This is reproduced here from the website of Dave Cushman G8MZY www.dave-cushman.net
I took over a somewhat sick repeater (29 March 1981, at a Sunday afternoon AGM) The repeater had a transmitter producing a few milliwatts and a receiving system that had been deafened by water in the aerial baluns and water dripping out of the bottom end of the aerial feeder. Some tweaking of the cavities 'by ear' of well meaning, but ill informed 'helpers' also rendered the system somewhat deaf.
I fished the TX out of the hole and was given a quick tutorial by Geoff G3TQF, the original builder of the PA, on what was wrong and how to put it right. When repaired the TX was soaked overnight at 20 watts into a dummy load and as no further problems manifested themselves I took the TX to the GPO 'radio interference' lab (who had better test gear than I did) for a full check on spurious emissions.
Back down the hole with a mountain of test gear and a flask of hot soup, ably assisted by some well equipped out stations that provided calibrated signals and the machine was back on the air. At the time that this work was going on some hash was found on the 12v DC busbars and I resolved to isolate 'LE from the rest of the LV system by means of filters.
The original Hexalator was minus it's case and lying in a dusty heap on the bench. Using an aerosol can of solvent cleaner, the dust was blasted off and when the volatile liquid had evaporated, the unit was encased in the plastic bag that my lunchtime sandwiches had been in. (Not the first time that Leicester's UHF repeater's bits and pieces had been protected in this fashion.)