$20 LCR ESR Transistor checker project

[Calambres]

Then which is the best option today? 

M328Kit+TFT RGB(GM328A) ATMega328 Dip form factor. It is easy to make an adapter for this clone for ATMega644.
This is the best option for today, so as not to get a fake and wasted money, nerves and time!

Well, that's the one I have (the T7-H was purchased for a friend).

Mine is the M328Kit+TFT(AY-AT) but has a buggy SW that prints trash instead of some symbols. Don't really know how to update the SW. I must find a "guide for dummies" somewhere 

[Obelix2007]

Bohu has updated the Czech, German and English PDF documentation for 1.49m: https://github.com/madires/Transistortester-Warehouse/tree/master/Documentation

... Look to the Documentation of madires.

Regards Horst

[morgan_flint]

Then which is the best option today? 

M328Kit+TFT RGB(GM328A) ATMega328 Dip form factor. It is easy to make an adapter for this clone for ATMega644.
This is the best option for today, so as not to get a fake and wasted money, nerves and time!

Don't you think the Hiland M644 is also a good option?

A bit pricey now (nearly $40 at Banggood when, f I remember well, I got it under $20) but already M644 and complete with prescaler and voltage booster for zener testing. AFAIK, no fake CPUs in this one also.

[indman]

Don't you think the Hiland M644 is also a good option?

Yes, this is also a good option, but now it has almost disappeared from sales and sellers' offers. In addition, it is equipped with a monochrome display, which slightly reduces its merits.

[morgan_flint]

True, it's hard to find now, even Banggood is out of stock now (the ad says "Restocking. Expected to ship before Jun 15").

The only place that seems to have stock is here at taobao, (and very good price, $17 + shipping, I suppose). Unfortunately, I don't know how to buy at Taobao or if they would ship outside China. This seller also has two other versions of the tester, and he seems to be the manufacturer of the kits; maybe he would be interested in making a 644 version with a color screen if somebody tells him 

[snapper]

hi,
i've often bought from taobao, but unfortunately that only works through a so-called sales agent and causes additional costs such as overseas shipping and agent fee. and depending on the country, there may be additional customs duties because bhiner does not collect them immediately, e.g. aliexpress or ebay.
best regards

https://www.bhiner.com/

[elecdonia]

Ah, by the way, anyone knows what is hFEr?

hFEr=REVERSE_HFE
"All transistors have inverse Hfe, since you can always swap the collector and emitter. This is equivalent (but not strictly identical - Hfe is a large signal, BF is a small signal hybrid signal) to the SPICE BR parameter, just as BF is equivalent to Hfe."

Link: https://www.physicsforums.com/threads/what-is-reverse-hfe.305553/

There is a class of small-signal BJT transistors which have “reverse Hfe” of similar magnitude to their forward Hfe. In addition their E-B reverse breakdown voltage is similar to the E-C breakdown voltage, typically ~25V.

These devices are marketed for “audio muting” applications at analog line-level signal levels ( <5V RMS ). The E and C pins are interchangeable. A typical application circuit sends the output from an opamp through a ~1k ohm series resistor followed by the audio muting transistor operating as a controllable shunt to ground. Application of base current to the audio muting transistor provides >80dB of audio muting. The transistor is an open circuit when the base is reverse-biased. The reverse bias voltage is usually >10V. This is large enough to prevent clipping of the audio signal.

[snapper]

True, it's hard to find now

If you add up the sales agent fee, shipping costs and taxes/duties, it's just as expensive as this one and he can deliver immediately

https://www.elecbee.com/en-29467-Original-M644-Transistor-Tester-LCR-Diode-Transistor-Zener-Quartz-Measurement-Frequency-Counter-PWM-Wave-Generator-Online-ESR

Economic Shipping $5.00 About 5-15 Days to EU

[Pukker]

How frustrating can the Chinese be?
Nice project by Markus Frejek, Karl-Heinz Kübbeler and all others,
the Chinese must be thinking "Aha, nice money making project"
They started making and selling useful versions.
Now they are back in their core business, MAKING FAKE. AARCHHHH

[Yuriy_K]

For k-firmware using ILI9341 developed a new font for outputting 8 lines. In the original version, 7 lines were displayed. There are a lot of changes, now I'm checking all the output options on the screen. Who is interested write.

An example of a full font and an example of measurement in the photo...

[elecdonia]

Just adding another data point on the LCR-TC2 to this thread. Old vs new version, both from "Z industry store" on Aliex 18 months apart. New: Custom case based on original generic case, f/w v3.1E, PCB T7-PLUS v2.0, unmarked 32 pin MCU

This MCU is likely to be LGT8F328P.  Other EEVblog posts report successfully replacing LGT8F328P with Atmel ATmega328P. The hardware mod is simple: Only a few pins have different functions. However, existing -K or -M firmware needs modification for mega328P to work with this PC board. When time permits I plan to try this myself.

