Tauntek IC Tester (Patreon)

I did a quick build of a Tauntek IC Tester. This is designed by subscriber Robert Grieb and was brought to my attention by Josh Dersch who used it to test all the ICs on the Digibarn Alto. More info at:

http://www.tauntek.com/LogICTester-low-cost-logic-chip-tester.htm 

It is sold as just a board and two pre-programmed PIC microcontrollers, so you start with just this:

It's up to you to buy the components from the well documented BOM.

It is definitely old school, and interfaces via RS232 to a terminal emulator. But it is super simple to use. Type LS112 to select a 74LS112, and T to test.

As you can see it gives you a ton of info besides pass/fail: power consumption of the chip, voltage values of the high and low logic levels, even pins with potential shorts to Vcc or ground.

Here is a chip that we previously pulled from our HP 9825, with one gate that failed (this is Ken's famous penta inverter).

This is neat. That said I also gained a new appreciation for my TL866 EPROM programmer, which you see on the left in the picture. In addition to being a very good (and unbelievably cheap) programmer, can also test TTL chips! Which I did not know until you guys told me in the comments! It is more terse, but does a good job in general. However I had a chip that failed in the Tauntek and passed in the TL866: it worked logically, but its power consumption was 10x too high, which only the Tauntek alerted me to. 

Many thanks to Robert Grieb for his thoughtful design. I plan to put the Tauntek to good use for the next debug session of the HP 9825 keyboard board.

Marc