Need help flashing $20 China component tester - Page 1
Forum section: electronics / repair

author: poot36
author_rank: Frequent Contributor
timestamp: July 01, 2021, 11:57:48 pm
content: I have what I think is a LCD-T4 component tester that I managed to damage the inputs to the micro on with a charged capacitor. I have a replacement Atmega 328p chip but have been unable to get the unit to display anything besides a blank or screen with a constant shade of grey. I am using the code from here:https://github.com/Mikrocontroller-net/transistortester/tree/master/Software/trunk/mega328_T3_T4_st7565I have also tried this code as well:https://github.com/Mikrocontroller-net/transistortester/tree/master/Software/trunk/mega328_T4_v2_st7565. Not really sure that I am flashing it correctly, as all I have for a programmer is a Arduino UNO set up as a ISP programmer and have tried flashing just the hex file and the the hex file + the epp file and no change. Not sure if I need to set the fuse bits or not. I am currently testing this on the partially broken micro that came with the tester just to see if I can get it working before swapping the good chip onto the board. I have also tried setting the fuse bits to this: lfuse:w:0xff:m -U hfuse:w:0xdb:m -U efuse:w:0xfd:m from this project:https://github.com/wagiminator/ATmega-Transistor-Testerand no change to the operation. It did give me an error about the efuse bit though: avrdude.exe: WARNING: invalid value for unused bits in fuse "efuse", should be set to 1 according to datasheetThis behaviour is deprecated and will result in an error in future versionYou probably want to use 0x05 instead of 0xfd (double check with your datasheet first).avrdude.exe: 1 bytes of efuse verifiedThe original fuse bits were: (E:01, H:D7, L:FF) and after changing them they are this: (E:FD, H:DB, L:FF). It does mention that these are safemode fuses so they may not be the correct fuse's that I am needing to change.Not really sure what I am doing wrong here as I am a hardware person not a software person.

author: poot36
author_rank: Frequent Contributor
timestamp: July 03, 2021, 02:18:29 am
content: Did some more searching and found this persons post:http://boffin.nl/wp/transistor-tester-mtester/and by the look of the pictures the unit appeared similar to mine. But when I tried the firmware listed, it made things worse! I now have no backlight and even after trying to flash the other versions on the GitHub I was unable to get the backlight to turn back on. Have I somehow totally killed it now?

author: Diyaudio_enthusiast
author_rank: Contributor
timestamp: July 03, 2021, 08:00:29 pm
content: I'm no expert.how about uploading the hex file of blink sketchIf that works, you can proceed to next step.

author: poot36
author_rank: Frequent Contributor
timestamp: July 06, 2021, 02:37:39 am
content: I just realized that even if I were able to flash replacement firmware to the chip it would not be calibrated and I have now way of calibrating it so it would not be very useful anyways. I have decided to buy the next model up from the one that I currently have that has a color screen and a removable ATmega 328p chip so that if I managed to blow it up again I should have an easier time to fix it as I can dump the chip before I wind up damaging it. Also this one has a model number associated with it so that is good as well.

author: tunk
author_rank: Super Contributor
timestamp: July 06, 2021, 09:17:21 am
content: I think you can calibrate it this way:https://www.elektroda.com/rtvforum/topic3354445.htmlOr mayby not:https://www.eevblog.com/forum/testgear/cheapo-lcr-t4-esr-meter-transistor-tester/

author: poot36
author_rank: Frequent Contributor
timestamp: October 10, 2021, 10:03:35 pm
content: I have got the replacement component tester and it is running actual code from that German websight not some cloned China knock off code. At some point I need to get the components to properly calibrate it but for the time being it works well enough for me to get an idea if the component is bad or not. The tester has the model GM328A on it from Geek Teches if anyone cares. Thanks for the help in trying to fix the other tester.