This week I received 5x LGT8F328P boards which are (somewhat similar) to the popular (Arduino) "pro-mini" board. A "boards" definition package is available for using these LGT8F328P boards with the Arduino IDE. I intend to experiment with Transistor Tester software which has been ported to the LGT8F328P. But first I will get familiar with the LGT8F328P by comparing its performance to Atmega-based Arduino boards (which I've been using for >10 years).

To me the LGT8F328P has an interesting feature set: Its I/O pins have full 5V capability, and a "handful" of them (not all) are rated at 80mA. This may be useful for the Transistor Tester because larger I/O output current corresponds to lower internal resistance/impedance. This might improve accuracy for measurements of small resistance and for capacitor ESR. The LGT8F328P would get even more attention from me if the manufacturer introduced a version with 64k flash.  

[vk3em]

I am thinking about building my own LCR tester based on one of the open hardware designs. I am looking for something M644 based and prefer SMT components rather than through hole.
I will get the PCB made professionally so plated holes and vias is not an issue. I have found the Mega 4GSL but are there others I have missed? Happy to consider all options.

Cheers
Luke

[Yuriy_K]

I show my version of the conversion of Hiland M644 to ILI9341. Changes in the scheme and pictures of modernization and measurements. So far, only what I have debugged.

[Yuriy_K]

Measurement examples did not fit due to limitations.

P.S. Made a new body. Once placed in the housing, it must be recalibrated due to the effect of the dielectric between the three lower redundant inputs.

[snapper]

hi yuriy,
don't understand the green connection and the series resistor for BL certainly ohm and not kohm!?
do you also have the firmware as hex and eep and would you kindly provide them?
I am currently working on an (improved) pcb copy and will take the changes into this immediately.
I also found this booster mod (for the zener test voltage) on github

[Yuriy_K]

don't understand the green connection and the series resistor for BL certainly ohm and not kohm!?

In my board there was 2-3 ohms between AGND and GND - a defect in the board. Eliminated with a short jumper.
New displays require resistors of the indicated kOhm ratings.
I just finished fixing the firmware yesterday, but I haven't fully checked it yet. Here are the fixes for today.

[snapper]

New displays require resistors of the indicated kOhm ratings

yes, the 5x 10k in the data lines are fine, but 68-100k in the line for the backlight?
there won't be much light! 30\$\Omega\$ are right ! display needs 3,2V 60mA for backlight.

[Yuriy_K]

there won't be much light! 68-100\$\Omega\$ are right ! display needs 3,2V 20mA for backlight.

I indicated the real value in my circuit, if you want to burn the display, put whatever you see fit.

[snapper]

hello,
on the board a 1k resistor R6 is already inserted in the base line of the transistor,
according to the data sheet pin LED can be connected directly to 3V3 for maximum backlight,
nothing will burn there! where can you get the information for the 68-100K resistor ?
regards

[indman]

snapper,
There is a factory datasheet for each type of display, which indicates how to connect the power and backlight circuits.
This datasheet and be guided by the connection. This is a childish question for a person who understands electronics.
It's just that displays of the same diagonal exist have slightly different backlight control - in one it is controlled directly through a limiting resistor, in the other by a certain voltage level to the base of the control transistor or PWM.

[snapper]

hey,
this is a project by Boleslaw J. and my idea to develop a circuit board for it.
the project has now been tested and completed and the pcbs are available.
see https://www.mikrocontroller.net/topic/transistortester-avr?page=31#7381379
and ongoing.
if interested on adapter PCB please send me PM

[madires]

The ATmega644 adapter for the AY-AT clone is accompanied by a modified m-firmware with added graphical output of the IR signal in the IR receiver/decoder function. That mod is done by Boleslaw J. (boleslaw_43): https://github.com/madires/Transistortester-Warehouse/tree/master/Firmware/m-firmware

Edit:
And the PCB layout of Boleslaw's ATmega644 adapter for the AY-AT clone (format: Sprint Layout 6): https://github.com/madires/Transistortester-Warehouse/tree/master/Hardware

[.RC.]

Is the 644 Upgrade to the AY/AT board via the daughter board only for the increased memory. I ask as I cannot see where you can easily use the extra pins available on the 644. I know all the pins on the 328 are used, so I thought you were restricted to what you can switch on in the firmware.

[snapper]

The control of the display has been changed to hardware SPI and there is a new generator output GEN (OC1B on pin 13) on the daughter board with a frequency output of 2 MHz.
the rest e.g. modified m-firmware with added graphical output of the IR signal, read in mikrocontroller forum posts
https://www.mikrocontroller.net/topic/transistortester-avr?page=31#7401381
search for the contributions of boleslaw j. (all in english)
the new GEN connection of the adapter can be wired to the terminal block of the old one, as this is no longer required,
the old connection / conductor track must be severed for this purpose!

[Sudya]

Comparison of LCR-TC2 testers and their firmware.
EFUSE 0xF7 (Solution for switching off the tester when measuring capacitors).