Repaired Prog Load button, cleaned contacts of Power switch and tested up to energizing the contactor

PROG LOAD SWITCH HAD A BROKEN SOCKET AND WAS WEDGED WITH PAPER

As I looked closer at the console when I was testing the Power on/off switch, I noticed some paper wedged into the side of the Prog Load button. The socket had been broken thus the button would pop up out of the socket when released. These sockets are a plastic piece that IBM used for both buttons and lights on all the SLT systems, with a single part that works for pushbuttons, toggle switches and lights. 

The left side of the console has two dummy light positions that have a blank frosted white part inserted. Since they would not be used and are held in place by the metal console plate, I swapped a good socket from one of the dummy positions for the broken socket from the Prog Load button. The button is now as good as new. 

POWER SWITCH CLEANED TO GET LOW RESISTANCE ON CONTACTS

I was not happy with the contact resistance of the Power On/Off toggle switch on the console. I had to remove it to clean it and get deoxidizing solution into the contacts. The switch is locked onto the plastic socket by a 9/16" hex nut but the gap between the switch body and the plastic socket didn't leave enough room for any tool to turn the nut. I even have some narrow IBM wrenches, but they were much too thick for the small space they needed to enter.

I went to the local Ace Hardware and while they don't carry any specialty very thin wrenches, they have cheap thin parts that come with grills, used by the staff when assembling grills for display. It was close enough to 9/16" and thin enough because of how cheaply it was made. It was perfect for loosening the hex nut and I soon had the switch out.

The switch was filthy inside the stem but I cleaned and deoxidized it, resulting in very good low resistance contacts in both positions. I reinstalled it into the console. 

EPO (RED EMERGENCY SWITCH) HAD BEEN PULLED, RESET

In my debugging this morning I realized that the EPO switch had been pulled out by somebody years ago, in a childish desire to pull on the forbidden switch. The EPO switch locks into position when this happens, but it can be reset with a screwdriver from inside the display pedestal if you know how. It is now in its normal position and conducting electricity just fine. Somehow I had thought that I tested the EPO yesterday but obviously I did not. 

TURNING ON THE POWER SWITCH ENERGIZED THE CONTACTOR

With the system circuit breaker turned on and a fuse in F5 to power the 24VAC transformer, the system was just waiting for the Power On/Off toggle to be moved to the On position. I heard a clunk and then a noisy contactor which delivered 230V to the majority of the fuses and other circuits inside the sequencer box. It also energized transformer T2 which will drop the 230V down to 115V to drive all the cooling blowers, but I disconnected T2 as I wasn't certain of the state of the blowers or what debris might be flung around if they came on. 

VERY NOISY CONTACTOR, NEEDS RODENT DIRT REMOVED FROM CONTACTS

Loud buzzing in a contactor is a sign that the armatures are not pulled fully against the 'on' stop. This can be due to inadequate voltage on the solenoid but also by debris blocking the armatures from fully sealing. The latter is the much more likely scenario given the rodent nesting that took place inside the sequencer box. I will remove the contactor and clean it up so that it will work quietly. 

RELAY R3 FOR CONVENIENCE OUTLET POWER FROZE UP AGAIN

The rust solidified again and is keeping the armature from moving on R3. This blocks application of 230V to the fuseholders F3 and F4 which feed the primary of transformer T3. That transformer drops the 230 to 115 and feeds power to the convenience outlets in the 1130 system and its peripherals. 

The relay switches 230V to the transformer primary with the fuses specified at 3 2/10 amperes each to support loads of up to about 735 watts in total on the convenience outlets. If I get a replacement relay, its coil should work with 24VAC and its contacts have to handle the high voltage and 3.2A currents, plus tolerate reverse EMF when the power to the machine is turned off by the circuit breaker or pulling the plug from the building. It should also mount in the footprint and area where the existing R3 fits. 

I won't spend the money on this relay until I am further along in the restoration and comfortable that it will be restored to full working order. At that point I can purchase a substitute relay and install it. 

Finished rewiring and initial testing of power sequencer and related circuits; a few minor faults found

REWIRING REMAINDER OF CONNECTIONS INSIDE BOX

I finished all the connections coming into the box, verifying each connection was to the proper destination as I went. The bundles sticking out of the rear and left side have to be connected outside the box to complete the rewiring. 

