$20 LCR ESR Transistor checker project

[timelessbeing]

Computers have this awesome ability called "search".

[rddube]

Sorry, I don't provide compiled firmware because there are too many different hardware versions. The links for the latest firmware versions:
- k-firmware: https://github.com/svn2github/transistortester/tree/master/Software/trunk
- m-firmware: https://github.com/svn2github/transistortester/tree/master/Software/Markus

Ok, Madires, I understand. Is there a guide somewhere for which version matches which type of screen? My machine is like one of the first ones, sold in kit on BangGood with the 2 line display. Would that be the default version?

Tks again!

[imidis]

Easiest way to identify is look for a similar image to yours then the display listed or look at the driver chip, I think yours is the 1602 LCD which is 2 line 16 character, so I would think 2x16_menu may work.

[kelchm]

Computers have this awesome ability called "search".

Have you ever actually tried searching on this forum? You're better off using Google along with the title of the thread.

[timelessbeing]

@kelchm
The forum search (ie the one in the screenshot i posted) worked just fine for finding the firmware link.

[hussamaldean]

Hi,
I have one of these in the picture and it is T5
but it doesn't work and the screen is blank
any hope to solve it ?

[madires]

Get the schematic, grab a DMM and start checking

[hussamaldean]

Get the schematic, grab a DMM and start checking

let me explain
when I press the button, the screen lit and off
it was working and was so slow and when calibrate it, kaboom everything gone

[madires]

Possibly wrong fuse settings (CKDIV8 set/programmed).

[hussamaldean]

Possibly wrong fuse settings (CKDIV8 set/programmed).

I tried but I can't change the fuse registry either

[madires]

Is the ATmega write protected (lock bits set)?

[hussamaldean]

Is the ATmega write protected (lock bits set)?

LB is 0x3F

[madires]

If there's nothing wrong with your programming it seems to be a bad ATmega.

[Gregi]

I have just finished my tester today and it worked for about 2 seconds. It was powered with 10v supply from my psu and said low batt voltage 6.8X volts and then shuts off. Ofc it wont turn on anymore even on 9V battery. Red LED is not on, display is black. any ideas what to check?

i bought this one
Link to aliexpress

[madires]

That's an AY-AT (schematic in this thread) and typical problems are a reversed SVR05-4 or a bad transistor in the power circuitry.

[Gregi]

Can I use 78L05 instead of HT7550? HT7550 is not available in TO92 package except from china.

[madires]

Yes, but a MCP1702-5002 would be better.

[Gregi]

I have tested the voltages in the circuit and i had 0.2 volts on the out pin of ht7550 so i removed it and tried with 78L05 (thats what i had in my workshop) and it works. So 7550 worked for 2 seconds and died

[GBowes]

Glad you got it working.
Pinout is very different between HT7550 and 78L05. Could you have put the 7550 in wrong? I have done it more than once with these newer regulators.

As Markus mentioned, MCP1702-5002 would be much better (results more accurate). BTW, it has the same pinout as the HT7550

Graham

I have tested the voltages in the circuit and i had 0.2 volts on the out pin of ht7550 so i removed it and tried with 78L05 (thats what i had in my workshop) and it works. So 7550 worked for 2 seconds and died

[dave356]

Hi Guy's

I just purchased 2 of the AY-AT testers (1 kit, 1 assembled) and am going to install some better components.

  680ohm  0.1%
470kohm  0.1%
LM4040 2.5v ref
MCP1702 5v reg

I have also ordered 4 extra ATMEGA328 chips so I can try different FW versions
without overwriting original. (And to have spares)

Can I also install a 16mhz crystal with stock firmware or will I have to reflash.
Will stock firmware work with a 16mhz crystal???

Anything else to replace to improve accuracy?


Thanks

[perieanuo]

Hi Guy's

I just purchased 2 of the AY-AT testers (1 kit, 1 assembled) and am going to install some better components.

  680ohm  0.1%
470kohm  0.1%
LM4040 2.5v ref
MCP1702 5v reg

I have also ordered 4 extra ATMEGA328 chips so I can try different FW versions
without overwriting original. (And to have spares)

Can I also install a 16mhz crystal with stock firmware or will I have to reflash.
Will stock firmware work with a 16mhz crystal???

Anything else to replace to improve accuracy?


Thanks

1.yes, have to reflash.
2.yes,it will work, but incorrectly

Envoyé de mon HUAWEI NXT-L29 en utilisant Tapatalk

[madires]

Can I also install a 16mhz crystal with stock firmware or will I have to reflash.
Will stock firmware work with a 16mhz crystal???

You need to change the MCU clock in the source code to 16MHz (Makefile) and compile a new firmware.

[pappkopp]

Is pd6 supposed to have power the whole time? My wont stay on unless i hold the button down..

[kelchm]

Code: [Select]

AVR Memory Usage
----------------
Device: atmega328

Program:   36136 bytes (110.3% Full)
(.text + .data + .bootloader)

Data:        257 bytes (12.5% Full)
(.data + .bss + .noinit)

EEPROM:      882 bytes (86.1% Full)
(.eeprom)
Using 1.31m and the IR options sure do eat up a lot of space on the lowly ATMega328p... I'd really love to build one of the ATMega1284 variants, but I really don't want to spend close to $100 getting the boards made. Has anyone set up a group buy for these in the past?

[madires]

Is pd6 supposed to have power the whole time? My wont stay on unless i hold the button down..

Using the 328 standard pin assignment PD6 switches the power, i.e. the pin is set high by the MCU at start-up.