Roberts RT-1
This radio came along with an Ultra U930 from a local auction. Despite being different technologies, though only four years apart, their restoration paths were quite similar.
This radio came along with an Ultra U930 from a local auction. Despite being different technologies, though only four years apart, their restoration paths were quite similar.
It was immediately apparent that the ferrite rod was broken and besides that it just plain didn't work. There was enough noise coming from it to show that there was at least life within the beast and there were neither AF11x transistors nor spam-cans to worry about.
I glued the ferrite back together and splinted it with bits of wood too. Somebody had previously tried to stick it but had got one of the sections the wrong way 'round.
I found a resistor on the track side of the PCB which was broken in half and after changing that it worked. It would only get strong signals though and needed to be on full volume to be at a 'normal' listening level.
It had several wax capacitors in it so when I was next ordering components I got replacements for these; I hadn't felt like using my more expensive and tricky to get high voltage ones I have in stock for proper radios.
The effect of changing these was miraculous as it was now much more sensitive and plenty loud enough with the dial only just off the stop. I was so impressed that I even went to the trouble of making a replica battery for it. It was designed to use a 6V PP8 but these are no longer made so mine contains four HP11s.
I glued the ferrite back together and splinted it with bits of wood too. Somebody had previously tried to stick it but had got one of the sections the wrong way 'round.
I found a resistor on the track side of the PCB which was broken in half and after changing that it worked. It would only get strong signals though and needed to be on full volume to be at a 'normal' listening level.
It had several wax capacitors in it so when I was next ordering components I got replacements for these; I hadn't felt like using my more expensive and tricky to get high voltage ones I have in stock for proper radios.
The effect of changing these was miraculous as it was now much more sensitive and plenty loud enough with the dial only just off the stop. I was so impressed that I even went to the trouble of making a replica battery for it. It was designed to use a 6V PP8 but these are no longer made so mine contains four HP11s.
The dial was also badly scratched but I managed to get a scan off the internet which a friend further improved. I then printed this out and glued it over the original.
All was well for a couple of weeks until it started cutting out just as if it had a loose connection. I was nowhere near it at the time and it wasn't on loud enough to be vibrating.
Over the next few minutes this got worse until it was off for more than it was one.
Following the "If in doubt blame a capacitor" rule I changed the two biggest electrolytics. All was now well, in fact better than it had been since I'd had it. One of these caps was the supply de-coupler so I bet it was that which was failing with an intermittent short circuit.
While I had it in bits again I made a better job of repairing the ferrite and it now gets regular use. It's handy for being portable and when it isn't worth warming a valve set up.
Over the next few minutes this got worse until it was off for more than it was one.
Following the "If in doubt blame a capacitor" rule I changed the two biggest electrolytics. All was now well, in fact better than it had been since I'd had it. One of these caps was the supply de-coupler so I bet it was that which was failing with an intermittent short circuit.
While I had it in bits again I made a better job of repairing the ferrite and it now gets regular use. It's handy for being portable and when it isn't worth warming a valve set up.
As an aside I was informed that this was a rare limited edition case-covering and that it was worth a bob or two. I have since come across the original Roberts Brochure which lists it along with the other case styles and the Roberts Group say that they are spread amongst the whole production run.
I don't think mine would fetch top dollar as it isn't in A1 cosmetic condition and its handle is functional but not authentic. Personally I like it as it looks like it's lived and I'm not in fear of doing anything to de-value it.
I don't think mine would fetch top dollar as it isn't in A1 cosmetic condition and its handle is functional but not authentic. Personally I like it as it looks like it's lived and I'm not in fear of doing anything to de-value it.