Wireless of the Week - week 45

[Bruce MacMillan]

Originally Posted by David Dunlop

Answer is to solid state the two tubes, ie. 1N4009 diodes in salvaged octal bases...you do get high voltage showing before the rest of the power supply warms up and the voltage is somewhat higher than 540 but seems to work ok...I made these changes a long time ago (2004!) to both my ac supplies and they've been fine.
David

This is a good solution and many people add a dropping resistor in series with the diode to bring the voltage down to what it should be. This mod can also be done to equipment that uses selenium rectifiers. You'll need a gasmask when one of them fails.

I was surprised to find the problem with the 6X5 was known before the war. Zenith used them a lot and was well aware of the high failure rate. The same issue happened with it's little brother, the 6X4. It was used in the RS6 spy set.

The important thing is these mods are reversable with no changes to the original equipment.