I did spot a troubling error in the machine's wiring for the 2501 card reader. The power socket for that device delivers 115VAC for the convenience outlets (and motors), using the same pins assigned to all power connectors. However, the pin normally allocated to the side we consider the neutral wire was hooked instead to the hot wire on this device only. 

Since the output transformer isolates the convenience outlet, the choice of neutral is somewhat arbitrary and does NOT include bonding to ground as is done with building power. However, this means that if equipment is used plugged into the convenience outlet of the 2501 and other equipment uses the 1130, 1442 or 1132 outlet, there will be 115VAC between the neutrals of the equipment. 

Some early equipment connected the chassis to the neutral wire, depending upon the building's bonding of neutral to ground for safety. As the machine sits, those older practices could leave metal parts at 115VAC due to the improperly wired 2501 power connector. 

WIRING TB3, SMS CARD CONNECTOR AND TB1 WITH WIRES FROM SEQUENCER BOX

While the laced bundle is a very reliable guide for which screw is connected to each wire, I double checked all destinations from the terminal blocks. This involved destinations on gate B power strips, inside the sequencer box, and terminals on other blocks. 

The SMS card had its leads pushed onto the bottom of the card connector. I once again used the continuity tester to verify that each pin of the card is connected to all the proper places in the rest of the machine. 

RAW DC POWER SUPPLY REMOUNTED IN 1130

I put the raw DC power supply back in the machine and wired up the primary power for it. I won't connect the destinations for all the DC voltages until I am satisfied that the output is good. While I did test on the workbench, this will check that with the jumpers and wiring for 230V, the output is still good.

 FUSES IN MACHINE DON'T MATCH THE VALUES LISTED IN THE ALD

In all cases, the fuse was either the correct size or mostly larger than the specified value. In some cases it was dramatically higher than the value designed for protection of the machine. I had some fuses in my supplies that were much closer, which I swapped with the incorrect fuses. I did order one 2A fuse because neither the fuses in the machine nor the spares I own are close enough for safety. This fuse protects the +12VDC and +48VDC power rails. 

INITIAL TESTING WITH POWER

I first checked that the circuit breaker did isolate everything in the machine from the building power. I then flipped on the breaker but did not insert any fuses. The only destinations fed power are the relay R3 contacts and the fuse F5 for the 24VAC transformer. Since R3 will not energize unless the 24VAC is present and the CE switch is on, the power did not pass through R3 to the rest of the machine. 

When I inserted fuse F5, the 24VAC was produced which technically would energize R3, thus feeding 230V to transformer T3 which produces 115VAC for the convenience outlets in all machines. Because R3 had the armature rusted in a fixed position, it was not closing the contacts. In any case, the contacts of R3 pass through fuses R3 and R4 before powering transformer T3, so power would have been contained. 

I tried to turn on the main contactor, although with all fuses except F5 out of the machine. This would deliver 230V to the power supplies and through transformer T2 would produce 115VAC to drive all the cooling blowers. It did not pull in, thus no power was passed along. I put a voltmeter across the coil contacts and saw 2.4V indicated. 

I did check continuity through the emergency power off switch and that the main power switch was working properly. When I next get to the workshop I will debug this issue, to see if the contactor is jammed, damaged or otherwise not working properly; alternatively there may be some other fault such as very high resistance on contacts in the path between T1 generating 24V and the contactor coil activating. 

Last lacing and start of reinstallation in sequencer box

FINAL LACING COMPLETED

IBM lacing is done so well that you can tell immediately which screw on a terminal block that each wire should connect to. The section that brought the wires to the SMS card (power sequence logic) is well laced enough that there is no chance of confusion. The wires run to socket connections A, C, E, F, G, K, L, M, N and Q, from right to left when viewing the socket from the side of the machine. The lacing separates each wire so that you can't mistake one for another. 

That set a high bar for me to match as I relaced the bundle. I worked hard to provide the same unambiguous exit of each wire from the bundle to ensure that connecting them to the terminal blocks will be quick and easy. 

