Gisborne TMX – Part 3

Maintaining the manual toll boards of the 1970s was moderately labour-intensive. Installation obviously involved considerable labour, as circuits were hard-wired to modules which were repeated at regular intervals around the board. However, once installed, the various components were highly reliable considering the mechanical forces involved in day-to-day operation.

In the case of the Gisborne TMX (Toll Manual Exchange), maintenance consisted of routine testing of functionality, and preventative maintenance of components that were known to develop problems while in service.

The flexible call cords, used to connect the two parties for a conversation, required the most maintenance. The plugs at the end of the cords used three brass connectors to make the electrical connection, and were very similar in size and shape to the three-wire stereo headphone plug familiar to stereo enthusiasts of the time.

Unfortunately, brass has a habit of tarnishing, so cord cleaning was a regular maintenance task – often parceled out to the trainee technicians. Arriving in the toll room on cord cleaning duties would elicit groans from the operators at the positions scheduled for maintenance. The operator would have to move to a new position to continue processing calls, and an adjacent operator would have to monitor the calls in progress on the maintenance position and progressively disconnect them and process the toll tickets as they finished.

Cord cleaning involved applying a mildly abrasive cleaning paste to the brass plugs with a piece of rag and then polishing them by hand or with a motorised buffer unit which ran off the 50 volt supply on the toll board. The cords were then tested to make sure that they weren’t noisy due to frayed wires and were operating electrically.

The cords themselves contained three multi-strand conductors in a flexible fabric outer covering. They were about 1.5 metres long, and were threaded twice through weighted cord pulleys that hung suspended behind a kick panel in front of the operator’s legs. Cord replacement was reasonably straightforward, but involved a certain amount of diplomacy in protecting the modesty of adjacent operators.

One favourite trick for technicians was the cord eruption. This required a bit of stealth in quietly removing the covers at the back of an occupied toll position and a certain litheness to reach through to grab the cords from below the operator’s table. A quick thrust upward caused the cords to erupt out of the table in front of the operator like a pit of rabid vipers.

In my day, this trick was best reserved for the Saturday maintenance shift when the toll manager was absent from his lair, a friendly supervisor was on duty, and a favourite operator was the target. Miscounting to the wrong operator position usually resulted in shrieks of horror and a thickened ear, but was still satisfying provided management weren’t upset.

Fault repairs sometimes involved carefully removing a multiple strip to replace a worn jack or resolder a broken wire. This wasn’t too bad on the more modern Gisborne toll board, but it was a technician’s worst nightmare on the old shutter manual boards at Ruatoria … but that’s another story.

Lamp replacement was a breeze. The label strip covering the front of the lamp was removed, and the long slender lamp was withdrawn with a pair of special lamp tweezers. Over-zealous trainees soon learnt the amount of pressure required to grasp the lamp without cracking it – a cracked lamp turned a 1-minute job into a 5-minute exercise in near-dentistry using needle-nosed pliers. A particularly careless and unlucky trainee could turn a cracked lamp into a fuse-popping experience but, once again, the technique was quickly learnt – the hard way.

There were manual toll boards all over New Zealand in the 1970s. I was lucky enough to see the Wellington Toll Board in its dotage late in the decade when STD (Subscriber Toll Dialling) was being introduced across the country. The new Wellington Toll Room was already running its cordless NEC consoles, and the remnant of the old toll board stretched around the outer wall of the “old” wedge-shaped Telephone Exchange in Stout Street. The whole place was in darkness, with partially disembowelled toll positions spilling out onto the floor. Mysterious lights flickered at various locations and the odd 50 volt relay clacked away here and there. It was a sight that nearly brought a tear to the eye of the old “mechanician” who was my guide.

Standing there in the torchlight looking at the old toll board which stretched away into the gloom we were certain we could hear the odd whispered “Tolls here” from ghostly operators who’d laboured away at the boards in their heyday.

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