These IC testers are very neat, but i don't think they are practical. My issue with these chip testers is you have to desolder the component off the board to test them. That kind of defeats the purpose. I mean you can test new ICs, but that does not seem very helpful.

If you have a locked up board, you desolder everything one by one testing??? That is not a good repair method. Most 74XX and a lot of 40XX ICs can be tested with a DMM on diode test, in circuit, looking for voltage drops or powered with a logic probe using truth tables. This is far less invasive (but not fool proof by any stretch). The 74xx and 40XX ICs are all super cheap, if you have to desolder it to figure out if it is bad, just replace it?

The CMOS RAM tester is much more practical since these ICs are often in a socket and are bad very often.

Andrew