Roberts R24 AM-FM Transistor radio

s/n 19560


Roberts R24 AM-FM  light brown rexine covered wood case  with wood end pieces. Portable model with push button wave change selection, 9 volt (PP9 or equivalent) These batteries should provide about 80hrs of listening for 4 hours a day at normal volume. Frequency Coverage: FM 87.5-108MHz MW 522- 1620kHz LW 150- 281kHz. This model has 2 integrated circuits, 3 transistors and a 4 inch 8 ohm speaker. It was introduced in 1983 and continued being made until 1986.


 

When received the radio would not switch on unless the pushbutton was held in place there were no markings on the front panel, the clear plastic beneath the slots was detached and the red pointer was absent. I found a picture on the internet and used this to construct the paper reproduction shown above and glued this to the anodised aluminium faceplate and then coated it with "Klear" water based floor polish.

The on/off switch resisted several applications of switch cleaner so I resorted to wiring in the unused contacts on this switch. This involved cutting a track on the printed circuit and making another connection for two of the aerial coils which used one of the contacts. As an initial part of this exercise I shorted the terminals with a screwdriver blade and noted that there was quite a spark, presumably from the inrush current to a 1000 mFd capacitor, maybe this was the reason for the failure? The radio seems to work well enough without it in place.

You can expect to pay in the region of 30 for a second hand one in good condition.


Circuit board and internal power supply

This is one of two non working Roberts radios given to me by Sabrina Mitchell who said that they had served her well over her long married life and were just sitting in cupboards taking up space but could not bear to chuck them away!