Customers repairs: GEC receivers

GEC BC5441, S/No NZ7708, Repair No. D148

 The set, introduced in July 1950 was in generally scruffy condition and hadn't been touched for many years. Two versions of the set were sold during the period 1950-52, the standard version and the "L" version for low voltage districts. This example is the standard version which used a set of valves developed in the 30s, comprising X61M frequency changer, W61 IF amplifier, DH63 detector/amplifier, KT61 output and a U50 rectifier. In this set a 6Q7GT has replaced the DH63 and the first two valves have low emission perhaps from cathode poisoning. This condition was improved by changing the mains transformer tap to 230 from 250volts. Performance was poor because of component degredation affecting the RF and AF stages. The cabinet is in poor condition where the varnish has cracked and broken up, particularly on the top and front of the set. A loud hum was present on signals.

I initially fitted a new 0.02uF AF coupling capacitor followed by a couple of capacitors in the AGC circuit. I then realigned the IF transformers and the oscillator and RF coils for each of the three wavebands. Resulting performance was then very good but for safety reasons I fitted a new mains lead with a 13Amp plug.

After removing the old varnish from the front and top of the set I treated it with stain to match the sides then polished it with linseed oil rubbed in with emery cloth. This not only gives a good finish but gives it an old fashioned smell. To prevent the oil from feeling sticky and coming off I buffed it over with a wax polish.


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