Disconnecting wiring bundles from sequencer box - part 1 disconnecting TB3 and TB2

WIRING IS MOSTLY CONNECTED TO TERMINAL BLOCKS INSIDE AND BEHIND THE BOX

There is a small terminal block TB7 inside the box which is only used with the small transformer T1, also inside, that generates the 24VAC used for EPO and power switches in the 1130 system.  Another terminal block, TB2, is used for internal connections such as to the relays, fuse holders, and so forth. 

There are terminal blocks outside, TB1 on the rear, outside, and terminal block TB3 on the left outside of the box. All AC voltages in the machine are controlled from here. Connections run from relay R3 inside to transformer T3 outside that powers the convenience outlets, and to transformer T2 outside that drops 230VAC to 115VAC for use by peripherals and the fans. 

The SMS card that implements the power sequencing is wired to the sequencer box. As well, TB3 brings the SLT logic voltages for sampling in the SMS card and passes the +12 and +48 through relay R2 inside the box. Finally, TB3 provides the power on reset signal to the logic.

Many peripherals are provided AC voltages through their power connector. These are wired from the cable connector panel and the SMS power connector panel into the sequencer box, either outside on TB1 or inside on TB2. 

DISCONNECTING THE 1442, 1132 AND 2501 POWER CABLES

Fortunately, the wires that bring power to the power receptables for the peripherals were on separate cables that entered a different hole in the rear of the sequencer box. They were undamaged by the mice and therefore can be used. This saved me from having to pull pins out of a connector and replace the wire.

TERMINAL BLOCK USAGE IS VERY DISCIPLINED WHICH AIDS DISASSEMBLY

The terminal blocks have pairs of screws for each position, sometimes with jumpers between adjacent pairs in more than two screws are needed. IBM has assigned the right side of TB2 and the top side of TB3 for wires connected to the bundles that pass through the box walls. This is very convenient because removing just one side of the strip frees up the bundle nicely for eventual removal. 

DISCONNECTING THE WIRES FROM TB3 THAT RUN INSIDE THE BOX

These wires from the top row of screws on the horizontally mounted terminal block TB3 go inside and join the main bundle running through the box. Eventually these are connected to devices in the box or run back outside through the hole in the rear. I was able to pull that portion of the bundle through the side hole and it is now inside the box with the rest of the bundle. 

DISCONNECTING THE WIRES FROM TB2 THAT RUN OUTSIDE THE BOX

The right side screws of the vertically mounted terminal block TB2 were connected to the bundle that was going to run outside the box. There were also wires from outside connected to the left side terminals 3 and 5, coming from transformer T2. 

I still have to disconnect the other end of the bundle going out the rear hole. Some wires in the bundle run directly to the SMS power connectors, and the primaries of transformers T2 and T3. Depending on the connection methodology, they get unscrewed or unsoldered. 

The connections to devices such as relays inside the sequencer box are also part of the big bundle - the wiring harness. I have to get these disconnected in order to free up the harness entirely. 

Eventually the wiring harness will be removed from the machine and serve as templates for the manufacturing of new bundles with the same layout and lengths.