The nwX287 is a Dallas RTC Chip Replacement - DS1287 / DS12887 / DS12B887 (using BQ3285) now updated to Necroware's v2!!!

v2 now offers a jumper (blob) to force the chip to Motorola mode or Intel mode if you want (otherwise defaults to Intel).

Battery (CR1220/CR1225) NOT Included !!!

Many old PCs use an solid IC for the management of the system clock, these integrated usually report the wording DALLAS or ODIN on the container. These ICs contain a non-rechargeable lithium battery inside for maintaining the DATE and TIME information.

Unfortunately these chips are not eternal and last about 10 years which for retro is an issue (but at least they don't leak!).

When the battery runs out, the device no longer works and can generate errors at boot or even fail. Furthermore, the backup battery is not replaceable. The entire chip must be replaced. These chips are practically unobtainable because they have not been used for decades, even if they are found it is likely that they do not work well because they are too old.

HERE IS THE SOLUTION TO THE PROBLEM !!!

This little electronic PCB replaces most of the above chips and integrating a slot for a standard button lithium battery makes the functionality practically eternal, simply replace the battery to restore a old PC for years!!

The BQ3285 chip used here is compatible with the following old chips:

• DALLAS DS1287 / DS12887 / DS12B887
• Benchmark BQ3287
• ODIN OEC12C887

Some examples of computers using these chips:

• Dallas DS1287 / DS12887 / DS12B887: IBM PC AT and later IBM PS/2 models, Compaq Deskpro series, Compaq Portable 386, Tandy 1000 series (especially later models), Various 386 and 486 motherboards in IBM-compatible PCs, IBM PS/1 series
• Benchmark BQ3287: Found in some Compaq systems, Various 386/486 PC clones, Industrial and embedded systems, as it was compatible with the DS1287 pinout, making it interchangeable with Dallas RTC chip
• ODIN OEC12C887: Used in Amstrad PC series, especially in the Amstrad PC-2086 and PC-3086, Some IBM-compatible PCs and clone systems from the late 1980s and early 1990s, Certain Compaq Deskpro and industrial PCs as an alternative to the Dallas RTC chips
• Hitachi HD146818P RTC chip which was not only used in many PC mainboards, but also in other devices and home computers like the BBC Master.

*For Dallas DS14285/Benchmarq BQ4287 replacement select BQ4285 in the extras otherwise stick to the default BQ3285 which works in most systems.

This part should be compatible with following RTC modules:

• Dallas DS1287 / DS12887 / DS12B887 (using BQ3285)
• Dallas DS1387 (using DS1385, untested so far)
• Dallas DS14287 (using BQ4285)
• Benchmarq BQ3287 (using BQ3285)
• Benchmarq BQ4287 (using BQ4285)
• ODIN OEC12C887 (using BQ3285)
• VIA VT82887 (using BQ3285)
• Hitachi HD146818P

(Tested on IBM PS/1 2011 before sending)