I purchased a T4 which arrived broken. There was no backlight at first, there was a "Testing.." text when the button was held down. Nothing would happen past that. If the button was released the tester shut down instantly. Seemingly randomly the tester would function for a couple seconds.
After flashing the chip, both the M and K version, with various configurations, sometimes it worked for a while, a full calibration went through but after the next boot, nothing would show up on the display. It *did* identify components correctly a few times, both resistors and capacitors.
The tester is totaled now. After applying 5V to the LM7805 regulator output, 1.5A of current was rushing through a SOT23 device and thus burning my finger.
Does anyone know what the three SOT23 devices close to the 9V input are? The silkscreen says 9014 and 9015, the print on the device is J6 and M6.