The stacker mechanism that collects cards after they have been read uses an oscillating part to nudge cards together. This is driven by a cam that is turning slower than the main mechanism, with gearing to reduce the speed. The stacker gear on the axle of the cam has 211 teeth on an approximately 3" diameter gear, which meshes with a perhaps 5/8" diameter gear on the main motor shaft.
The original part was constructed of a plastic which disintegrated with age, thus a replacement gear had to be fabricated. Experts at a museum in Europe had produced a design to be 3D printed, which I used. Because of inexact dimensions for 3D printed parts, the teeth of the new gear were not fully engaging with the teeth on the driving gear. Whenever the ramp of the cam is rising to push the nudger sideways, the resistance increased just enough so that the teeth skipped over each other.
Based on a recommendation, I picked up a rubber band of a suitable size to put around the diameter of the replacement stacker gear. This gave enough extra diameter plus some bite for the teeth of the driving gear, allowing the stacker gear to rotate smoothly and activate the nudger. I superglued the band over the teeth of the plastic gear.
REMOVED FEED PRESSURE ROLLER TO FREE UP BEARINGS
With a card sitting in the pre-read station, when the controller logic requests a feed or read of a card, it activates a solenoid to lever a pressure roller down onto the rubber roller underneath. The card is pinched between the rollers and given a push into the read station.
The pressure roller was not turning freely. I disassembled the parts, carefully oiled the sides of the roller and worked it free, then put everything back together. So far, we have the parts working correctly to move a card into some rollers at the hopper throat by moving picker knives at the proper time. The continually turning rollers in the throat moves the card into the pre-read station.
 |
| roller that didn't |
 |
| Solenoid to press roller down |
As the card leaves the rollers it slides rearward to come to a stop on a spring loaded bar that ensures the card is in the correct position for its future movement through the read station.
 |
| Bar at bottom |
WORKING ON PRESSURE ROLLER IN READ STATION TO ACHIEVE EASY ROTATION
As a card is fed from the pre-read station to the read station, it enters a narrow gap and comes into contact with continually turning rollers that will move it steadily past the photocells of the read station. There is a rubber wheel on the underside and a spring loaded pressure roller on the top.
Alas, the pressure roller bearings were also sticky. I added some oil and began to work the roller to get smooth movement so that it could uniformly move a card through the read station. I am not satisfied yet with the smoothness of the roller so I will continue to work on this next time.
 |
| Poor picture of sticky roller in middle |
OBSTRUCTIONS IN THROAT OF READ STATION
I tried to slip some paper under the read station, having it pulled by the roller pair above, but the paper kept stopping on something. I imagine this is dust, rodent hairs and other debris, but I haven't yet cleaned it out. There is no value in having the pressure roller try to move a card if the pathway is jammed.
SMALL CAGE FOR SLT CARDS SITS IN THE LOWER CABINET
The main circuitry in this cage deals with the photocells and the coils detecting the timing pulses. Amplifiers turn the light into well shaped pulses at two points within each card column, allowing the values detected to be compared by other circuitry inside the IBM 1130 controller logic. A mismatch is used to detect read failures. Other amplifier shape the timing pulses CB-1, CB-2 and CB-3.
BEGINNING INSPECTION OF POWER SUPPLY AND POWER BOX
Underneath the reader mechanism sits the power box plus a card gate with SLT cards and some connectors. Otherwise it is empty. The power box sits on rails and is not bolted down any way. Instead it can be lifted upward and the bottom swung over the rail upon which is sits.
The bottom of the power supply has rectangular notches that drop onto the red rail in the diagram above. The green flat plate at the top fits into vertical slits at the top of the power supply. Thus one can push the power supply up so that it nests all the way up on the green plate; this allows the bottom of the power supply to swing inwards over the red rail. Once it place it slides down to sit on the red rail.
I do not have schematics for the power supply nor ALDs for the card reader, which could slow my progress depending on how the top level testing works out.
 |
| Capacitors to check |
 |
| Transformers to check |
 |
| Diodes and relays to check |
 |
| Another view of capacitors |
 |
| multipole relay |
 |
| Motor contactor and switch |
My first restoration tasks in the power box will be:
- Checking for shorts
- Testing all capacitors
- Testing all rectifier diodes
Once the major parts seem good, I will remove fuses and isolate sections so that I can test each portion of the supply individually. This provides some of the voltages needed but the IBM 1130 itself supplies the +3, -3 and +6 voltages for the SLT logic through the cables into the 2501. The cables also provide the AC voltage that spins the motor and energizes the remaining local power supplies.
No comments:
Post a Comment