Burning EPROMS

Pinball machines use three types of programmable devices. By far the most common are EPROMs, used to store code, sound and graphics for solid state machines. They can be erased and re-used any times. Early machines use bipolar PROMs, devices that can be programmed only once. And many machines use programmable logic, with simpler devices (PALs and GALs) replacing a handful of TTL chips, and more complex devices carrying most of a video or sound subsystem.

For most people, programmers capable of handling mainstream EPROMs (2732 (32k) - 27C080 (8 meg)) are sufficient.

Willem Programmers

These programmer are the least expensive available. They all run using open-source software. The simplest systems run from the parallel port and an external power supply, and have a tricky configuration using DIP switches and jumpers. Upgrades to the basic devices include USB power (you still need the parallel port); USB interface and power; and electronic configuration.

Recommended True USB version $80 - 120

Pocket Programmer

Designed and built in the U.S., these devices have been the standard for the industry. Programs 2708 with an adapter.

Recomended: USB version, about $270

Wellon Programmers

Designed and made in China,these devices use programmable pin drivers rather than TTL to program the parts. This approach means that Wellons can program a wider range of devices than other programmers, including PALs and GALs used in the logic of many modern machines. This is the author's preferred device because of its flexibility and up-to-date software and drivers (Windows 7 64 is supported).

Recommended: VP280, $120

There are significant;y more expensive systems available that can program a full range of devices. However, these are unnecessary for most people, and the new low-cost programmer are just fine.

EPROMS

EPROMs are an obsolete technology, but were the standard for embedded code and data from the mid-1970s until the emergence of flash memory. They made sophisticated pinball systems possible, providing digital storage for code, sound and graphics. They work by injecting electrons into a charge storage area using a relatively high voltage. EPROM programmers must generate these voltages, which is why some early devices are not supported by all programmers.

Buying EPROMS

New EPROMS are very rare, but "pulls" - used EPROMs taken from obsolete electronic devices - are regularly available on eBay or from online sellers. The best pulls have been erased, tested, have had labels and residue removed, and their legs straightened. Expect to pay a little more for this service.

Erasing EPROMS

You don't have to have an EPROM eraser. But they are helpful if you need to erase some pulls that were not cleaned, programmed the wrong code, or want to recycle some parts. EPROM erasers use a short wavelength UV light to neutralize the charges stored in the EPROM cells. Cheap ones capable of doing a few EPROMS at a time are available for maybe $20. Much bigger erasers - used - pop up on eBay for about $50