$20 LCR ESR Transistor checker project

[indman]

madires, it works, thanks a lot!  I will still check the firmware on any device with ATMega324, but I am sure that it will work fine. Really, this issue was solved so easily and simply.I'm sorry I didn't figure it out sooner.I think you will be able to pass this amendment to Karl-Heinz so that he adds it to his distribution? 

elecdonia,I think you may back edit your post regarding ATmega324 and its support in k-firmware.

[elecdonia]

madires, it works, thanks a lot!  I will still check the firmware on any device with ATMega324, but I am sure that it will work fine. Really, this issue was solved so easily and simply.I'm sorry I didn't figure it out sooner.I think you will be able to pass this amendment to Karl-Heinz so that he adds it to his distribution? 
elecdonia,I think you may back edit your post regarding ATmega324 and its support in k-firmware.

Many thanks to both of you! 

I am always happy to see compiler finish its work with zero errors!
It just fits into flash size of ATmega324.

I am very eager to get LCR-TC2 containing either ATmega324 or ATmega644. So far I received one unit with LGT8F328P and another with APT32F172K8T6. Both were stated to be LCR-TC1 by ebay vendor. Unfortunately when I ordered those two units I did not think LCR-TC1 and LCR-TC2 were different from each other. So a week ago I ordered a third unit described by vendor as LCR-TC2. 

[indman]

So a week ago I ordered a third unit described by vendor as LCR-TC2.

I think and wish you that your 3rd order attempt was a success!

[indman]

madires,what does the name of the folder "experimentelle mega328_FA-BT2" in k-firmware imply?

[madires]

That's a tester kit sold by a German ham radio magazine (kit not sold anymore). You can find some pictures at http://dk8jg.de/ttest.htm.

[indman]

Wow! A rare copy of 10.2013.Beautiful! 

[techie]

Hi,

I was able to configure ComponentTester-1.48m firmware to work properly on a new LCR-TC2 v1.2 (T7 Plus v1.2 PCB) meter. Please see attached photo.
It lacks the STC15L104W chip found in the v1.0 and v1.1 PCBs, has a larger atmega644 MCU, and it swaps the test button and power enable pins.
In order to support 32x39 symbols, a minor edit to ST7735.c was required:

The line:
#include "symbols_32x39_hf.h"

should be added after:
#include "symbols_32x32_old_hf.h"

I've attached Markus v1.48m firmware binaries, along with the modified source files (colors.h, Makefile, config.h, config_644.h, and ST7735.c) needed for re-compiling  :

Hope this helps!

[RoGeorge]

I have this one with a firmware from around 2015, MTester V2.07, should I bother updating its firmware?
If yes, where from please, so to be compatible with this hardware version from 91make taobao?

[madires]

That one seems to be a T4. For k-firmware try mega328_T3_T4_st7565 or mega328_T4_v2_st7565, and for m-firmware see Clones file.

[RoGeorge]

Thank you.  Mine seems to be the LCR-T4 version, by looking at the pics here: https://www.mikrocontroller.net/topic/transistortester-avr?goto=4120737#4105488

On the previous page it says the current repository has now changed to kubi48, i.e.
https://github.com/kubi48/TransistorTester-source/tree/master/trunk/mega328_T4_v2_st7565

1. There are countless forks on github.  Which one should I use?
2. Can not find any log for what has changed from one firmware version to the other.  Is it worth to upgrade the firmware from 2015 to the most recent one?

[madires]

Karl-Heinz' repo (k-firmware) is https://github.com/kubi48/TransistorTester-source. Your tester runs a modified k-firmware, and AFAIK there's no recent changelog. However, the k-firmware version of 2015 should be 1.10k or 1.11k (latest one is 1.13k).

[dazz]

I'm back with a question, please. A friend of mine is testing jfets with a TC1, and I have the suspicion that his measurements are not Idss and Vgsoff. Here's a picture

I perused the manual, and it seems to me that's not really Idss and Vgsoff, is that correct? Could it be that his firmware was compiled with the FET_Idss flag disabled?
Are those values shown there the ones obtained with a 680 ohms source resistor, as per the manual?
My T4 with the latest firmware does seem to measure Idss and Vgsoff, plus an extra operating point in the middle. Did I get it right and that's what it's doing?

Actually, I have two questions. I also have a few MMBFJ201 and MMBF5457, and they are both detected as BJT's by my T4, while his TC1 does spit out a reading, what's the deal there, please?

[indman]

dazz
1. Please make the resolution of your photos smaller, attach them to the message or hide them under the spoiler. See how other forum members attach photos.
2. Install m-firmware for your T4 clone and test your transistors again.Compare your results with k-firmware.
3. Carefully calibrate your tester according to the author's manual.

[dazz]

dazz
1. Please make the resolution of your photos smaller, attach them to the message or hide them under the spoiler. See how other forum members attach photos.
2. Install m-firmware for your T4 clone and test your transistors again.Compare your results with k-firmware.
3. Carefully calibrate your tester according to the author's manual.

