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Valve Radio and Audio Repair Handbook by CHAS MILLER

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Chapter 26

Repairing battery operated receivers

Conventional domestic and portable types

The first thing the reader may well ask is how does one go about obtaining the necessary HT, GB and LT voltages now that the batteries used have long since ceased to be produced?

Taking HT batteries first, there are several ways around this, one being to make up your own from the small ‘PP3’ type 9V units connected in series. Obviously ten PP3s are needed for 90V while fourteen will make 126V, suitable for use in sets using the nominal 120V HT battery. Intermediate voltage tappings in multiples of 9V may be made as and when required. With intermittent use PP3s will last a considerable time, but if it is anticipated that a set will be used for long periods at ...

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