We are finding that the main problem with Marconi equipment dating from the 1950s is failure of the non-electrolytic capacitors, most of which were made by TCC.
Leakage in these capacitors when used for signal coupling upsets the working conditions of subsequent stages and can cause damage to valves and other components.
The only sure way of ensuring long-term reliability of these pieces of equipment is to change every coupling capacitor without testing it first – even if it works today it will fail in the future.
Replacement with modern capacitors will ensure that the equipment works for years to come.
Other common failures are “Visconol” high-voltage capacitors used in EHT circuits and broken or failed valves.
Left: A selection of components removed from Marconi equipment.