It didn't look as good as the IBM work, but it did hold the wires together and get all the terminal rings at the proper point for attachment. 

TRANSFORMER T1 MOUNTED AND WIRED TO TB7

I mounted T1 on the left side of the box and connected the wires to the appropriate terminals on TB-7 on the bottom. It has the proper jumper set up for 230V operation. It is ready to go, providing 24VAC to the rest of the circuitry. 

BUNDLE PLACED IN THE BOX

The bundle of wires has groups of wires exiting through two holes in the box. One opening at the upper left feeds the wires out to connect to TB-3 which is a horizontal terminal block on the left outside of the box. The other opening in the rear feeds wires to TB-1, a horizontal terminal block on the outside rear of the box plus wires to the SMS card. 

The bundle runs from the top to the bottom along the left side, feeding connections to vertical terminal block TB-2 inside, then it splits. A section runs along the front panel to connect to the fuse holders and time delay relay. The remainder runs along the bottom of the box, connecting the contactor, TB-7 terminals and the circuit breaker. Another bifurcation delivers a small set of wires to the convenience outlet and CE switch on the right side of the box. 

The bundle them runs vertically up to connect the three relays mounted on a shelf, as well as passing out of the rear hole to connect to the SMS card and TB-1. With the bundle positioned in this way, ring terminals are available directly in front of each component or terminal block that needs to be connected.

CONTACT CORROSION CLEARED ON FOUR RELAYS

I used a burnisher and some deoxidizing spray to clean the contacts on relays R1, R2, R3 and the time delay relay TD1. I discovered that relay R3 had its armature rusted to the frame due to urine contamination. It wouldn't move down at all. I worked on it for a while and it is slightly better but this relay may not work. 

The relay feeds power to the convenience outlets when the 24VAC is on, even if the machine is otherwise powered down. The impact if this doesn't work is that the convenience outlets will be dead, but the rest of the machine will work properly. 

I can try to free up the armature later, or find a suitable replacement relay, or just wire around the relay so that the convenience outlets are always on when the circuit breaker is turned on, even if the EPO button (red Emergency button) is pulled out or the CE switch is turned to off. If I do the latter, then I would affix a big warning sign by the convenience outlet about the presence of power even with EPO and CE switch activation. 

MOUNTING ALL COMPONENTS AND WIRING THEM TO THE BUNDLE

All the parts inside the box are now mounted and wired to the bundle. The relay R3 is in place although it might not work as I mentioned in the paragraph above. The wire bundles are passed through the holes to connect to the SMS card, to TB1 and to TB3. 

TWO OTHER HOLES BRING WIRES INTO THE BOX

One hole at the bottom left side of the rear of the box delivers the primary power from the line filter (and building AC plug). Another on the left upper side of the rear of the box has wires which feed various peripheral devices with AC. These enter through the hole and are attached to TB-2 inside the box. 

I didn't finish connecting those wires to TB2. The power supply feeds are connected but the convenience outlet power to the 1132 and the 1442 are not yet connected, nor is the 115VAC for the peripherals that connect via SMS cards - disk drive and typewriter for this system. 

CAREFUL CHECKING WITH EACH CONNECTION

Every time I connect a wire to a screw or component, I beep out the connection to be certain that it is the proper wire. This takes time but is important so that I don't make a mistake that blows a fuse or worse. 

Beginning restoration of 1053 console printer

VISUALLY IT IS IN FINE CONDITION

All the tapes, belts, cords and other parts are intact, with no signs of damage. There is one very common broken part, the return cord tension pulley, which has a nylon part that cracks on almost every machine after this many decades. However, that is easily replaced and won't stop restoration efforts in the interim.

TRANSFORMING CEMENT INTO OIL

The greases and oils used in Selectric typewriters (and all IBM products of the 1950s, 1960s and 1970s), solidify into near cement with age. Coupled with that, the foam soundproofing insulation converts to dust, tar or both. 

There are two schools of thought about solving the cement issue. One is to dunk the entire machine in a solvent bath to dissolve away the old lubricants. The other is to use an extremely light oil and carefully manipulate every moving part to restore normal motion. 

