Chip Tester Knows if Your Old Chips are Working

Chip Tester Knows if Your Old Chips are Working

[Noel’s Retro Lab] has looked at retro chip testers before, but in a recent video you can see below he’s looking at the Chip Tester Pro, a preassembled chip tester for vintage chips, especially those used in Commodore computers. The device looks good on the surface with a form factor like a calculator or cell phone, an LCD display, and a 48 pin ZIF socket.

The user interface is pretty simple. A rotary encoder and a big red button are about it. However, there are also some headers where you have to use jumpers to wire signals to the chip. The firmware gives you specific directions, but it is reminiscent of programming old punchcard machines with jumper wires. Luckily, it looks like you only route the power to the device so you don’t have many wires to connect (usually two or three).

The tester is shown detecting a bad DRAM chip. The device can test logic gates, although it failed on some 7438s. We wondered it is because it would not handle open collector outputs, but we don’t know that. A firmware fix, however, allowed the parts to pass. It can test things like 555s and some non-Commodore chips like custom chips for the ZX-81. Test parts that require a non-5V supply won’t work since the tester has only a 5V supply. However, there are some common chips that have other supply voltages that you can test. But those are special cases because they function well enough to test without the additional voltages.

At the end of the video, you can see that the tester claims to work on chips in circuit which is notoriously difficult. Turns out, this only works if you can prepare the board by removing certain key chips. The procedure also disables some bus drivers with jumper leads. However, the demonstration didn’t work. It wasn’t clear if it was a problem with the tester or the setup.

Overall, this seems to be one of those niche products that, if you need it, is a bargain and if you don’t is probably not worth the price. [Noel] has some other chip tester reviews on his channel, as well, and maybe one of those would fit your needs better, but they are probably all not something everyone will need.

If you want something cheaper that you can modify to suit your needs, this homebrew tester might fill the bill. If you prefer to test discrete components, those testers are now dirt cheap.

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