grundo

The Motorola Net6200/166 ??? (TODO: Paste the research Purple helped with)

Specs

Processor: 2x PowerPC 604e @ 166 MHz
Memory: 8 72-pin SIMM module slots
Hard disk: Seagate BarraCuda 4 Series 4.29 GB 7200RPM Fast Wide SCSI 1MB Cache
Display adapter: Cirrus Logic GD5446 Rev A
VRAM: 2 MiB
Ethernet adapter: ZNYX NetBlaster ZX345 (SA0025)
SCSI card: Adaptec AHA-2940UW
Expansion: 4 Conventional PCI slots, 3 16-bit ISA slots
Clock battery: Duracell 3V DL1/3N (one-third N)
Serial number: MP00176
Motherboard label: MLU, LX SERIES 01-07582-03 (FIREPOWER SYSTEMS INC), serial LXM01113

The motherboard is labeled Firepower Systems, Inc. instead of Motorola.
When the system was first powered on, it booted enough to give a "no RAM" beep. Later attempts did not give a beep. There are four diagnostic LEDs on the board labeled A, B, C, D. When booting with RAM, light A stays on. When booting with no RAM, light C stays on. When booting with no processor card, no lights stay on. The beep no longer happens. Purple believes this may be due to the capacitors no longer being able to function properly and only managed to work for the initial power-on before becoming useless for further attempts.
After recapping, we discovered that when COMM 1 is attached to serial at 19200 baud, the system prints "AbcdefgBCD", first the first seven characters, then a pause, then the last three. Sometimes, it gets to "AbcdefgBCDE" after a second pause. Sometimes, there is a garbage character instead of this 'E'. Our hypothesis after this was that the machine doesn't like non-ECC RAM.
After installing two sticks of EDO ECC 60ns RAM, the machine finally boots.
The machine cannot be run without a keyboard. It will read garbage off the keyboard port and endlessly try to interpret invalid Forth commands, as seen from the serial console.

2023-09-09: The computer is purchased at VCF Midwest.
2023-09-10: The computer is temporarily transported to my parents' place.
2023-09-28: The computer is transported to the new home.
2023-12-16: 📈 The clock battery is replaced. Before replacing, it was measuring 2.9 V.
2023-12-16: The capacitors on multiple components are identified as bad.
2024-01-14: 📈 21 capacitors are replaced (8 on processor card, 13 on motherboard.