$20 LCR ESR Transistor checker project

[hapless]

I didn't know about that, thanks. Undocumented feature? Doesn't seem to make a difference in my case though. Hard to do, too, because if I hold it a fraction of a second too long it just goes into the menu. Using 1.11k r355 by the way.

[madires]

I didn't know about that, thanks. Undocumented feature? Doesn't seem to make a difference in my case though. Hard to do, too, because if I hold it a fraction of a second too long it just goes into the menu. Using 1.11k r355 by the way.

IIRC it's 300ms for the extended display period and 600ms for the menu.

[hapless]

Thank you, that really helps. I finally managed to get the timing right. Looks like half the time I tend to press the button longer when I exit the menu than I do when turning on the device. It sure feels like a bug though if you don't know that it's a feature.

Oh, and there's really no need to "QFT" each of my posts. I rarely make such significant changes to them that would warrant it.

[icpart]

As per Chinese ESR meter I'd like to buy a model that could be upgraded with project improvements. No external power, accuracy and shortcuts would be no problem as I could fix them by myself. But crystal and programming header would be nice (or at least a socket 328)...

This one look nice (crystal, socket, large display, upgradable?) :
http://www.aliexpress.com/item/12864-LCD-GM328-transistor-tester-ESR-meter-Cymometer-square-wave-generator-Free-shipping/2052241237.html

I bought this tester and when it arrives I can do  short review here in the forum. Also I want to make some test with it for software upgrade and 16x2 LCD Panel.

[janengelbrecht]

I Have this one http://www.aliexpress.com/item/frss-shipping-5pcs-latest-Version-Mega328-Transistor-Tester-Diode-Triode-Capacitance-ESR-Meter/1778135807.html same software execpt for display part. Would appriciate information on how to to upgrade firmware I Have the old software for a 2 line alphanumeric display. But my hardware is with a graphical LCD display (newer version!): here it is - feel free to collect it : https://app.box.com/s/rj03grtur3xonxi7mzud

[madires]

I Have this one http://www.aliexpress.com/item/frss-shipping-5pcs-latest-Version-Mega328-Transistor-Tester-Diode-Triode-Capacitance-ESR-Meter/1778135807.html same software execpt for display part. Would appriciate information on how to to upgrade firmware I Have the old software for a 2 line alphanumeric display. But my hardware is with a graphical LCD display (newer version!): here it is - feel free to collect it : https://app.box.com/s/rj03grtur3xonxi7mzud

If the display is ST7565 compatible you can use the k-firmware. Otherwise you got bad luck and have to stick with the cloner's firmware.

[briselec]

nothing obvious at mikrocontroller.net site. i dont speak german and like many diy hobbyists not good with code suppositories. 

I want to know where I can get code suppositories.
That would make me a genuine smart arse   

[con-f-use]

Grave diggin' are we? April 1st.

[magnetus]

can anyone help me please?

i got a Chinese transistor tester and tried to update it using the k-firmware now no screen wont display anything. i got the transistor tester 2014-07 by fish8840

thanks

[andrija]

can anyone help me please?

i got a Chinese transistor tester and tried to update it using the k-firmware now no screen wont display anything. i got the transistor tester 2014-07 by fish8840

thanks

As explained earlier in the thread, many Chinese testers - and the one you mentioned in particular, which I also have myself - use different hardware with which they supply their own, customer, modified firmware. You CAN'T use the vanilla "official" firmware with that.

[magnetus]

[/quote]

As explained earlier in the thread, many Chinese testers - and the one you mentioned in particular, which I also have myself - use different hardware with which they supply their own, customer, modified firmware. You CAN'T use the vanilla "official" firmware with that.
[/quote]

thanks for the input. I installed a HD4480 LCD and it works ok now.
now this display is 16x2
can i use a 20x4?

[madires]

thanks for the input. I installed a HD4480 LCD and it works ok now.
now this display is 16x2
can i use a 20x4?

Yes, but the extra screen estate is used for displaying debugging information mostly (if enabled). AFAIR, supporting 20x4 text displays for the UI is on the to-do list. If you like to have a graphical display, get a ST7565 compatible one.

[mojoe]

Sorry to be asking about a rather old posting in this lengthy thread. I have a board that is almost identical to the one shown in the picture from the posting below. The only difference I can see is the binding posts that mine doesn't have.

I replaced the zener with the 2.5V reference and everything works OK. When I replaced the 78L05 with the recommended LDO regulator, the board still works, but now reports that the 9V battery is low, at 7V. Yes, I did take into account the different pinout between parts.

Other than the added bypass caps, I don't see from the picture that any other part changes were made. Can anyone tell me why the LDO isn't working like it should? For now, I have put the 78L05 back.

Here is my early version of the new Tester with some modifications.
The 10-pin ISP header is soldered, but one side of the frame must be cut out
to match the room left for the header.
The original potentiometer has been replaced to a exemplar with higher resistance
(10k) to save power.
Two blocking capacitors of 100nF each are additionally mounted near the ATmega.
The D1 zener diode is replaced by a precision voltage reference like LM4040AIZ2.5 .
If you don't have a precision voltage reference, you should remove the zener diode at least.
I had also replaced the original 78L05 regulator by my preferred MCP1702-5002 regulator,
because this regulator can also save quiescent current.
Regards, Karl-Heinz

[hapless]

Is it also getting warm? Whenever a regulator does this to me, it's usually because it doesn't like the capacitors on its input or output. The great thing about 78L05 is that it's stable under the same conditions that would make other ones oscillate like crazy. HTH

[mojoe]

I bought the graphical LCD version from EBay (fish...)

