $20 LCR ESR Transistor checker project
« Reply #7907 on: October 04, 2022, 06:20:29 pm »
Ah I see.
 

Offline jwperry

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Re: $20 LCR ESR Transistor checker project
« Reply #7908 on: October 07, 2022, 11:12:32 pm »
Hey guys, quite the thread!

So like many of you, I purchased a random tester off of ebay several years ago and noticed some limitations that might be rectified by better firmware. Going off of the clones folder, I believe I have a MK-328. I attempted to flash Karl-Heinz Kübbeler's firmware based off some instructions from a Russian blog, but sadly I don't speak Russian and might have messed up some fuse settings. In addition, I was unable to dump the original firmware prior to flashing as I believe the chip was set to not allow dumping. (I'm not super knowledgeable when it comes to this stuff). Anyway, I am attaching images showing the unit, the board, the original fuses and lock bit settings, and the output from avrdudess. As it stands, a single button press will turn the screen on and then eventually fade to black after about 10 seconds.
Any input would be appreciated
-John
« Last Edit: October 07, 2022, 11:27:13 pm by jwperry »
 

Online indman

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Re: $20 LCR ESR Transistor checker project
« Reply #7909 on: October 08, 2022, 08:22:02 am »
jwperry,try to fill in the firmware that I attached below.
Download the archive, unzip it to the root of the disk from your computer. There should be no long paths to the firmware source files, as you have shown in your screenshots.
Now the fuses - they should be like this
fuses_lo = 0xf7
fuses_hi = 0xd9
fuses_ext = 0xfc
lock_byte = 0xff
« Last Edit: October 08, 2022, 03:52:50 pm by indman »
 
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Offline jwperry

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Re: $20 LCR ESR Transistor checker project
« Reply #7910 on: October 08, 2022, 09:24:30 pm »
indman,
Thanks for getting back to me. I have updated and set the fuses and lock bit. I attempted flashing the firmware you shared with me and now I am getting strange characters on screen. This only happens once. If I pull the battery from the unit and reinstall then I get the same "fade to black" behavior. I have attached a photo of the unit and a screenshot of avrdudess when using your firmware. This was flashed from a short path. Thanks again
-John
 

Online indman

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Re: $20 LCR ESR Transistor checker project
« Reply #7911 on: October 09, 2022, 08:22:03 am »
Try 2 more firmware versions from the archive that I attached.The fuses are exactly the same as I wrote before. What will be on the display in this case?
 

Offline Yuriy_K

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Re: $20 LCR ESR Transistor checker project
« Reply #7912 on: October 09, 2022, 08:40:13 am »
Question to users of my firmware. Do I need to include in the firmware ??? The memory of the ATmega 328 is at its limit.
Improved the measurement of single diodes. Expanded the measurement of the forward voltage drop with a measuring resistor of 470k (in the original texts at 680 Ohms). Here are measurement examples for various types of diodes ...
« Last Edit: October 09, 2022, 08:47:26 am by Yuriy_K »
 

Offline Maniaxx

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Re: $20 LCR ESR Transistor checker project
« Reply #7913 on: October 10, 2022, 08:30:32 pm »
Is there anything one should pay attention to when getting a GM328A from China? I read something from "old batches" or "round edges". I want to flash custom firmware and replace crystal (16MHz). Would this be a good pick? They call it 'new version'.
 

Offline jwperry

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Re: $20 LCR ESR Transistor checker project
« Reply #7914 on: October 10, 2022, 09:58:05 pm »
indman,
We are starting to get somewhere. Both versions boot and allow for testing of components. I just using a 4700uf 35v cap for testing purposes. However there is still some interesting behavior from the tester. I can test components with the Chinese NoStripe firmware but the display font is very dim.  On the third firmware the font takes a second to "warm up" but is eventually bold and legible.  Also the third firmware keeps requesting calibration which I attempted. I can test a component with the third firmware and I receive values but it does ask for calibration each time. I may need to read the documentation on how to properely calibrate. I would start wondering about components on the board or the display itself, however, when flashing the first firmware you provided (with the odd characters), the font is is completely fine.

Breakdown:
First Firmware: Bold, legible odd characters
ChineseNoStripe: Faded hard to read, tests components successfully
Third Firmware: Screen looks mostly fine. Tests components successfully, but might have some calibration issues

Thank you for your efforts so far sir!

-John
 

Offline Yuriy_K

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Re: $20 LCR ESR Transistor checker project
« Reply #7915 on: October 11, 2022, 07:23:43 am »
I want to flash custom firmware and replace crystal (16MHz). Would this be a good pick? They call it 'new version'.
If this clone has a BGR gamma display, it cannot run at 16 MHz. See page 277 for details.

