Two of the most interesting aspects of working with retro hardware are access to advanced documentation that simply wasn't available at the time, and the ability to improve certain components using much more stable modern variants. With that in mind, we come to the wonderful channel of Necroware, who took a retro Asus motherboard based on the Socket 7 and expanded its CPU compatibility by creating a custom module to obtain the necessary voltages.
The Socket 7 era was without a doubt one of the most attractive and entertaining in the history of computing. Its compatibility with processors made by different companies (Intel, AMD, Cyrix, IBM, IDT and Rise, all in the same socket!) puts it in a very special category, and its Super Socket 7 upgrade opened up the range of possibilities even more. Personally, I really miss a socket with the virtues of Socket 7, but I must admit AMD did a great job with the Socket AM4, supporting several generations of processors.
Computers based on the Socket 7 hold a privileged place in the retro world due to their enormous tweaking potential. The YouTuber known as Necroware is a true wizard when it comes to repairing and optimizing old hardware, but this time he decided to concentrate all his firepower on a retro Asus P/I-P55TP4XEG motherboard to accept Intel Pentium MMX processors. That includes creating a custom voltage regulator, manually defining multipliers using resistors, and other secondary details.
Hacking a 90s Retro Motherboard for Better Support
The full content is divided into two half-hour videos, but if you like retro hardware, you'll enjoy every second. The first video focuses on a general description of the motherboard, its compatibility with the proprietary Asus Media Bus technology, and something even more important: the possibility of adding additional voltages through an external VRM, and enabling the installation of MMX processors. Necroware also repaired the RTC module, but his solution had size problems (it was too tall and blocked the installation of an ISA card), and he replaced it with a battery and a custom PCB.
The video is full of technical information about the voltages compatible with Socket 7, and their specific requirements depending on the type of processor. At this point, Necroware started building the VRM... and ended the video on a cliffhanger.
Fortunately, the second part came a few days later, and although the VRM worked well, other issues arose. The motherboard needed a BIOS update (the UltimateRetro is ‘the’ place to get the BIOS for any retro motherboard), and we must not forget that Intel's official specifications define the processor multiplier differently for standard Pentiums and Pentium MMX. With a bit of datasheet archaeology, Necroware fixed this detail using a resistor.
In the final phase of the video, he decided to go to the extreme and install an AMD K6-2 400 MHz processor, compatible with Socket 7, but much more demanding in terms of voltages. Everything seemed to indicate that the VRM would explode due to the load, however, it managed to hold up maintaining an average of 72.8 degrees Celsius with active cooling. In fact, the processor is so fast that the BIOS can't even report the frequency correctly... but it worked perfectly. What's next? The original goal was successfully achieved (that is, adding support for Pentium MMX), but those K6-2s will need a more powerful VRM. To be continued...?
Necroware on YouTube: Click here
Source: Hackaday
