Restoring a Calcomp 565 plotter for use with my IBM 1130 system

SOMEONE DONATED THIS PLOTTER TO ME - IT WAS IN SAD SHAPE

The plotter had been damaged when something in a moving truck fell down and dented the drum of the plotter fairly severely. In addition, the prior owner had disassembled it for unknown reasons and it was given to me as a pile of parts and a partially disassembled jumble. It was also missing the solenoid that holds the pens. 

FRIEND OFFERED TO STRAIGHTEN THE DRUM BUT RESULTS WERE NOT GREAT

I got the drum back with the dent hammered out but the drum was out of round, with dips and bulges since the aluminum had stretched during the dent repair. It is not good enough to draw graphs on. It sat in the shop for a long time waiting for some inspiration on how to repair it.

Some years ago, a reader of my blog offered to 3D print a drum but that trailed off to nowhere. Again, I waited for inspiration. I have not yet developed a high confidence plan for a replacement.

Part of the issue is that the left and right sides of the drum have pins that mate with pin feed paper, so that the drum will pull the paper up or down as it rotates. Even if I found a source to make or buy a hollow aluminum drum of the right dimensions, I would have to recreate the pins. 

MADE USE OF THE PLOTTER TO TEST MY CONTROLLER CARD FOR THE 1130

As part of the successful project to build a card and connectors to upgrade an 1130 to add support for an IBM 1627, which is a relabeled Calcomp 565 or 563 sold by IBM, I partially restored the plotter to verify that a plotter would be controlled by my card. 

It took several hours to carefully assemble the parts sufficient to attempt the testing. I had first tested the power supply and found it working properly. I then used the manual controls on the plotter to test out movement of the drum (up and down), the carriage (left or right) and the solenoid to lower the pen onto the paper. 

SOME PARTS OF THE PLOTTER ARE NOT WORKING CORRECTLY

3I discovered that the carriage movement circuitry is not working properly. Neither the manual controls nor pulses from a bench test setup nor from the 1130 controller card would cause the stepper motor to move. The power transistors for the stepper motor remained holding just one coil active, ignoring any attempt to change the ring counter to select an adjacent coil. This will need to be debugged. 

The chart paper motors, which keep tension on the rolls of chart paper that is moving through the drum, did not move. They are both physically frozen in place - I suspect congealed lubricants are the cause.

I have to restring the cables for the carriage movement, although I also need the stepper motor working for this to matter. With that in place and once the stepper is working, I can check for solenoid power with the pen raise and pen lower commands. I am assuming this circuitry works properly but it has not been tested.

MISSING SOME PARTS

I was missing the 5/16-32 panel nut that holds the power on/off switch onto the panel. It is hard to find that size nut, as the retailing world seems to be concentrating on 3/8" and metric nuts. There are also quite a few screws missing from the pile I received, a mix of 4-40 and 6-32 sizes. I will fill in all the missing locations when I replenish my screw stock. 

BUILDING A PEN SOLENOID REPLACEMENT

The plotter has a pen holder with a solenoid inside that is attached to the top of the carriage. It will lower a pen onto the paper or lift it off. The holder from Calcomp had several attachments for different types of pen inserts. 

I came across a Calcomp holder and solenoid that was used for a cutter instead of a pen. It sat on the same plotter mechanism but was used to cut plastic, paper or fabric. Since its shape and functionality is identical to the pen version, other than having a cutter instead of a pen insert, it should be easy for me to work out a way to put a pen in the holder. 

NEXT UP - LOOK INTO THE ISSUE WITH THE CARRIAGE STEPPER MOTOR

When I have time in the workshop, in between higher priority projects or tasks, I will dive into the logic and figure out why the carriage is not moving with manual or interface commands. At the same time I will do a quick check to see if the flipflop for pen lower/raise is working and if the circuit is driving voltage when the solenoid should be activating.