The problems with the solvent method are twofold. First, the 1053 has solenoids, a motor and other parts that can be damaged by the solvents. The enamel insulation on windings, if dissolved, shorts out the component or impairs its operation. Second, the solvent might not completely get into the pivot points and other locations where the lubricants turned to cement. 

I have great success using Nye clock oil and manipulating machines, so I will use that method on this machine.

CARRIER FROZEN IN POSITION

The carrier was stuck in one position and wouldn't budge as I gently tried to move it leftward. The escapement, tab and backspace pawls were also frozen in position. I began to lubricate and free up those small parts and to work on the roller upon which the carrier moves at the rear. 

I succeeded in getting it to move left a bit, but I really have to work on the operational clutch and related parts first. I see the clutches triggering repeatedly which are trying to activate functions like tab, carrier return, backspace and so forth. I need those to settle down and sit at idle before I can do much with the carrier. 

Prepared demonstrations to use when 1130 lacks peripherals

THE CHALLENGE FOR 1130 SYSTEMS WITHOUT FULL PERIPHERAL COMPLEMENTS

The 1130 system software DMS (Disk Monitor System) V2 R12/R13 is designed for batch processing which was the predominant paradigm for mainframes at the time the system was offered. One would punch up decks of cards on a keypunch, stack them in the reader before and after other decks for other jobs, and the system would produce the output on a line printer. DMS ran from a disk drive inside the 1130. 

While the machine comes with a console printer (1053 typewriter) and keyboard, they were not the main interface between a user and DMS. While it is possible to print the DMS messages on the typewriter after reading in a // CPRNT card and one could even read in a // TYP card that would look to the keyboard as the source for the next 'card' records, it isn't practical. DMS and the languages had fixed formats for input which are pretty strict, so that typing in a program via the keyboard is unlikely to work out well. 

The compilers are not interactive and one cannot simply correct one statement and try again. If using the keyboard, one typo would mean you would have to type in the entire program once again. 

Most software, however, would not redirect output to the console printer from the line printer, it was only the DMS messages themselves that were rerouted by // CPRNT. Thus without a working line printer you would get nowhere even if you tried to laboriously type in each program and control card. 

Finally there is no way to start up DMS by booting the disk and have it begin reading from the keyboard as it would if // TYP had been read during a session. It always starts out attempting to print the DMS messages for the dummy JOB that runs as you boot the system. That requires a working line printer. If it had for some reason printed on the console typewriter, the next action of DMS is to read from the principle input device, a card reader and not the console. 

Most programs run on the 1130 read cards and printed lines, but a few would interact by typing on the console and reading the keyboard or console entry switches or both. To start them, however, you need a reader and a line printer for DMS to start up and read the // XEQ command card. 

SOLUTION - START A PROGRAM ON A SIMULATOR, FREEZE IT AND DUMP THE MEMORY

If we assume that we have demonstration programs whose operation does not require card readers and line printers, then we can use an IBM 1130 simulator to boot up DMS and start that program. If we freeze the running of the program at a suitable point, dumping the memory to a file, then when the file is loaded into memory at some future point, the program will resume where it had stopped. 

The 1130 systems I restore have a console loader built in, which will take a file in the format dumped by the 1130 simulators and load the real 1130 core memory with those contents. Thus, I can take the dump that was saved in the paragraph above, load it into a physical 1130 system, and it will resume operation just fine. 

As long as that program only uses the console printer, keyboard and console entry switches, and it does not request DMS to fetch any functions from disk to support its operation, it will run just fine. If the program ends and exits to the monitor, however, it will stop with a 'disk not ready' error as it tries to load another part of DMS to run the next job. 

MODIFYING DEMO PROGRAMS FOR A GOOD FREEZE POINT AND PERPETUAL RUNNING

I took several candidate programs that could run on an 1130 system without external peripherals and made a couple of modifications to each. First, I blocked the programs from ending, as that would go back to the monitor and stop the machine dead in its tracks trying to run DMS. Next, I set up a good freeze point that would ensure a good restart each time it was loaded into core and begun. 

