I'm still here... not that you'd know it. I've been really busy back in the real world and unfortunately this site has been seriously neglected.

​I've uploaded some new manuals that Benedikt sent me - thank you for those.
​Slowly, the collection of manuals is starting to grow.
​I've got some COMET M5 manuals that I will scan and then upload when I've got a free week; they are rather large. I'm also getting other odd bits of information from kind folks and so I will do my best to get that all uploaded as well.

​If you are sitting on any 8870 documentation please think about me and all the other 8870 enthusiasts before you throw it away. There is so little documentation left and the majority of what is available seems to be here on my site.

Looks like my old scanner couldn't handle the workload and died mid-document. Anyway, a replacement scanner is now up and running and I'm back to scanning documents whilst watching TV.

I've just uploaded some German 8870 Micro 7 documentation.

This morning I reorganised the entire site. A lot of the pages I'd previously written weren't actually accessible or were difficult to find. Ohh come on, it was my first attempt at a website.

​Anyway, I went though everything and made sure that all the pages are now accessible... I think.
​
​Now, all of the information on this site has either been extracted from the scraps of documentation that I've got, from my failing memory or from information that readers have supplied. If you spot anything that isn't clear or just plain wrong, PLEASE let me know so I can correct it. None of us are getting any younger and if this information isn't recorded soon it may be lost forever.

​Likewise, if you've been squirreling documentation under your bed please let me know. I'll happily take it off your hands and give it a good home, or scan it and return it to you if that's your wish. Whatever I get hold of will end up on this site... eventually.

Happy new year to everybody.
​
​Once again, I need to apologise for neglecting the site. I just don't seem to have much time these days. Anyway, I've spent some time over the festive season scanning in manuals. It's amazing how simple it is to do whilst watching TV. I've added a BASIC manual (original English version) and a BASIC program tuning manual, again in English. I never knew this second manual existed. It's an interesting if not short read.

The next manual I will scan is the Micro 7 one I have.

The peripheral tier on an M25 can accommodate three devices. Slot 1 (left) is usually the SMC backup tape drive, slot 2 (middle) is for use by the disk drive, but the right-hand slot 3 seems to be multi-functional. It's usually empty, or has a floppy (8" or 5 1/4") installed. However, looking at the backplane in detail and inspecting the backplanes from the three machines leads me to think you can add a second disk drive. There are a few tell-tale signs to corroborate this too.

If you look in the above picture inside the red box, there is a connector. On one backplane I have, there is a "bridging board" plugged in here.

All this "bridging board" does, is connect all the pins on the left, to their counterpart pins on the right. This has the affect of connecting the right hand slot connector in parallel with the middle slot connector.

Also, the data sheet for the disk drive states that the highest drive number should have a termination resistor pack installed. This MUST be removed from the other drives.

The above picture shows the inside of one of my M25 disk drive enclosures. You can see the configuration switch highlighted centre-left. Below that is the resistor termination pack. But look in the top right corner of the picture - there is a blue resistor pack. This isn't connected to anything and the resistance is the same as the yellow pack. This is actually a storage socket to hold the resistor pack when it's removed from the disk drive. No idea how this drive ended up with two packs (probably had the disk drive exchanged at some point). Both my other enclosures have this blue pack missing. So it looks like you are supposed to remove the resistor pack if needed, and store it in the empty socket.

I've still not been able to get a second drive to work. CONFPROG seems to be configured correctly, but when I try and mount the second drive - "INSTALL 0.2" I get an error "DISC ERROR READING INDEX" and the system just hangs. I know the second drive works as it's just been formatted and had an operating system installed and will happily boot a system if it's set as drive 0.

I'm missing something... but I don't yet know what... yet.

I've previously stated that I've obtained three M25s over the last few years and number 3 pictured above is in a really sorry state. I've no idea what happened to it but it looks like it's either been dropped or a lorry hit it. You can see the crack down the top of the left-hand side. Also, both the top and bottom tier cages are bent. Amazingly the backplanes are intact and all the plates and disk drive were still working when tested in my main machine.

Anyway, this thing has been taking up valuable space so I thought it worth removing anything of value and scrapping the rest. Absolutely everything electrical has been removed including the fans and plastic plate-slot blanks. The outer shell will go to the scrap-metal people.

However, I have a second chassis that's in a perfectly serviceable state once it's been cleaned, so I've decided to construct a second machine.

I'll be taking pictures thought it's rebuilt process, but not during it's tear-down. This second chassis was absolutely filthy and mice had been living in it and I didn't fancy having to keep washing my hands to hold my camera just to take a couple of pictures. You will be able to view the re-build pictures in reverse if you want to see how to tear-down a system :)

As for what I'm going to do with it, it will replace my current chassis as I cut a couple of corners when cleaning it originally, and there are a couple of jobs that I wish I'd done.

Once this second chassis is up and running, I'll gut the first one for all the useful bits and either drop it on Ebay as just an empty chassis (at least it's clean), or off to the scrap metal dealer. Nobody except me seems to what this stuff anyway.

After pulling my hair out as to why I couldn't get a second port working, I posted the question to the Nixdorf group on Linked-In.

Quick as a flash Malone came back with some useful technical information about cable part numbers to use, which whilst completely different from mine I was still pretty sure that my wiring was correct, and also made a comment that the second ALME channel on the first ALME is reserved for the remote support connection.

I'm sure in the past I've used this channel for a normal VDU connection, however, it was worth a try.

He was dead right. So, another useful lesson learned.

Thanks Malone for the valuable info.

I wrote my first decent business BASIC program last night. Amazed at how much I'd forgotten but it slowly came back - working in Visual Basic for 20 years hasn't helped.

I wanted a routine to search through a specified list of files and look for pieces of text.

The LIBR list file contains all the *C (contiguous) files that are likely to contain German text that's used by the operating system. For example, I wanted to find where the machines original owner name was stored - In MESSAGES, record 147 for the record.

It was a fun exercise and a real blast of nostalgia. I really need to get a second terminal up and running as just having the one is a real handicap.

I've actually managed to repair a second terminal. Next I need to assemble a suitable connecting cable for it.

As an update to this post, I've been messing around all day trying to get the second DAP4 to work over an IHSS connection for I'm having problems for some reason.

I know the DAP4 works ok, because if I put a V24 card in it and connected to the master port channel on the ALME it works fine. I've tried a different ALME and it's not that.

So it's either a problem with the interface cards (and I've tried several) or the cabling but if it is I'll be dammed if I can see the problem. I'll have another go tomorrow if I get the chance.

I've been doing a lot of site updates over the last few days and I'm not finished yet. I've added a pile of stuff to the hardware page, especially under the tape and plates headings including articles on how to service SMC drives and attempt to repair a damaged tape. There are also lots of high resolution photographs of all the plates I have plus other technical information.

Still lots more to do so keep checking back.

Update...

The nice man from UPS just delivered my replacement SMC drive wheels that Tandberg so graciously gave me.

Looks like I know what I'll be doing over the weekend now.