GB7WB Fan Control Thermostat Modified & Fitted.
The thermostat we had only had a ‘normally-closed’ contact and we needed a ‘normally-open’ contact to put the 24v fans on when ever the repeaters got too hot.
With three FX5000 repeaters stacked on top of each other, with their six combined crystal ovens and three power amplifiers etc you would be surprised just how hot they get!
A grub-screw was removed which was fitted to provide a rest for the center contact of the bi-metalic strip. A small screw with a solder-tag and wire was used to replace the grub-screw and the wire was attached to the spare solder post.
Now we have a single-pole, double-throw set of contacts and the fan switches on when the temperature rises.