Electronics > Repair
Damaged T4 transistor tester?
(1/1)
orbanp:
Hello Everyone,

I have a T4 transistor tester (the yellow PCB, with green graphics display, from eBay) that gives a reading without any parts in showing that there is a 43pF cap between 2 and 3.
I wonder if the tester is damaged? I do not recall the tester being zapped, though it could have happened without me noticing it.

I cleaned the board with IPA, and before the cleaning the 43pF cap reading was between 1 and 3, and if the ZIF socket was closed the reading was between 2 and 3. Very interesting!
I also did partially disassemble the ZIF socket, could not find any dirt or foreign matter inside the socket.

The no part reading on the tester is obviously erroneous. If there is no part, it used to say that there is no part inserted or an unknown part is there.
Other than this, the tester seems to measure parts normally.

Measuring DC voltages on the inputs 1 and 2 reads about 18mV, 3 reads 1mV.
I do have another T4 tester, yellow, etc, a bit younger, with different firmware, and it reads about 6mV on all inputs with no part.
Measuring a couple of BJT transistors the beta readings differ between the to testers by about 15% - 20%.

I might replace that Atmel 328P processor on the board, though removing that SM chip does not look too much fun.
In that case at least I could compile the software myself.

Any comment on the above?

Thanks, Peter
u666sa:
Remove ATmega328 and stick it into programmer (I used T48), reflash the firmware and try it. If not, buy a brand new MCU.

I bought mine here, it says page does not exists for me at the moment, but it might be accessible to you - https://aliexpress.com/item/1608634088.html
MCU is real. When buying on ali, make sure you getting the real deal, not fake chip.
Navigation
Message Index
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod