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Old 23rd Apr 2021, 6:45 pm   #1
Top Cap
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Join Date: Mar 2006
Location: Watford, Hertfordshire, UK.
Posts: 1,270
Default Roberts! - It's a bit late for an April Fool.

I just bought a Roberts R707 that was reported to be dead. Opening the back I found no battery clips and all supply wires were terminated onto a power input socket not shown on the circuit diagrams I have. So the radio needs an external supply but at what voltage? The circuit diagram shows 2 x 6V batteries in series to give 12 Volts. This seem very plausible because the voltages given are no higher than 12 Volts. But the descriptions I have read, call for 2 x PP9's to be installed! So I am in a bit of a fix here as I do not usually handle Roberts as I do not like their construction methods and their use of those 'orrible modules.
But I thought help was at hand because sitting in the middle on a steel base plate was a weird looking module. Perhaps this is a regulated power supply? Possibly rectifiers and smoothing to take an AC input?
The box looked very small for that but I decided to remove it for investigation, after all maybe this was why the radio was non working? Now this was not too easy as it is held in place by three metal 'twist' posts which were very difficult to untwist. When I eventually removed it and saw what was inside the mystery box, I very nearly fell off my workbench chair. It is just a piece of wire, presumably a fuse, with no indication of rating! But what an incredibly stupid idea to make an enclosure like this. A simple in-line fuse holder of the type fitted to car radios would surely have done the task or maybe it was the cost of the fuse that forced this crazy design. Talk about a late April Fool Joke!
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