$20 LCR ESR Transistor checker project

[mauroh]

You might ask Kubi in the German forum to include your fimware mod in the k firmware.
I would then adapt my progs accordingly.

That will be great!!
Since I think others around the world have implemented something that use the actual serial output, my idea was to have an option on the makefile to select the different serial format standard/mauro/...

Is too diffucult or impossible when simply relying on what the Transistor Tester
currently spits out. Hence my request for duplex serial communication for the larger ATMEGAs.

Therefore wrote separate progs for each component. Currently these progs are
BJT, JFET, MOSFET, OPTO and RES. The prog CAP for capacitors being the last on my list
will be available soon. Still needs to simmer a bit.

We basically followed the same path arriving to different conclusions
My actual program visualize on a PC screen the same output of the TT but to perform evaluations on the measures a lot of parsing is needed and slowed me a bit

Well done 
Mauro

[madires]

I kept all the optocouplers used for the previous CTR manual measurement in the same order and this is the results with the 1.22m firmware.

Thanks for the measurements! I think I should add the output of I_f for a better understanding of the CTR value. Since the LED's cathode and the BJT's emitter are connected to one probe they share the voltage drop across the current shunt. If I_e increases the voltage drop increases too, and therefore I_f will decrease. Unfortunately the CTR is non-linear.

1)
For the ESR measurement you selected the test poits 1 and 2 while on the k firmware are 1 and 3
My issue is that on the M12864 I can't use the banana plugs anymore to perform the measures, because this are connected to TP1 and TP3
My main use of the banana plugs are with the tweezers that are really useful

That's an easy fix I'll change it to 1-3 to be compatible with the k-firmware.

2)
I keep the TT inside my bag and I find it always on.
On the display I found "done!" or "No component found!" and it stay there forever.
Also turning the encoder to enter the menu, after I select Exit it appear "done!" but it stay there forever.

Is there a blinking cursor at the bottom right of the display? To switch off the tester please press the button for 0.3s at least. It will show a "bye" and power off.

[mauroh]

Thanks for the measurements! I think I should add the output of I_f for a better understanding of the CTR value. Since the LED's cathode and the BJT's emitter are connected to one probe they share the voltage drop across the current shunt. If I_e increases the voltage drop increases too, and therefore I_f will decrease. Unfortunately the CTR is non-linear.

You are welcome, and thank you for the implementation of this function.
Can't wait to see a Chinese clone with the 644 for 17$ where we can have all the options enabled by default without any flash/processor limit 

Is there a blinking cursor at the bottom right of the display? To switch off the tester please press the button for 0.3s at least. It will show a "bye" and power off.

Yes, forgot to mention the ">" cursor on the right-low corner.
If it goes in this state it will never self power off.
The problem is that if it goes in this state in the bag it will drain the battery.
Is it possible to have an optional self power off after x minutes of inactivity?

I think I will just add a switch on the battery.

Mauro

[kenabi]

so i snagged one of the black case fish8840 models ( http://www.ebay.com/itm/131539364479 ) and it j ust gives me the blank screen of doom. tossed a resistor in there, still blank screen. anyone have a way to fix this? not seeing much in the thread about this model.

[madires]

If it's dead on arrival ask the seller for a refund. If the LED is lit after powering on it might be the display.

[kenabi]

lcd lights up, it just doesn't show any text. powers off after x seconds. any way to test?

[madires]

Bad contrast setting? You could check it with a compatible display, a DSO or Logic Analyzer.

[kenabi]

don't have a display, only got one of those cheap diy dso kits, and no LA.

[stryker]

Thanks for this great project! Im looking for this SMD breakout - or maybe source files for it?

Actually I'd go for one of those too - and put mine in an enclosure.  Can anyone recommend a SMT breakout other than this if they're using one, and where did you find it? 

Thanks

[timb]

Hey guys, just grabbed one of these MK-328 units on eBay to replace my trusty MK-128 (which has worked flawlessly for over a year now, but I really wanted a graphic LCD). Does anyone know what branch/compile options I should use for this unit? (I'm wondering about its particular display, etc.)

I haven't been following development, so I'm not sure what's changed. I'm trying to read back through the thread but it's a lot of pages.

http://www.ebay.com/itm/321936118996

[bitseeker]

With so many variations, it may be prudent to check inside and verify the display controller that's in your particular embodiment.

[kenabi]

uses a Lx-12864TS spi lcd module, no visible chips on it, 12 contact flex cable, can't even find who makes it. from left (when staring at side of board the avr is soldered to) contact 1 and 6 are ground, contact 2 is +5v when tester is 'on', board trace is marked 3v3. riiight.

[micro88]

@timb

I think you can use the Makefile given at https://yadi.sk/d/yW8xa5NJgUo5z/Mk-328/Firmware  to get yourself started.

