S/3 Model 10 Project Germany 2015

Early 2012 I received an email from Jochen telling m that he owns since 1986 a complete System/3 Model 10,
including two IBM 5444 disk drives, a IBM 5424 MFCU and the IBM 5203 printer.
The CPU is equipped with 16kilo (not mega or giga) bytes of core memory.
The system is completed with an IBM 5496 Data Recorder

It was fully operational in 1986 before it was disassembled and moved to a storage location.

In the late 1970's the system belonged to a company where Jochen's father worked as an operator.
They named it  "".  It comes from a German poem that start with: 'Kasimir der Weise spricht....'.
Someone in the company suggested to name the computer "Kasimir der Weise", they short it to "Kasimir",
put this name to the front panel and from then on the System/3 had its own individual name.

When the company replace this system, it was donated to the Jochen's school.
Jochen operated the system, but when left the schole no one remembered how to operate the
machine and they decided to remove it.
Fortunately they asked Jochen he wanted it. He accepted it the system with alot of material
like (empty) punching cards, disk cartridges, all CE manuals and RPG training documents.

In 2014 the system was moved from storage to a summer time cottage near Trier Germany.

Jochen goal is to make this system operational again and I offered him to help.
A date was set on 27 June 2015
Below you will find the restoration project blog.

Positioning and Assembly

First hurdle we had to taken was how to position the system in the room and not to block any doors.
After moving the CPU, printer and MFCU around a bit we found the right location.

Positioned for assembly

We bolted the 5203 printer to the CPU and installed the rear modesty skirt between the CPU and the MFCU.

Cable puzzel
Now we had to unravel all the cables coming out of the CPU.

After some sorting out and with some still readable markings (30 y ago) from Jochen we where
able to route every cable to its right location.
Routing cables   Routing cable   Routing cables
Routing signal and power cables from the CPU to the MFCU.

Reformating the Power Supplies

Just powering up an old system that has been in storage for 30 years is not such a good idea.
First all power suppliers where rewired from 220V to 240V.
Rewiring   rewiring
Rewiring the +24V power supply inside the MFCU and inside the CPU.

Before reformating the capacitors the load was disconnected from the supply and a variac was connected at the primairy side of the transformer.
Reformating the bulk psu  
Reformating the CPU bulk power supply and the  +60V power supply inside the 5203 printer.

Slowly the primairy AC voltage was increased until the nominal DC voltage was reached at the secondair side.
This was done for:
Powering up the CPU

The CPU was connected to the 230/400V 3 phase mains.
Nothing happend.  The Emergency Power Off  knob was pulled.
After restore the EPO knob we had immediately "TH CHK" and "PWR CHK" lights.
Check lights 
Sounds a bit strange, but this is as expected. The TH CHK is turned off after pressing the Check Reset button.

I turned on the system while Jochen was holding the EPO knob just in case.
Some smoke came out of the CPU.  Poweroff !
After some searching we found the smoker, a resistor on the -4V regulator card.
regulator card   5860519
       Broken                      Replacement
Please contact me if you have an spare -4V regulator card.
The IBM part number is: 5808959 -or- 5860519.

Here stops our project. 
I probably have this card spare at home, but at that moment not with me.
Back at home I found the schematics of this card. This is pure luck!
The chance of finding IBM schematics at component level outside IBM labs is almost zero.
A repair at component level of this card is now feasible.
Will be continued.

Core memory

The core memory might be a real problem.
BSM  This picture is from another
module. (32kb and also broken)

These modules where build by IBM Mainz and they used some foam between the core planes to route the cooling air throught it.
Unfortunatly this black foam turns into some sort of tar over the years and starts eating away the X/Y wires.
A quick inspection with an Ohm meter confirmed my suspicion and that Kasimir's memory module is unrepairable broken.
The only solution to this problem is replacing it with modern solid state chips. This is a project on its own.

End result

To get this system up & running again several problems need to be resolved:
  1. Working regulator card and see what happens when the power up sequence continuous.
  2. Replacing the core memory with a more modern solid state one.
  3. Some small parts are missing, but not essentail to get the system working again
Jochen 'operating' this system again after 30 years !