June 2, 2019

MiniFrame Parts Found!

Vintage 1984 Convergent MiniFrame motherboard, 512KB RAM, 10 MHz Motorola 68010

Below are the seller's words, directly from his auctions.  Too bad, I private messaged him, to tell him I would have gladly bought a fully assembled MiniFrame and gone to his location for local pickup.  Another one of these rare machines (partially) bites the dust...but we'll save and resurrect what remains!

Motherboard from a Convergent MiniFrame Unix PC from 1984, 512KB RAM, Western Digital MFM controller, dual serial ports, 10 MHz Motorola 68010 CPU.

Here is the motherboard from a 1984 Convergent MiniFrame, which was a Unix tower designed by an important company which in 1988 became the network systems division of Unisys.  Convergent Technology helped develop the smaller but similar AT&T PC-7300. 

The person who found a Convergent MiniFrame for me in late 2017 didn't think anyone would pay shipping for a the large heavy case and power supply, so he removed the motherboard, memory cards, cluster board and 69MB Micropolis MFM hard drive only, discarding the rest.  I have no way to tell if this is working or not, but it is an interesting and hard-to-find piece of hardware from 35 years ago.   It is easier to find online documentation about the Convergent MiniFrame than it is to find parts of one.  I am happy to answer questions to the best of my ability. 

The processor is a socketed 10 MHz Motorola 68010.  There are also sockets for the Western Digital hard drive controller chips, Intel D8724 serial controller, AMD P8253 programmable interval timer and 41 more socketed chips.  The onboard RAM consists of 72 soldered-down NEC 64 kilobit DRAM chips (512KB total).   The 100-pin header and large metal rectangular support are for memory expansion and I/O cluster boards (which I will list separately on eBay).   One edge of the motherboard has two 20-pin headers and one 34-pin connector for cabling for two hard drives.  There is also a 34-pin connector for a floppy drive cable.  The back side of the motherboard has two female DB 25 ports labeled "Channel 0" and "Channel 1" (serial ports for terminals?) and a parallel printer port plus a DB9 female connector labeled "Cluster" which is for attaching one of Convergent's RS422 terminals.

2 Vintage Convergent Technologies Miniframe 512KB RAM cards + Ethernet board

2 512KB RAM expansion boards and an RS422 Cluster board from a 1984 Convergent MiniFrame Unix PC from 1984