1. Sorry about that, fixed now.
2. I believe my T4 is at the latest version and it's calibrated. Got it from Kubi40's github repo a couple weeks ago. Is madires' the m-firmware you're referring to? Should I expect different results with that one?

[indman]

2. I believe my T4 is at the latest version and it's calibrated. Got it from Kubi40's github repo a couple weeks ago. Is madires' the m-firmware you're referring to? Should I expect different results with that one?

It is likely that there will be other results, which is why I suggested that you try the madires m-firmware.

[madires]

The TC1 shows just V_GS (and the corresponding current) with the JFET's gate pulled down via the 470k test resistor. Yes, the 680 Ohms resistor is used as current shunt. Can't say much more about the TC1's firmware as it is a modified k-firmware (fancy UI, less features, no source available). Your T4 shows I_DSS, V_GS with gate pulled down via 470k (plus current), and V_GSoff (current 0). The 'I=...@Vg=...' format is a compromise to have voltage and current in one text line.

[dazz]

2. I believe my T4 is at the latest version and it's calibrated. Got it from Kubi40's github repo a couple weeks ago. Is madires' the m-firmware you're referring to? Should I expect different results with that one?

It is likely that there will be other results, which is why I suggested that you try the madires m-firmware.

I'm looking for it. I need to recompile it to flip the display vertically, if you remember. But madire's repo is very different from kubi48's one. Is this it, please?
https://github.com/madires/Transistortester-Warehouse

Also, what about my friend's TC1? Will he get Idss and Vgsoff readings if he updates the firmware, or is that a limitation of that particular device?

[dazz]

The TC1 shows just V_GS (and the corresponding current) with the JFET's gate pulled down via the 470k test resistor. Yes, the 680 Ohms resistor is used as current shunt. Can't say much more about the TC1's firmware as it is a modified k-firmware (fancy UI, less features, no source available). Your T4 shows I_DSS, V_GS with gate pulled down via 470k (plus current), and V_GSoff (current 0). The 'I=...@Vg=...' format is a compromise to have voltage and current in one text line.

Oh, thanks for the info, that explains a lot. So no firmware upgrades for the TC1 then.
One thing I don't understand is, with a 470K source resistor, wouldn't that set the drain current very close to zero, hence measuring Vgsoff?

[indman]

Actually, I have two questions. I also have a few MMBFJ201 and MMBF5457, and they are both detected as BJT's by my T4, while his TC1 does spit out a reading, what's the deal there, please?

Some JFET-MOSFETs are not detected correctly by k-firmware, but are successfully detected by m-firmware.
I have experienced this effect many times. I also assume that Chinese firmware contains modified code not only for k-firmware but also partly for m-firmware. But I could be wrong about this.

[dazz]

Actually, I have two questions. I also have a few MMBFJ201 and MMBF5457, and they are both detected as BJT's by my T4, while his TC1 does spit out a reading, what's the deal there, please?

Some JFET-MOSFETs are not detected correctly by k-firmware, but are successfully detected by m-firmware.
I have experienced this effect many times. I also assume that Chinese firmware contains modified code not only for k-firmware but also partly for m-firmware. But I could be wrong about this.

Great, I'll try that.. I need to figure out how to flash madire's firmware with the display flipped vertically though.

[madires]

Oh, thanks for the info, that explains a lot. So no firmware upgrades for the TC1 then.
One thing I don't understand is, with a 470K source resistor, wouldn't that set the drain current very close to zero, hence measuring Vgsoff?

No, the TC1 can be updated, but needs a mod for the additional control MCU (either a different firmware or a two-transistor-circuit). And yes, kind of.

Edit: ... as long as it comes with a genuine ATmega.

[dazz]

So this is what I understand the meter should be doing, based on what's in the manual.
It initially measures Vgs an Id with a 680 ohm source resistor like this



These values represent an operating point somewhere in the middle of Vgsoff / Idss, and my guess is that's the info the TC1 is displaying, correct?

Then it adds a 470K source resistor to measure Vgsoff:



Finally removes the source resistor to calculate Idss:



Not even close, probably, just trying to get a better picture of what's going on and what values each meter is displaying

[indman]

No, the TC1 can be updated, but needs a mod for the additional control MCU (either a different firmware or a two-transistor-circuit).

Madires,as you know, now it is impossible to say with 100% certainty that the clones of the LCR-TC series can be upgraded, as there may be "surprises" from Chinese friends inside the package.

[madires]

So this is what I understand the meter should be doing, based on what's in the manual.
It initially measures Vgs an Id with a 680 ohm source resistor like this

All three circuits miss the 470k gate resistor. And in circuit #3 there's also a 680 Ohms source resistor. See CheckPins() in CheckPins.c for the details.

[dazz]

OK, thanks again, guys, really appreciate you help. So the TC1 is showing something "close" to Vgsoff and the small drain-source current the fet is drawing in that condition, but doesn't measure Idss at all. Hope I got it right now.

I'll see if I can upgrade my T4 with madires' firmware and that allows me to measure my fets. Is the procedure the same as with kubi48's firmware? Where is madires repo?