$20 LCR ESR Transistor checker project

[Gandalf_Sr]

OK, big thanks to all here, I got my GM328R running on a 16 MHz crystal today. 

I used a TL866A programmer and that gave me issues because I have a Windows 10 PC that has USB 3.0 on the main board plus I have a USB 3.0 powered hub that is fussy about what it works with.  Anyway the TL866A didn't like being connected via the hub and gave me all sorts of weird error messages until I noticed that the TL866A App had a 'Hardware Error' message at the bottom; switching to a port connected directly to my PC's motherboard solved the TL866A issue and then I just erased the AVR and copied the files, .hex to code and .eep to data plus the fuse settings that vinceroger recommended and it worked just fine.

The Atmel datasheet says that CKSEL[3:1] should be 111 for 8-16 MHz but it didn't run when I set them to that so I stuck with 100, any ideas why that's the case?

Also the new calibration routine caught me out as it wanted a second capacitor (12-30 nF) after the >100 nF one.

I attached a picture to show my unit.

[stj]

now test the new function by putting your old crystal into the test socket. 

[GBowes]

The Atmel datasheet says that CKSEL[3:1] should be 111 for 8-16 MHz but it didn't run when I set them to that so I stuck with 100, any ideas why that's the case?

Glad to see you gt it running OK. I was going to suggest that there should have been no error on the TL866 even with a locked chip.

That reference in the datasheet is for using a low power crystal oscillator. The CKSEL for the Full Swing crystals that we use are in the following section.
I am also impressed that you looked at the datasheet. I find that most problems people encounter with microprocessors could have been avoided if the datasheet had been consulted.

Graham

[Gandalf_Sr]

Stj, I put a 4 MHz Xtal into the socket and it detected it correctly   I also saw 'STJ' at the end of the Vn credits

Graham, I'm an embedded design engineer and I read datasheets all the time but I obviously didn't read the ATMega328P one properly or I would have seen that there was a non-low-power oscillator section.

Ted

[pickit2]

hi I got a kit but the FTF is not working it was damaged in the post.
While I am waiting for a replacement, I noticed it is not the same pinout, as most small displays on the market.
This is how the pins on the display connect to the tester, the display has no marking as to pin functions.

[madires]

Maybe a ST7735 based display. I've seen them with different pin headers (8 and 9 pins) and various pinouts.

[vinceroger]

hi I got a kit but the FTF is not working it was damaged in the post.
While I am waiting for a replacement, I noticed it is not the same pinout, as most small displays on the market.
This is how the pins on the display connect to the tester, the display has no marking as to pin functions.

Hi have you got a link too the kit you purchased thanks

[pickit2]

http://www.ebay.co.uk/itm/2016-GM328-Transistor-Tester-Diode-ESR-Meter-PWM-Square-Wave-Generator-J4L5-/371667707701?var=&hash=item56891f2735:m:mRtFR9MCmBteJw-J27eXjGA

I got the kit version on this. but from another seller, details are at workshop, This is the circuit sent by the seller.

[nour]

Hi,
I am very impressed by the amount of pages this thread have , but I am really very confused when it comes to find the thing that I am searching for.

I am looking for the schematic, eagle files, circuit diagram anything
Can any one help and post those stuff on the the very first page or here after my reply(if there is any at all in this thread!!) of course I am talking about LC meter thing

[vinceroger]

Hi,
I am very impressed by the amount of pages this thread have , but I am really very confused when it comes to find the thing that I am searching for.

I am looking for the schismatic, eagle files, circuit diagram anything
Can any one help and post those stuff on the the very first page or here after my reply(if there is any at all in this thread!!) of course I am talking about LC meter thing

what meter do you have?

[nour]

Hi,
I am very impressed by the amount of pages this thread have , but I am really very confused when it comes to find the thing that I am searching for.

I am looking for the schismatic, eagle files, circuit diagram anything
Can any one help and post those stuff on the the very first page or here after my reply(if there is any at all in this thread!!) of course I am talking about LC meter thing

what meter do you have?

I am sorry, what are you talking about?

I am asking about schematics for LC meter design,
Is there any thing like that in this thread?

[vinceroger]

Hi,
I am very impressed by the amount of pages this thread have , but I am really very confused when it comes to find the thing that I am searching for.

I am looking for the schismatic, eagle files, circuit diagram anything
Can any one help and post those stuff on the the very first page or here after my reply(if there is any at all in this thread!!) of course I am talking about LC meter thing

what meter do you have?

I am sorry, what are you talking about?