DISCOVERING A FLAW IN THE IBM 1130 SIMULATOR

My method requires that I dump all of core memory. My restarted programs weren't working well if I cleared memory before loading them, and after some detailed debugging I realized that the 1130 simulator was not dumping all of memory to the file. In fact, it dumped only half the memory.

The flaw was in the code to do the dump, which set up a loop from address zero to a stopping point. The calculation for the stopping point took the memory configuration of the 1130, which in this case was 8K words, and divided it by two. 

I can see how this defect came about, because an IBM 1130 word is 16 bits, thus 8K words is 16K bytes. If the memory size had been recorded in bytes, e.g. a 16K machine would store its size as 32K bytes, then the logic made sense. However, the loop was reading entire 1130 words, not bytes, so it was stopping at the midway point in core. 

I am helping as a beta (or alpha) tester for someone who is building a really top notch IBM 1130 simulator. It does implement a dump of the full memory size, so I could use that simulator to accomplish my task. 

FIRST FEW DEMO PROGRAMS COMPLETED AND SENT TO MUSEUMS

The three programs which were original games from 1130 installations were NIM, Craps and Tic-Tac-Toe. I did the small modifications to each, ran them on the simulator and created my memory dump file. The museum can load core with one of those three files and when they press Prog Start, the program begins its perpetual execution. 

Loading core on an 8K machine can take close to an hour, so it is not practical to rapidly change demonstrations. However, a museum could change the program on a daily basis, for example, to give repeat visitors something new to experience.

WORKING ON A MUSIC DEMO

There were programs developed on mainframes of the 1950s and 1960s which would produce music on a radio held near the core memory of a computer. These typically read in a short deck of notes and durations from a card reader, or from a disk file. Neither of those are available for the purpose of a standalone demonstration, but I am going to modify the program to run entirely from memory.

Due to the limited core memory size of the museum 1130 systems - typically just 8K words - I have to select only a few of the dozen or so songs that were transcribed to drive the music application. I can allow the museum visitor to choose from three or four such songs and then hear the music playing with a handheld transistor radio. 

Repairing remainder of wiring bundle and preparation for reinstallation

CONVENIENCE OUTLET REPAIR

I removed the end terminal from the ground wire, put a green heat shrink tube to cover the scraped insulation, installed a new spade terminal and reinstalled the wire. The outlet is now repaired. 

SEQUENCER BOX CLEANED OUT AND READY TO PUT BACK TOGETHER

The thickness of the crust at the bottom of the box made the cleaning task much more difficult. The rodent excretions combine with the rust to form a layer that I have to slowly dissolve, scrub away and sometimes wire brush just to break it up. 

I wasn't able to get all the crust out, particularly in the rear of the box, since my wire brush can't fully attack the corners and edges. Once it was about as good as possible, unless I fully removed it and  submerged it in acid, I began to plan for the reinstallation and rewiring. 

IDENTIFIED ALL WIRES THAT MUST BE REPAIRED AT EXIT HOLE SITE

To make the task easier, I did cut some of the lacing allowing me to look more deeply into the problem area. I spotted one additional wire that had insulation stripped off and that was not obvious when tightly bound. 

The major AC wires were easy to trace down, remove and my newly fashioned replacements are laid in place on the bundle. The more challenging issue are the low voltage thinner wires that run between the SMS card and the relays and other objects inside the sequencer box. I see four cut wires and one that has damaged insulation, thus I will need to repair the five. 

One challenge is that the connectors that slip onto the SMS card are very oxidized with age and that makes them extraordinarily difficult to solder to. I can't find any modern replacements either. I needed to figure out a way to repair these wires since I can't replace the entire wire length as I did with the high voltage lines. 

Since the bundle is set up perfectly to connect to every terminal where it sits, with no excess wire length, I can't pull the cut ends together and solder them or the terminal spacing will be impaired. Once I was resigned to having splices with heat shrink, the repair went quickly. I cut back both sides and used some new wire as a bridge segment. Thus there were two solder joints for each repaired wire, with heat shrink tubing over each joint.

RUNNING NEW WIRES AND TEMPORARY ZIP TIE TO BUNDLE

All the new wires were bent into shape and run alongside the bundle. Yellow zip ties held them in place while I got everything shipshape. The plan was to remove the broken parts of the old lacing and the yellow zip ties section by section, then lace all wires together, much like this bundle was when originally manufactured. 

