$20 LCR ESR Transistor checker project

[GarySlaghammer]

The selftest completes, apart from not recognising a 4-30nF capacitor and reporting 0pF or a fluctuating value until it moves on. However, on completion it successfully tests a capacitor of such value connected between T1 and T3, giving reasonable results.

T1: Ref=1081mV RHf=864
T2: +RL- 12 13 23 -4 -4 -4
T3: +RH- 12 13 23 -2512 -2512 0
T4: -2512 -2512 0
T5: RH- 2317 0 3
T6: RH+ -4502 -6 -6
T7: RH/RL -7 -1 -2

[CaptainBucko]

it seems that all of the TC1, T7, ... you can get nowadays are bad counterfeits without the 328 chip (one listing claimed 328, but I read that those are just re-labeled ones, so even worse).

You can generally replace a Logic Green LGT8F328P with ATmega328 using wiremods and some PCB track cutting and making your own ISP interface. I have successfully done a few of these. The LGT8F328P has 32 pins / 8 pins per side that mostly aligns with the ATmega328. Note that not all TC1,T7, etc use the 32 pin LGT8F328P, and there is no conversion solution for these units.

However, it can be easier to just buy a GM-328 which comes with an ATMega8 in a DIP package, and swap the MCU with a new programmed one running latest firmware, or add your own ISP interface.

[indman]

The selftest completes, apart from not recognising a 4-30nF capacitor and reporting 0pF or a fluctuating value until it moves on. However, on completion it successfully tests

My assumptions were confirmed - the results of the hardware tests clearly show that your tester has BIG problems with the measuring ports of the controller! Your tester will not be able to work correctly, and you will again face the same problems as before.
My advice is to remove the controller from the board, thoroughly flush this place from the flux. If there is a spare controller, it is better to solder it and repeat the hardware tests after programming. I would also recommend checking the serviceability and update soldering of the 6 measuring resistors 680ohm and 470koHm

[GarySlaghammer]

Thank you. I am inexperienced with SMD, so my technique is probably to blame. I used some Chipquik CQ2LF and 95.5Sn/3.5Ag/0.7Cu solder. Usually I use multicore 60/40 for my projects, valve and transistor.

[VIO47]

Hi All, Happy New Year!
I am playing with this tester since few days, for the moment it is on breadboard, I want to see how it works and then will get to PCB design and all others. I have tested with ILI9341 SPI display and it works very well, I am not so concerned about accuracy, not sure how much I can expect and for sure not on a breadboard.
But right now I want to do something else, I want to use another type of display which is not listed, it is an ST7567 I2C display which I have it for long time, only did some tests to see how it works but never used it for something. So, I have created the .c and .h libraries for my display similar with the available libraries, matched all variables, updated config.h,  my code compiles with no errors but still cannot get the display initialized and of course doesn't showing anything. Most probably there is something else I should update but cannot figure it out.
Did anybody attempted to make some changes in the code or can advise what else needs to be updated? I am using an Atmega328P, by the way.

[madires]

Have you also added the new display driver to Makefile (c and h files) and config_<MCU>.h (configuration for driver)? Do you have a DSO or logic analyzer?

[VIO47]

I am working with Atmel Studio so don't think I need to update Makefile manually and config_<MCU>.h is updated. Already checked the SDA and SCL with a DSO and I can see the clock signal and data flowing but it is not what the LCD is expecting to get Thank you, will keep checking.

[Cricri]

I have a LCR-T7 (T1 clone, with 160x128 screen). At some point I also had a LCR-T1 but sold it. I chose to keep the T7 as I prefer the proper button cap over the tactile switch behind the face plate film.
Did anyone notice that the battery depletes when not in use? I'm not an electrical engineer so use my T7 sporadically, and its 300-350mAh stock battery was systematically low whenever I used the unit. So swapped it for a Nokia BL-5J 1430mAh battery (plenty of space in the case), and also added a switch so that I can disconnect the battery when not in use. It turns out that as soon as I switch it on (i.e. "connect" the battery), the tester switches on, so it's actually useful as I can put a component in, flip the switch on, and the test happens.
I would try to update the firmware but don't know how to proceed. Also the stock uc is a surface mounted Atmega 324PA, so I don't imagine it's an easy job.

[madires]

The high quiescent current is a well known issue of the older TC-1/T7 models which use an additional MCU for managing power. For upgrading the firmware to an OSHW one you will have to modify the tester first (explained in the Clones file of the m-firmware). It's either reprogramming the additional MCU or replacing it with a simple two-transistor circuit.