Best regards.

[Melkocha]

Hi folks!
I have built a model T4 and it is costing me too much to make it work.
The problem is the following:
I turn it on and, after of first screen -without connecting anything- and after 18 seconds appears on display:
"Cell!" and, below: 1. 08V   0mV  1. 43V,  then began the routine of testing T1, T2, etc.
It the same if I connect any component to any TP.
If I put a LED does not see it is flashing and does so only when the message "short Probes!" appear.
I tried several firmwares, particularly from mid last year.
I have checked the circuit and it seems to be correct.
Can be the value of CAP EMPTY LEVEL?
Anyone have any suggestions?
Thanks in advance!

[tom666]

Probably damaged input ports of the MCU (result of measurement the charged capacitor).

[Melkocha]

Probably damaged input ports of the MCU (result of measurement the charged capacitor).

Thanks Tom, but I made sure not generate this problem and, however, I changed the chip: The result was exactly the same.
In these tests, very sporadically, the tester seems to work and appears the legend of "no component...", and in others, the values of the second line change: 0 mV appears in third place, etc.

1) Any other suggestions?
2) What mean 3 values ??in the second line below "Cell!"?
Thank you again.

[mauroh]

Do you mind to post some picture of your assembled tester?
In case someone can spot something wrong
Mauro

[bingo600]

I just got this one
http://www.ebay.de/itm/152011732946

Does anyone have a pointer to the firmware that fits this one (source + makefile)

TIA

/Bingo

[mrjoda]

i bought T4, it works somehow, so... i made bad decision(after hour) i flash it with new firmware and... suprise ! it does not work again !  of course, it works but it measure totaly bullshits, i try all released versions of FW, fuse as recommended (f7,d9,fc (04 gives me verification error)). Calibration shows some number, it pass when ask me to connect cap i connect it, measure exact value and after that, when calibration is complete, measurement wont work, it missdetect almost everythink as capacitor, at random pins with thousands of uF and F... For example, when i connect 100nF cap between 1 and 2, its shows capacitor between 3 a and 2 and capacity 3654uF BUT if i reconnect cap when this shit is turn on to 3 and 2, it measure correct value. When i press buton, again missdetect.

 With original firmware was values pretty close to reality


any suggestion ?

thanks

[madires]

Have you also updated the EEPROM?

[mrjoda]

yes, HEX + EEPROM + fuses,
classic tools USBASP + AVR Extreme Burner

[Melkocha]

Hi folks!
I have built a model T4 and it is costing me too much to make it work.
The problem is the following:
I turn it on and, after of first screen -without connecting anything- and after 18 seconds appears on display:
"Cell!" and, below: 1. 08V   0mV  1. 43V,  then began the routine of testing T1, T2, etc.
It the same if I connect any component to any TP.
If I put a LED does not see it is flashing and does so only when the message "short Probes!" appear.
I tried several firmwares, particularly from mid last year.
I have checked the circuit and it seems to be correct.
Can be the value of CAP EMPTY LEVEL?
Anyone have any suggestions?
"Probably damaged input ports of the MCU (result of measurement the charged capacitor)."
Thanks Tom, but I made sure not generate this problem and, however, I changed the chip: The result was exactly the same.
In these tests, very sporadically, the tester seems to work and appears the legend of "no component...", and in others, the values of the second line change: 0 mV appears in third place, etc.

1) Any other suggestions?
2) What mean 3 values in the second line below "Cell!"?

Another clue:
The values of Ri_Lo = Ri_Hi = .0 Ohms

What do you think?

[madires]

yes, HEX + EEPROM + fuses,
classic tools USBASP + AVR Extreme Burner

Do you power your tester with a battery or a PSU (linear or switching mode)?

[mrjoda]

i tried both, 9V battery with 8,5V and linear PSU set to 9,5V. Nothing change. When i get my camera back i will shoot a video. I will capture process of calibration and i try measure something. I checked all resistors and values are correct (measured with fluke 187). Reference is 2,4953V stable,  supply 4,9863V stable.

I will put here a calibration numbers later.



is there any repository with original software from china ? i rushed and i did not read values before replacing firmware 

[TJM]

A month ago I bought MK-328 from ebay, since then I used it a lot to test hundreds of new "old stock" transistors. One day the battery died, it was already late and I did not have replacement, so I used an old 9V NiMH rechargeable battery, which worked fine for a while, then suddenly the display faded and the tester switched off. The next day I put in a fresh 9V battery and noticed two things: the unit lost  its calibration - but I did it following the on screen procedures and everything went back to normal except a second thing - i think it had LCD contrast settings stored somewhere in memory, at the moment I have to look at it with an angle because the screen is dark.
Does anyone know how to fix it ?