For "k" firmware corrected the measurement of Darlington transistors. Source and pictures are attached. The source requires more memory, check for exceeding the limit.
« Last Edit: October 23, 2022, 07:55:24 am by Yuriy_K »
 
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Online indman

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Re: $20 LCR ESR Transistor checker project
« Reply #7916 on: October 24, 2022, 05:55:16 pm »
For "k" firmware corrected the measurement of Darlington transistors.
What are the markings on the transistors you showed in the screenshots?
 

Offline Yuriy_K

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Re: $20 LCR ESR Transistor checker project
« Reply #7917 on: October 25, 2022, 03:51:34 am »
What are the markings on the transistors you showed in the screenshots?
These are NPN transistors - KT972B, PNP - 2SB1093 - datasheet on the previous page.

New firmware, taking into account previously published changes.
« Last Edit: October 25, 2022, 07:09:34 am by Yuriy_K »
 
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Offline vever001

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Re: $20 LCR ESR Transistor checker project
« Reply #7918 on: October 26, 2022, 01:00:53 am »
Hello everyone, and thank you for this great project!

I'm attempting to update my "Daniu" TC-1 clone with an atmega324pa.
I did not make any hardware modifications yet (no 10uF cap, no mod).
The v1.34m hex from the Yandex repo works fine https://disk.yandex.ru/d/yW8xa5NJgUo5z/LCR-%D0%A2%D0%A11/Firmware/Markus%20Reschke/English/16MHz

I'm now trying to compile the latest v1.47m but all I get is a white screen and I need to unplug the battery.
Here are the changes I made from the original v1.47m: https://github.com/vever001/Transistortester-Warehouse/compare/39cf8f2adc5921e460891bf5707916381a2d36cf...vever001:Transistortester-Warehouse:master
You can also check my commits here: https://github.com/vever001/Transistortester-Warehouse/commits/master

I don't know what's wrong... I tried to replicate the exact config from the yandex repo.
Can anyone spot the issue? or give any hints?

Thank you very much  :),
Hervé
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7919 on: October 26, 2022, 08:42:32 am »
Have you tried the settings listed in the Clones file?
 

Offline vever001

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Re: $20 LCR ESR Transistor checker project
« Reply #7920 on: October 26, 2022, 11:19:21 am »
Ok I started again from scratch, applied the clones instructions and it works perfectly now... Sorry for that :palm:
Here's my config if anyone wants it (for a Daniu TC-1 with atmega324pa): https://github.com/vever001/Transistortester-Warehouse/commits/clones-settings

I made some more changes:
- flip the LCD X and Y (screen was upside down)
- remove the LCD offsets (pixel lines were showing up at the edge)
- use 8x16 cyrillic font (some chars were not showing properly)
- enabled UI_AUTOHOLD (for convenience)

Now I can start digging in the options and hardware mods :)

Thank you for the amazing work,
Hervé
 

Online indman

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Re: $20 LCR ESR Transistor checker project
« Reply #7921 on: October 29, 2022, 08:37:26 am »
New! :)
Updated the comparison table of clones  - added 2 devices on fake microcontroller and a clone on LGT8F328.
Be careful when choosing a device to purchase from Chinese friends!  ;)
« Last Edit: October 29, 2022, 08:40:52 am by indman »
 
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Offline MaxFrister

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Re: $20 LCR ESR Transistor checker project
« Reply #7922 on: October 29, 2022, 03:59:57 pm »
I bought a T7 ("LCR-T7(2)"?) recently to try. It appears to mostly work except for zener testing.

For low voltage zeners, it seems to test but test high.

For high voltage (>20V) zeners, it seems to power them as soon as connected even before test button is pressed.  Reports results but high.  However the zeners are hotter than the sun after removed.

Before I open the case and void my warranty ;-) I wanted to check that this is not  the expected behavior.
« Last Edit: October 29, 2022, 04:11:51 pm by MaxFrister »
 
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Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7923 on: October 29, 2022, 04:29:36 pm »
IIRC, the boost converter of the TC-1, T7 and the other models with the same case is running as long as the tester is powered on.
 

Online indman

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Re: $20 LCR ESR Transistor checker project
« Reply #7924 on: October 29, 2022, 05:16:35 pm »
MaxFrister,In all TC clones, the current in the tested zener diode is limited by a resistor of a certain value in units of milliamps(no more than 5mA). If the zener diode being tested is very hot, this means that a more significant current flows through it, which can damage it.This is a malfunction!Open a dispute with the seller, unless of course you somehow shorted the K-A contacts between each other or with one of the test contacts 1-2-3.Then you are the culprit of the malfunction.

 I also have a suspicion that you have a clone inside with a fake processor. You are no longer the 1st who complains about the heating of the tested zener diode.I think this malfunction is caused by a serious error in the circuitry of Chinese engineers. ;)
« Last Edit: October 29, 2022, 05:51:34 pm by indman »
 
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