AlphaServer 4100

Not sure if this is 'classic' enough but I figured there are a few people here who might know the system much better than me. I have a AlphaServer 4100 that reached me in slightly rough but internally clean looking condition, it's not been run in a few years. First time I powered it up it it seemed to run through the diagnostics fine on the LCD panel at the front and finished up sat at what I assume was the text that has been programmed into the panel from the SRM (it looked like a hostname or something similar). I didn't have a terminal on the machine at the time so the panel was all I had to go on. I had to leave it for a while so I switched it of and switched off the mains. The next time I fired it up it got some way through the diagnostics and stopped on a message related to testing CPU 3 (the last of 4 numbered 0-3) and seemed to stop. I left it while I grabbed a terminal figuring it needed diagnosing via the terminal read-out. I powered it down, attached the terminal and powered it up and... nothing. The LCD screen sits completely blank, the terminal doesn't display anything apart from dumping a few characters of junk when I power it off. I have tried the following: - Removed all PCI cards. - Reseated all the cabling to the PCI backplane and comm's (serial/parallel) board including the LCD display connector. - Reseated all the RAM and CPU boards - Removed all but 1 CPU and 2 RAM boards (in slots ME0L and MEM0H) - Added a second CPU in case it - Checked the control panel cabling to the LCD panel - swapped the installed CPUs around to test at least 3 in 1 and 2 CPU configs When powered on, the diagnostic LEDs on the power management board look like this (top to bottom) 0 = on - = off * = scan at 1 sec intervals 0 0 - 0 0 0 0 * * * * All CPU cards have the following LEDs displayed 0 - 0 0 As far as I can see 2 LEDs are lit on the PCI bridge card (in the main) chassis (DEC's design failure means you can't actually see these directly) 0 0 I have followed through as best I can the diagnostic procedures in the User's Manual and Service Manual and neither have yielded progress or any obvious sign of fault, aside from the fact that I can't *find* the LEDs that are supposed to indicate 'POWER_FAN_OK' and 'TEMP_OK' on the PCI bridge adapter. If they are there they aren't on but I've no idea a WHERE they are. All three main fans are operating and seem to be shifting plenty of air, as are the CPU fans on the installed CPU cards. Other things that should be mentioned are the PSUs emit a constant 'bubbling' humming noise, but the power management board seems to thing they are fine, I'm a bit skeptical. I also had one PSU blow an input filter cap inside the mains input socket which was a straightforward fix and was replaced. Basically, I don't know the machine well enough to know what it might be. Any help appreciated. -- Mark Benson http://DECtec.info Twitter: @DECtecInfo HECnet: STAR69::MARK Online Resource & Mailing List for DEC Enthusiasts.