Adventures with the Nixdorf 8870 Mini-Computer
  • Welcome
  • Contact Me

What to do with your new toy...

I'm going to cover some of the first steps you should follow if you've just come into possession of an old 8870. There are also links to articles that should be of additional help.
DO NOT JUST PLUG IT IN
No matter if the machine was recently working or not, don't just plug it, or any of the peripherals until they've been serviced. I know it's tempting but please, don't do it.

You may be planning on getting your new toy up and running immediately, or going to dump it in the garage to deal with at some future date. There are a few things however that need to be dealt with now, and you will be sorry if you put these jobs off.

It may already be too late !!!!!

The machine and terminals have internal batteries, and these batteries leak corrosive acid that will destroy everything it comes into contact with.

The main system will have a battery back-up plate installed and this need to be serviced immediately, and by service it could just be as simple as removing the battery and cleaning up any mess you find. Even if the battery hasn't leaked, it will. Remove it.
Details on servicing this plate can be found here.

Next you need to remove the processor boards from every DAP4 (or open up the chassis on the BA80s) and inspect for a leaked lithium battery. Below are some pictures of what can happen if it leaks.
The best thing to do is remove the battery using a pair of small wire cutters; the leads are really easy to cut, just make sure the cutters don't short anything out whilst you're in their poking around. Personably, I wouldn't bother replacing the batteries. All it means is you have to load the keyboard parameters which takes 5 seconds on a DAP4, but you can buy replacements if you want to.

Next you want to remove the SMC drive (if fitted).

Its 50/50 if the rubber wheel has perished already, but you don't want any more damage to occur.

It's possible the drive is secured with it's rear fixing screw. You can get to this via the hole in the back-plane directly behind the drive. They are usually unsecured however. Probably because they were so darn temperamental and always being exchanged.

You should service the SMC drive before attempting to start the main system. See below.

However, if this is a future project, remove the SMC drive and store it in the house. Place it someplace warm to allow any condensation to evaporate and then put it in a sealed plastic bag some place safe.

The other item to remove if you aren't going to be using the machine immediately is the hard disk drive. These don't like the cold and again, it's worth storing it in the house.

A word of caution.
If you do eventually manage to get the machine to boot, one of the first jobs must be getting a clean backup of at least the operating system drive. Don't rely on any tapes that came with the machine; they really don't age well.

The M25 will backup to (and restore from because I've tried it) XLP300 or DC600A tapes.

To get a backup you are of course going to need backup-tape media, and a working backup drive. There's an article on this site about servicing an SMC drive as used in the M25; probably the same as the Q40. The M15 drive is physical larger but will be of similar internal construction. M45/M75 or any machine fitted with an 1/2" mag tape unit will also need servicing.

If, and it's highly unlikely, but if you've come across a machine that uses removable magnetic discs then you really are going to need professional help. Please don't be tempted to run the machines till you've had them professionally serviced. The pyrotechnic display when the heads crash is stunning.

Ok, if you are planning on getting things working then it's time to service the machine.

You will find basic servicing details here.
(C) Joe Farr, 2011-2017