Bush DAC90A Table Superhet - 1950

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The Bush DAC90A is a four valve (plus rectifier) table model superhet with two wavebands. It was available with a cream or brown bakelite cabinet and was designed to operate from AC or DC mains. CAUTION! it is possible for the chassis to be LIVE depending on the orientation of the mains two-pin plug. It is advisable to make sure the neutral side of the mains goes to the chassis and put a reference mark on the plug and on the back panel.

The valve line-up is UCH42(Frequency changer), UF41(I.F. Amplifier), UBC41(diode detector and A.F. Amplifier), UL41(Audio output stage) all valves are by Mullard.

I found this set in a second hand shop in Leominster. It was looking in a sorry state but was complete, fortunately the dial glass was in good condition and had not faded as tends to happen with these models. The chassis was in fairly good condition and had obviously kept in a dry place, because it was not rusty. All looked well with the wiring and the insulation had not broken down on the cables. The mains suppression capacitor C22 had gone short circuit and on replacing this the set came to life with good quality reproduction. The reason for someone getting rid of this set quickly became apparent, the mains switch was faulty and only intermittently made contact. I temporarily bypassed the switch with two wires across the two poles of the switch, so that I could keep it going until I could find a replacement combined volume control and mains switch. The dial illumination lamps were missing, these are MES fitting, 3.5v at 0.15A.

The cabinet was restored by using very fine wire wool to rub it down and then finished off by polishing with brown beeswax polish. This polish gives a beautiful sheen and fills the small scratches in the bakelite surface. Finally the rubber mains cord was replaced with a good quality ribbed plastic cable, which does not look too out of place on the set. The Trader sheet for this set can be found here, the files are quite large. This set is an ideal first project for restoration, since quite a few can still be found and the sound quality is excellent. Try to avoid sets with cracked or chipped cases, since bakelite is not easy to fill or repair. Small cracks can be joined using super glue.

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