I am asking about schematics for LC meter design,
Is there any thing like that in this thread?

manual pdf link im sure this has a schematic in it
https://github.com/svn2github/transistortester/blob/master/Doku/trunk/pdftex/english/ttester.pdf

[madires]

I am asking about schematics for LC meter design,
Is there any thing like that in this thread?

https://github.com/svn2github/transistortester/tree/master/Hardware

[Mek]

Hi, all,
I just registered to ask about my problem with a Chinese clone of this meter. I bought this one from ebay recently. I wanted to measure ESR of a cap and forgot it was still charged (25V) which ruined the meter, it would not even turn on. I replaced the 7805 and now the meter turns on but displays bogus data - with no component to test inserted, it shows "Testing..." and after a longer while it shows it detected "BJT-NPN" with beta 1.5M or so, which is like and it is the same even if shorting pins 1-2-3.
I would like to fix the meter if possible. Does this look like the AVR is fried? I cannot replace it, it has 32 pins and is without a socket and in the smallest possible SMD package of course
I also knew that someday this happens that I forget to discharge capacitor before testing, but not that it will be anytime soon Ok, so I thought, is there no possible protection from such mistake? If it is, why is it not part of the original circuit? Or is it optional and the Chinese do not include it to cut cost and increase sales? Well, they were successful because I liked the meter and still need an LCR-ESR meter so I ordered another one (thank god they are so cheap).
What are my options in fixing this meter, can anyone suggest, please?

[Gandalf_Sr]

What are my options in fixing this meter, can anyone suggest, please?

Wait for someone else to reply but couldn't you just buy a new ATMega328P chip and reprogram it, what else could be wrong?

[stj]

post internal foto's

you need to replace the atmel with hot air and obviously program the replacement.

[bitseeker]

I would like to fix the meter if possible. Does this look like the AVR is fried? I cannot replace it, it has 32 pins and is without a socket and in the smallest possible SMD package of course

It does sound like the ATmega is fried and is the most common thing to go when connecting a charged capacitor. As stj said, you'll need a hot air station to replace the chip.

Ok, so I thought, is there no possible protection from such mistake? If it is, why is it not part of the original circuit? Or is it optional and the Chinese do not include it to cut cost and increase sales?

There is a way to protect the chip from such a mistake and, yes, it's an optional feature of the original design (and described in the documentation). Of course, it costs less not to include optional parts. However, just this year someone in China made a version that incorporates optional features including input protection.

Here's an example of one: http://www.ebay.com/itm/371667156523

[indman]

Hi, madires! Checked operation of a tester of AY-AT ST7735 at a frequency of 20 MHz. All functions work much quicker, than with quartz 8 MHz. The generator is capable to give a signal with a frequency of 5 MHz, and the frequency counter can measure signal frequency to 10 MHz!  An example on photos which I apply.
There are problems in case of measurement of the low-impedance resistors and inductance. I will try to show them in the following post.

[indman]

There are problems in case of measurement of the low-impedance resistors and inductance. I will try to show them in the following post.

Unusual result of measurement of inductivity 240 µH at a frequency of quartz of 20 MHz. Also uncertainly the low-impedance resistors are defined. An example on a photo.

[madires]

Thanks for the report! I'll check if I'm able to reproduce the issues.

[jm_araujo]

Hi, friends! For a tester of DIY Kit "AY-AT" it is necessary to change in config_328.h  line
#define LCD_RES PD4 on
#define LCD_RES PD0 
  According to the diagram of a tester the output 2 processors is connected to contact of RESET of the display.

I have a AY-AT kit and being a bit lazy installed this version: https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg1016572/#msg1016572 and didn't work, only got a white screen.

After seeing your message I decided to compile my own with the suggested change and it now works fine! My display must be the same as your friend's!

[bitseeker]

Checked operation of a tester of AY-AT ST7735 at a frequency of 20 MHz. All functions work much quicker, than with quartz 8 MHz. The generator is capable to give a signal with a frequency of 5 MHz, and the frequency counter can measure signal frequency to 10 MHz!

Excellent. I guess I'll have to upgrade mine at some point.

[indman]

Hi, friends! If it is interesting to you, then I on pages of the topic made comparing of the software from Karl-Heinz Kübbeler and
Markus Reschke. The forum is Russian-speaking, but I think that according to photos it will be clear without the translation. I hope that this information will help two dear authors of this project to improve operation of a tester. Once again big gratitude for huge work!
The topic contains only 3 pages, comparing of firmwares begins with the 2nd page (a post #703275). Link to the topic http://vrtp.ru/index.php?showtopic=26994&st=0

[madires]

Nice side-by-side comparison! Thanks indman!

[TheBay]

Just compiled and flashed Trendy 1.25m for my MK-328 and fitted a 16Mhz Crystal.
Removed options for "Rotary Encoder"

Just a quick question, is it correct that it cycles through the tests rather than display it on the screen and then switch off, also I have to double press the Test button to enter the menu is this right?

Video attached.

If anyone wants this compiled for the MK-328 please let me know and I'll attach it.