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Well, well, well… Here we are again.
The final pieces of the puzzle have arrived and are ready to be installed. Unfortunately, I was hospitalized over this last weekend due to some unfortunate health issues, so nothing was done on the computer.
As everyone who has been reading my posts knows, my IBM 5150 Personal Computer is completely restored to it’s full capacity. No, I’m not going to repeat the specs; sorry. You can see my IBM 5150’s specs in previous posts. What I will fill you in on though is the IBM 5161 Expansion Unit for the IBM 5150 Personal Computer.
Calling the expansion unit rare is really an understatement. These expansion units weren’t all that popular at their initial release mainly due to cost. And when users found out that they could retrofit an IBM 5160 mother board, and other components into the 5161’s case to effectively make an IBM 5160 XT, many of the internals for the expansion unit were put aside, and eventually lost, or recycled, never to be seen again. Which brings me to the current state of my own expansion unit.
I had planned on building my own expansion unit by using an IBM 5160 XT case as a starting point, and a few “off the shelf” parts. Previously, a friend in the Vintage Computer Forums had given me a complete set of cards for an IBM 5161 expansion unit. These included both the extender and receiver cards required to connect the expansion unit to the host PC. For privacy concerns, I won’t give any names unless I have their complete approval. The point here is that the extender and receiver cards are so rare, they have become virtually priceless;especially the extender card.
By using these cards as a starting point, my plan was to install an XT power supply, a standard 8 slot 8 bit ISA passive backplane and the other components as needed. The backplane would be the starting point for the rest of the expansion unit’s build. However, things didn’t quite work out that way, as I had mentioned in another post. Another expansion unit became available for only $40.00 plus $22.50 in shipping! Let’s just say, it was a deal I couldn’t refuse. That price did not however include any hard disc drives, but it did come with the original MFM hard disc controller. Replacing the missing drives and upgrading the controller to a Winchester model cost an additional $65.00. So for less than $130.00 I had a complete working, and most importantly, an authentic IBM 5161 expansion unit. The drives I purchased were an original 10 MB full height MiniScribe, and a 30 MB Control Data drive which was removed from a Compaq computer of about the same time. The MiniScribe drive eventually decided that it didn’t like it’s friction bearing any longer and decided to quit, so I purchased another 30 MB full height Control Data hard disc, along with a 40 MB drive which I used in refurbishing an IBM 5160 XT. But that is another story for another time.
The expansion unit, using the extender and receiver cards, works great. The IBM PC is now completely dependant upon having the expansion unit available and booted prior to powering on the main PC. The expansion currently has twin 30 Meg Full Height MFM Control Data hard disk drives, coupled with a dual 9 pin serial port, an Intel 8/16 LAN adapter, and a 3Comm 9600 baud modem. Finally the receiver card is installed in the very last available slot in the expansion unit. This is as the installation was intended. Today, I opened the last box of parts needed to round out the compete setup: a brand new, still shrink wrapped Western Digital 8 bit MFM controller. The hard disk controller came pre-configured for the Miniscribe disk drive as drive “C”, and the Control Data as Drive “D”, so the installation was pretty straight forward. There is one area that needed special attention. Standard MFM cables are too short to install 2 hard disk drives in this configuration, so another friend in the Vintage Computer Forums assembled a completely new custom set of cables to accommodate the added length required for connecting both drives to the controller.
I worked with Ed Hall; our site admin, and computer expert, to finalize the completion of my system over a few days. Of course, a complete set of photos of the system build was posted to All Things DOS, and on our sister site on Facebook under allthingsdos. (That is correct, no spaces)
The last thing I wanted to mention here today is the cost. I got lucky, extremely lucky! The entire cost of my IBM system, including the IBM 5161 expansion unit, printer monitor, and all of the peripherals and upgrades came to only about $475.00. A lot of that was to cover the cost of shipping the various parts, and components.
One thing to remember: Don’t think you can just go to Google and get a vintage computer locally, (although you might get lucky), however, keep your eyes open. The very same system as mine recently sold for over 10,000 to a collector. Yes, that is correct; Ten Thousand Dollars. My system is not for sale though. However, if you have any questions regarding your own 5150 project, or if you happen to have or find a genuine IBM 5161 expansion unit, you can make some money.
Please contact me if you have any questions about what you read here. I’ll be more than happy to help you. If I can’t, I’ll forward your request to our computer expert for a resolution.
Thanks for reading everyone. Have a great day.