Intel SBC-640 Multibus PSU schematic needed

[P-man]

hi all,

Just picked up an Intel i660 (Multibus) chassis with a bunch of cards but the psu is bad. I am figuring it out, but would be nice to have a schematic.. seems like my chassis/PSU is from 1978 but the rest of my SBC cards are from late 1984..

any hints appreciated!

 

[jonhales]

The relevant Intel manuals are 9800505-04 "iSBC 660 System Chassis Hardware Reference Guide" and 9800803-03 "iSBC 640 Power Supply Hardware Reference Manual". I'll get these scanned and will send a link to PDFs via a Private Message. It would be good if you identified the cards you received and dumped the ROMs.

 

[P-man]

hi Jon,

Thankyou for the schematic for the PSU though that will be a help! Currently i have a bad 171-1 transistor on the -12v rail. On removing the others to service the rest of the psu board i found the other two measure differently from each other as well. Do you know if a more easily obtainable cross for these? I have thousands of T03 transistors, but none of this type (schems say 12505-2) any ideas?

I made another thread with more system info..

 

[P-man]

For anyone reading this in the future - after looking at the schematic and what it was doing in-circuit I figured a 2N3055 would work in its place, and indeed it does now work fine replacing the 171-1 transistors