Serial number 716696
Pye T19D veneered wood case with sloping front £22.1s.2d plus purchase tax. Valve lineup: ECH35 EF39 EBC33 EL33 AZ31 Long, medium and 6 short waves Cambridge, UK 1950
The model T19D was introduced in 1949 and is similar to the 19D which was introduced 1948. I have two of these radios this one although clearly marked T19D the dial and cabinet are from a model 19D radio. As far as I can see none of the components have been changed and the radio apart from the switch replacement is 'as built', the main electrolytic smoothing capacitor is dated May 1949.
This is one of six radios which used to belong to the late Mr R M Nightingale given to me by his daughter. Roy Nightingale worked at Cambridge Instruments for many years. The radio was sadly silent when I got it, but he clearly repaired this set over thirty years ago because the packaging for the replacement valve which now contains the faulty one was still inside the cabinet together with this packing slip. I wonder if he ever sent them the 34p?
After removing the dust and cleaning the chassis, I soon discovered that the main on/off switch was not working but this was soon rectified with a dose of switch cleaner. Both dial lamps had failed and were replaced and a few woodworm holes were treated and filled. I then used my megger to test the HT line and the smoothing capacitors before replacing the valves and energising the radio at a gradually increasing voltage from my variable transformer. With along aerial and a temporarily connected speaker I could tune into some stations on all wavebands but the sound was very distorted and the volume control was ineffective. I naturally suspected the volume control and took it apart gave it a clean and put it back together. No improvement! I discover that the valve holder for the ECH35 has two broken contacts, could this be the problem? I removed the top cap (grid) of this valve and still no change. Eventually I remove the valve completely and find that it makes no difference, but when I inserted the ECH35 from my other T19D the radio sprang to life and worked as intended. I found a rather tatty but functional replacement in one of my boxes of spares and returned the former to the original T19D.
I had been in correspondence with Tony Noble who had purchased a T19D at auction for £5.60 which was operating at higher freqencies than indicated on the dial. He had done some retuning of his radio before discovering that there was an open circuit mica capacitor in the oscillator circuit. I wondered if by any chance the coils in the 19D and the T19D might be sufficiently similar for me to retune this radio to suit the dial markings. He performed some experiments on his radio and responded as follows:
"I set the dial on the 16m range at 17.8 MHz at dial position 44, moved it to 50 ready for 21.6 MHz on the 13m, and gradually screwed the core in, tracking the frequency upwards as I did so. I got only up to 19.3 MHz with the core fully in, so nowhere near 21.6 MHz - so I'm afraid it won't work. It would probably be much the same on the other ranges".
I think I will leave the set alone at the moment.
History of Pye see: www.pyetelecomhistory.org/
Schematic click here:
For more details and to view my other radio.click here