I finally had some time to pay attention to my rescued BeBox I found a few months ago. Although the motherboard was still in working order, the hard drives were on the verge of failing, the power supply was on the verge of failing, and the case fans were old and raspy. Those weren't too hard to swap for modern, efficient, quiet replacements—a modern ATX case still fits in the BeBox's AT form factor with an ATX-to-AT adapter and a voltage blaster in an ISA slot to provide the missing –5V rail.
However, the signature "blinkenlights", the LED display that rises and falls with the two CPUs' activity levels, was also in bad shape; one LED cell had gotten ripped entirely off the board, and roughly half of the remaining cells were burned out. Doing some testing on the board, I worked out that the LEDs are mounted on the board with their anodes oriented towards the left, and each LED is connected to a common +5V rail on this side. Each cathode is connected to a 100 ohm resistor that then leads to the PLAs which control the lights. I replaced the original cells with some 0805 green LED cells, which despite being much smaller than the vintage LED cells still fit the pads, and bodged the damaged LED's cathode pad from the nearby resistor. And now the blinkenlights shine in their full glory.