[Feliciano]

... or sometimes some Li-Ion batteries have issues including high self-discharge rate.

[stj]

the problem is the crap STC microcontrollers dont stay in sleep-state even with the new firmware.
replacing them with the 2 transistor mod is the fix.

[Cricri]

the problem is the crap STC microcontrollers dont stay in sleep-state even with the new firmware.
replacing them with the 2 transistor mod is the fix.

My fix works too. A bit brutal and aesthetically odd, but works well! 

[Beau]

Hi

I have killed my Dtu-1701 and I need to flash the Atmegaa328p with the original firmware (tried the BSIDE firmware it works but wont read capacitors) I see you have uploaded the software I need but my programmer uses Hex and Epp file format and not Bin file as in you upload.  I'm new to this programming and was wondering if you have the file format I need?

[madires]

Have you also set the fuse bits of the replacement ATmega328?

[wifikebab]

Hey folks,

Pardon me, but, is there a good place to get a device with genuine parts?  like is the tindie Hiland DIY Multifunction Transistor Tester Kit a good source? There's so many pages of great research here, but I'm not sure what to search for first. Please forgive my ignorance. 

Any assistance you can offer toward making a great little unit or sourcing one would be much appreciated, thank you. 

[madires]

How to spot genuine and fake ATmegas:
- MCU in DIP is usually an genuine ATmega.
- APT32F172K8T6 has different power pins:
  - 32-LQFP/QFN: 18=Vss, 19=Vdd (ATmega328 32-TQFP: 5=Gnd, 4=Vcc)
- APT32F172K8T6 uses SWD port for ISP:
  - 5 pins: Vdd, Vcc, F_SDAT, F_SCLK, F_RST
- Testers with APT32F172K8T6 often lack a quartz crystal.
- LGT8F328 has slightly different pins:
  - QFP32L: 21=PE2/SWD      (ATmega328 32-TQFP: 21=Gnd)
            18=PE0/SWC/APN4 (ATmega328 32-TQFP: 18=AVcc)
- LGT8F328 uses SWD port for ISP:
  - 5 pins: Gnd, Vcc, SWD, SWC, Reset

The easiest way to find a genuine ATmega is to look for the DIP version.

[stj]

Hey folks,

Pardon me, but, is there a good place to get a device with genuine parts?  like is the tindie Hiland DIY Multifunction Transistor Tester Kit a good source? There's so many pages of great research here, but I'm not sure what to search for first. Please forgive my ignorance. 

Any assistance you can offer toward making a great little unit or sourcing one would be much appreciated, thank you. 

i think "Hiland" is a brand exclusive to Banggood

[stj]

whatever you buy/build,
you DONT want it using a 328 chip.
there is no upgrade path.

look for something using a 324 or 644 chip.
then you can upgrade all the way to a 1284 and have 128k of flash instead of being stuck with 32k - which is not enough for all the options.

[hapless]

Ideally, maybe. But in reality, a unit with a genuine DIP 328 is easier to find than anything else in most places, and if you don't care about getting all the options, then that's your best bet unless you build your own. Then, of course, go as wild as your budget allows.

Oh, and hasn't someone created a DIP-to-SMT upgrade board and shared its design in this very thread?

[stj]

a dip adapter could be tricky as most dip-based testers have the mcu under the display creating clearance problems.

[indman]

https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg5340554/#msg5340554
stj I don't see anything particularly complicated, the height of the adapter will be commensurate with the height of the DIP chip.

[all_repair]

I was expecting someone to include the transistor tester into their digital multimeter.  Did suggest to Dave before.

[indman]

I was expecting someone to include the transistor tester into their digital multimeter.

There were already options when Chinese friends built a transistor tester into an oscilloscope.
No properly (without gross errors) working tester has yet been found.I think the same fate awaits this combination device.

[yang]

Could you please tell me the accuracy of this tester when measuring resistance, capacitance and inductance?Is there a precision value?

[indman]

Could you please tell me the accuracy of this tester when measuring resistance, capacitance and inductance?Is there a precision value?

It's just a TESTER and not a professional industrial device, so it would be foolish to require it to have any rigidly fixed accuracy values.
But if you use HIGH-QUALITY components in this project, as well as AUTORS FIRMWARE, then it is quite possible to get readings within 1-2% error.