I think I bought the same thing. This is what I ordered: http://www.ebay.com/itm/111329306664. What I received has the same circuit board, but the LCD is mounted a bit differently. I'm pretty sure that it is an ST7565, as the backside of the display board is marked with SPI signal names.

I already have one of the 16x2 LCD testers that I bought some time ago. Although listed as having an ATmega328P, it actually has an ATmega168 (SMD). The part number was sanded off and the lock bits were set (jerks). After soldering on an ICSP header, I manged to erase the chip and update it to 1.11k.

So, I decided to go for broke and see about updating the graphic version that I just got. It also needed a header (out the back of the board for the correct pinout), but this one did not appear to be locked. I made a backup of the firmware, then flashed the ST7565 1.11K firmware.

Things didn't go so well this time. I do get text on the screen, but it looks mirrored and upside down. It also looks too large and ghosted. Obviously, there are some differences between the standard firmware and/or hardware and what this Chinese guy made. I can't go back to the original firmware, because AVRDUDE says the file is corrupt.

If anyone figures out how to update this board, please let me know.

[johnh]

This listing (111329306664.) has been removed, or this item is not available.

        Please check that you've entered the correct item number
        Listings that have ended 90 or more days ago will not be available for viewing.



Do have a image of the item you bought

[hapless]

The period shouldn't be part of the link:

111329306664

[mojoe]

I probably mis-copied the item number. I attached a picture. It doesn't show in the Preview. Hopefully you can view it.

[mojoe]

The period shouldn't be part of the link:

111329306664

Thank you. My mistake. The listing of the one with the blue circuit boards is where I ordered from. What I received has red boards, as the picture I just posted. What I have has the blue backlight and white characters. From what I read here, that is supposed to be newer than the one with the green LCD.

[mojoe]

Is it also getting warm? Whenever a regulator does this to me, it's usually because it doesn't like the capacitors on its input or output. The great thing about 78L05 is that it's stable under the same conditions that would make other ones oscillate like crazy. HTH

I didn't think about checking the temperature when I had the LDO installed. I have since put a 78L05 back. I may leave it this way for a while. I have other projects that need attention. I did replace the voltage reference, so that should be an improvement.

[madires]

I replaced the zener with the 2.5V reference and everything works OK. When I replaced the 78L05 with the recommended LDO regulator, the board still works, but now reports that the 9V battery is low, at 7V. Yes, I did take into account the different pinout between parts.

Have you checked the battery voltage and Vcc (+5V) with a DMM?

[madires]

Things didn't go so well this time. I do get text on the screen, but it looks mirrored and upside down. It also looks too large and ghosted. Obviously, there are some differences between the standard firmware and/or hardware and what this Chinese guy made. I can't go back to the original firmware, because AVRDUDE says the file is corrupt.

If the display got any ID you could try to get the datasheet and check if the display needs some additional or special setup. The problem with the modified clones is that the firmware isn't published. Therefore I recommend to stay away from clones with graphic displays unless they are fully ST7565 compatible.

[JoeO]

The period shouldn't be part of the link:

111329306664

The first picture shows that this tester does not give the user a correct representation of the transistor under test.
It shows a BJT transistor but the Vf is 1.27 volts.  This indicates a darlington transistor.

[mojoe]

I replaced the zener with the 2.5V reference and everything works OK. When I replaced the 78L05 with the recommended LDO regulator, the board still works, but now reports that the 9V battery is low, at 7V. Yes, I did take into account the different pinout between parts.

Have you checked the battery voltage and Vcc (+5V) with a DMM?

No, I didn't think of that when I had the LDO installed. I'll check the voltage when I put an LDO back in, later.

[JacquesBBB]

So, I decided to go for broke and see about updating the graphic version that I just got. It also needed a header (out the back of the board for the correct pinout), but this one did not appear to be locked. I made a backup of the firmware, then flashed the ST7565 1.11K firmware.

Things didn't go so well this time. I do get text on the screen, but it looks mirrored and upside down. It also looks too large and ghosted. Obviously, there are some differences between the standard firmware and/or hardware and what this Chinese guy made. I can't go back to the original firmware, because AVRDUDE says the file is corrupt.

I have bought a slightly different one, that has the advantage of having a atmega328p on a socket
http://www.ebay.fr/itm/181534623115?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
I even put a zif support so I can change the processor  easily. I have thus saved the original 328p and
I am playing with a new one and my programmer. 

I have  dowloaded the software from
http://www.mikrocontroller.net/svnbrowser/transistortester/

and I am trying to configure the Makefile for my board, but with moderate success up to now.
I have been using  several options, but the one that  seems to work is mega328_st7565
although I have   the same problem of display :  reverse screen, with large and faded fonts.

The screen is marked 12864-1602_V1.1 (2014.08.01)  from EZM Electronics Studio

Can anybody help ?