WHEN THE SET JIBS.

Shannon News, 14 June 1927, Page 4

WHEN THE SET JIBS.

A valve may fail, as they have a nasty habit of doing at inconvenient times, and if you are a single valve user all hopes of further reception must be dropped unless a crystal is connected - across the aerial tuning circuit (writes the wireless contributor to the “Liverpool ‘Post’). In the case of a two or three-valve set, however, do not despair right away, but let us see what can be done. Whdre L.F. valves are employed disconnect the leads running to the primary (p) terminals of the L.F. transformer, and substitute your telephone for the transformer. You lose a valve for reception purposes, but that is bettor than no reception at all.

Where a lI.F. valve is used, remove the H.F. transformer.or anode coil, and make a temporary connection between the aerial terminal and'the side of the grid condenser, which usually connects to the anode coll or transformer.

These remedies- are, of course, for sets without any switching arrangements, and providing one valve is left for detection purposes you need never be entirely without a receiver of sorts.

Trouble from the batteries failing is more due to lack of foresight than a vagary of the set, and no temporary remedy ig available for this defect (?).

Fixe>d condensers often may be the cause of reception failing suddenly, especially in the case of the grid condenser; and if another is not available, viz:— Substitute a spare variable condenser or Make another fixed condenser. The latter may sound a formidable proposition, but it is really quite a simple matter to rig.up a temporary fixed condenser. All you need is some tinfoil off chocolates and some waxed paper (at.a-push, thin close-textured paper impregnated with candle grease). Cut two strips of the tinfoil about 2-sin wide, and Sin long, and, separating them with the, waxed paper, allow the foil to overlap for about 1 1-5, the ends left out being for connecting up. „ The paper and foil may be clamped between two pieces of ebonite or gummed together, and the whole wrapped round with insulating tape, a" temporary grid condenser then being made. If the grid leak is the cause of the trouble, a solution is easier of access.

All that is needed is a small piece of ebonite (say ljln by"Jin) with a terminal at either end, a groove scratched between the terminals, and a fairly soft lead pencil. Rub some graphite off the pencil under each terminal, and the surface of the ebonite round about before tightening. Some of this will have lodged at either end of the groove, and, after connecting this “gadget” in place of the usual leak, rub the pencil along the groove until signals are normal. It may even be possible to join the terminals on the grid condenser with a similar graphite line, this being even a simpler remedy. You may be troubled with faulty connection in a pair of ‘phone leads, caused by tho constant chafing having broken the strands of the flex. If some ordinary lighting flex is available it is quite a simple matter to make new leads. Some lighting flex should always be kept oh hand, for it is useful in many ways, a length of 25ft. to 30ft enabling the loud speaker to be taken into another room without disturbing the set.