From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Failure, diagnosis, and repair of a vehicle's radio system.
| Identifier | ExFiles\Box 168b\1\ img277 | |
| Date | 6th May 1938 guessed | |
| -5- Report of failure of radio on 2-H-50. It was reported that the radio was not working and, upon examination, it was found that there were no signals. The receiver was removed from the car, and upon examination it was found that there was no H.T. coming from the rectifying valve, the fault was discovered to be a short circuit of the cathode to heater inside the valve. As the cathode is the source of rectified H.T. this short had caused a heavy current to flow through a resistance in the L.T. supply to the vibrator, and had burnt it out, also the heat from this resistance had melted the wax out of a smoothing condenser placed beside it and it was destroyed. A new rectifying valve was fitted and the resistance was repaired, a temporary 2mfd condenser was fitted outside the receiver and the leads brought through the case - upon testing it was found that the H.T. supply was now quite normal. The receiver was then thoroughly tested and it was found that the A.V.C. was not working properly. It had developed a delayed action with the results that if the stations were at all weak it was nearly impossible to receive them. A temporary repair was done to same which consisted of cutting out one of the anodes of the diode valve, thus reducing the A.V.C. and upon testing it was found that there was a considerable improvement in the signals and the rectifying of the delayed action. As there were no suppressors fitted to the car the interference was very severe, especially from the ignition section. A suppressor was fitted in the main distributor lead and a condenser fitted across the battery side of the coil to earth. The engine and chassis were then thoroughly loaded. Upon testing it was found that the interference was removed and the receiver working quite well. | ||