I removed the upgraded RAM (it is ECC, non-registered). The upgraded RAM passed the extensive POST checks, so I was sure that the issue was not the RAM. In any case, I removed the upgrades and the problem still repeats.
I tried your trick of using a standard USB keyboard and mouse with the serial console showing. Now the boot process does not continue to the OK prompt, but freezes while probing the PCI busses. It completes the following steps, but freezes after the last:
Probing /pci@1f,0 Device 7 isa dma floppy parallel power serial serial
Probing /pci@1f,0 Device 3 pmu i2c temperature card-reader dimm-spd
beep ppm fan-control
Probing Memory Bank #0 512 Megabytes
Probing Memory Bank #1 0 Megabytes
Probing Memory Bank #2 0 Megabytes
Probing Memory Bank #3 0 Megabytes
Probing /pci@1f,0 Device c network firewire usb hub device 0 keyboard 1 input
Probing /pci@1f,0 Device 8 sound
Probing /pci@1f,0 Device d ide disk cdrom
Probing /pci@1f,0 Device 5 pci
Probing /pci@1f,0/pci@5 Device 0 Nothing there
Probing /pci@1f,0/pci@5 Device 1 Nothing there
Probing /pci@1f,0/pci@5 Device 2 Nothing there
Probing /pci@1f,0 Device 13 SUNW,m64B
(blank: it freezes here)
I note that it did detect the USB keyboard; but it locks up. The keyboard is known to be good (I robbed it from my Ubuntu notebook).
Unplug the USB keyboard and reboot; here is the same section of the POST:
Probing /pci@1f,0 Device 7 isa dma floppy parallel power serial serial
Probing /pci@1f,0 Device 3 pmu i2c temperature card-reader dimm-spd beep ppm fan-control
Probing Memory Bank #0 512 Megabytes
Probing Memory Bank #1 0 Megabytes
Probing Memory Bank #2 0 Megabytes
Probing Memory Bank #3 0 Megabytes
Probing /pci@1f,0 Device c network firewire usb
Probing /pci@1f,0 Device 8 sound
Probing /pci@1f,0 Device d ide disk cdrom
Probing /pci@1f,0 Device 5 pci
Probing /pci@1f,0/pci@5 Device 0 Nothing there
Probing /pci@1f,0/pci@5 Device 1 Nothing there
Probing /pci@1f,0/pci@5 Device 2 Nothing there
Probing /pci@1f,0 Device 13 SUNW,m64B
Reset Control: BXIR:0 BPOR:0 SXIR:0 SPOR:1 POR:0
Probing upa at 1f,0 pci
Probing upa at 0,0 SUNW,UltraSPARC-IIe (512 KB)
Loading Support Packages: obp-tftp kbd-translator
Loading onboard drivers: ebus flashprom eeprom idprom
Probing /pci@1f,0 Device 7 isa dma floppy parallel power serial serial
Probing /pci@1f,0 Device 3 pmu i2c temperature card-reader dimm-spd
beep ppm fan-control
Probing Memory Bank #0 512 Megabytes
Probing Memory Bank #1 0 Megabytes
Probing Memory Bank #2 0 Megabytes
Probing Memory Bank #3 0 Megabytes
Probing /pci@1f,0 Device c network firewire usb
Probing /pci@1f,0 Device 8 sound
Probing /pci@1f,0 Device d ide disk cdrom
Probing /pci@1f,0 Device 5 pci Probing /pci@1f,0/pci@5 Device 0 Nothing there
Probing /pci@1f,0/pci@5 Device 1 Nothing there
Probing /pci@1f,0/pci@5 Device 2 Nothing there
Probing /pci@1f,0 Device 13 SUNW,m64B
Sun Blade 150 (UltraSPARC-IIe 650MHz), No Keyboard
Copyright 1998-2003 Sun Microsystems, Inc. All rights reserved.
OpenBoot 4.10.6, 512 MB memory installed, Serial #60065423.
Ethernet address 0:3:ba:94:86:8f, Host ID: 8394868f.
Skipping diagnostic script because diag-script = none
ok
When I unplugged the USB mouse/keyboard and rebooted, the Sunblade finished its boot process to the OK prompt. Its just that, without the TD signal asserted on the TTY, I cannot give it the next command to cause it to load the OS. I am almost convinced now that the motherboard is toast.
I tried your suggestion of plugging the monitor directly into the Sunblade (bypassing the KVM): nothing happened; the on-board video just is not functioning (I didn't check this when I first purchased it; I just used the serial console).
So the score card is: no video; no serial console; no USB keyboard/mouse.
I'll keep playing with it this afternoon, but I suspect that I'll be ordering another one soon. I don't have this kind of money. Does anyone want to make me a brother-in-law deal on a gently used Sunblade 150?