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.