TESTING ALL CONNECTIONS

I sat with the schematics and beeped out every terminal connection to be certain that everything is connected properly. With every terminal properly wired to its other end, be it terminal or component, as long as I get each terminal on its proper screw terminal during assembly, the sequencer will be correct when installation is complete. With a well laced bundle, the terminals will be direction in front of their intended screw. 

RELACING OF THE BUNDLE

I grabbed my lacing cord and went to work. While a person can lace cord with a running knot for all the intermediate fastenings, if the cord is cut then it unravels through all those running knots. Instead, I took more time to make each tie tight even if it has to stand along, but the cord was continuous for long stretches. 

This is a time consuming task particularly with a large unwieldy bundle. I didn't finish by the end of the day but had a good portion completed. When I return to the shop tomorrow I should be able to finish the lacing and begin the reinstallation in the sequencer box. 

Disconnecting wiring bundles from sequencer box - part 3 - and commencing repairs

REMOVED THE FINAL COMPONENTS AND EXTRACTED THE BUNDLE

I was able to get the frozen screws on the contactor to loosen so that I could remove everything including the bundle. This I could put on the table and begin the repair work. 

Loose at last

As you can see, the sequencer box needs some serious cleaning before I reinstall any components or wiring. You can still see mouse bedding and the corrosion from excretions on the bottom 

INSPECTING THE WIRING TO DETERMINE DAMAGE AND REMEDIATION PLAN

I then cleaned and carefully inspected the wiring bundle looking for damage to the wires. I found a few wires with just a strip of insulation chewed off but the wire inside was intact; these can be repaired with heat shrink insulation. There were quite a few with more serious damage, even outright breaks in the wire. 

Wires chewed apart to improve rodent traffic flow through the hole

Several fuse holder had badly damaged wiring

Ground wire to convenience outlet was exposed

Serious damage on T1 primary wires

DEALING WITH THE T1 TRANSFORMER WIRES

The diagram for the transformer and the configuration chart for 240V power makes clear that some of the damaged wires are not needed for this machine. I chose to trim them and cover the end with heat shrink, as otherwise I would have chosen to find a new transformer as a replacement. This seemed to be an expensive alternative, but can always be done later if deemed worthwhile. 

Even more damage noted

Damage all to wire 1-6 side (primary)

I only need wires 1, 3, 4 and 6 for 230V configuration

REPLACING THE TERMINAL BLOCK (TB7) THAT WAS TOO DAMAGED TO USE

The block TB7 sat on the floor of the sequencer box, which exposed it to the acids of the rodent excretions. It was badly damaged and the screws holding it down were rusted in place. I chose to replace it with a new terminal block that is similar but not identical to the IBM part. My new block is rated for 600V and 15A, far above the requirements of the 24VAC transformer. 

My new block is slightly shorter, thus I had to drill and tap a new hole to screw down the replacement terminal strip. It is in place ready for transformer T1 to be wired to it and later the wiring bundle to connect here. 

REPLACING THE CHEWED FUSE WIRES

I cut and shaped new wire to match the damaged wires from the fuse holders. The old was pulled out of the bundle and the new temporarily alongside the bundle. Most had ring terminals on both end which made it easy to build them. One was soldered at one end onto a relay contact; I cut the damaged wire and left it on for now, with the new wire end routed next to the old. At a later point I will desolder the old and install the new wire. 

Damaged wire cut short and new wire end nearby

I used bright yellow zip ties to hold the new wires and the bundles together as I snipped away only a bit of the lacing. Once I have resolved all the wires that must be replaced, I will relace the bundle and remove these temporary ties. 

Twist ties preserving bundle until ready for relacing

I found a few wires with just a bit of metal exposed as the mice only removed a sliver of insulation. For those, I used heat shrink tubing rather than replace them entirely. I have completed the fuse end of the restoration. The convenience outlet fix will be minor and you already know how I am dealing with the T1 damage. The last big area to work on is the exit hole damage where there are at least six wires completely broken and insulation scraped off a few more. 

Fuses repaired, ready for reinstallation