Two Roberts.

[geofy]

This is a bit of a vintage repair in itself but I thought it might be of interest. In nineteen ninety my local town still had a full time fire-station, long since closed down now we all have smoke detectors. And they held an annual jumble sale. While digging through the junk, I saw an opened up Roberts radio which turned out to be a R200, along with a Roberts Rambler. I paid forty pence for the two!

The R200 had a dirty and marked dial perspex, but the controls still had their brights and the badge was still intact, any damage was done on the jumble stale, slight dents in the front and the badge chrome scuffed. It also didn’t work. After some testing with a multi-meter I found the second IF to be faulty, no surprise as it was an AF117. I replaced it with another AF117 using the sleeving from the old one (it was all I had then and I wasn’t really that aware of the trouble these transistors could cause at the time). I took the dial cover off and cleaned it with Dynacut and foam cleaned the knobs, an air duster was used to clean inside and dust from the speaker removed, the dents where cleared as best as possible though not completely. And the blue case foam cleaned making sure I didn’t overdo it, as I didn’t want the wood getting wet. (And foam cleaner was expensive back then, still is!)

On switching on it worked loud and clear on both wave bands. In fact it is very sensitive across the entire MW and LW band and the large speaker gives a good tonal quality, almost like listening to a larger valve radio. The whole radio was put back together and has worked fine ever since, the picture shows a PP9 battery (the real thing) just for show, I usually use a PP3 rechargeable. I have since seen that one resistor that I thought out of place at the time as it was a smaller 5% 33K metal oxide looking type at the top of the radio, is also in other radios so must be part of the original build.

The Rambler had a missing button, but back then the town also had a Roberts dealer, I expect the radios originated there in the first place, he also had a drawer full of various buttons. I was charged twenty pence just for a replacement on/off button. The Roberts shop has long since gone. The only other thing was to give the dull teak end cheeks a coat of Rentokill Teak oil. Being a capacitor coupled audio stage with silicon transistors it gives excellent sound and will give reliable operation. Both radios still had their handles intact which is a bit of a rarity, just like me

Geof

[Tazman1966]

Not bad for 40p!!! Well done Geofy

[geofy]

Thanks Tas,

They where a bit of a bargain, the pictures where taken yesterday so they have not deteriorated after nearly eighteen years. So not all AF11* transistors go wrong, I have a Perdio Town and Country with the same and that still works fine.

Just a shame the firestation is part time and no longer has a jumble sale as it was a good source of old bits and pieces.

All the best

Geof

[howard]

Hello Geofy,

Gosh two Roberts transistor radios for 42p ! They're both nice radios too, particularly the R200.

Excellent work and I hope you bought lots more 40p bargains which will now be restored.

Howard

[geofy]

Thanks Howard

I was lucky to find these two, I expect they would be in a sorry state by now if I hadn't bought them, I particularly like the R200 as it is so well made and with no parts missing. Though I like using the Rambler as it has very good quality sound. I only wish my local town still had the Roberts dealership there.

I keep looking out for them, the only other one I picked up from a later jumble sale was a small Portadyne but that has a faulty oscillator coil still waiting to be repaired when I can get hold of a suitable part for it.

Geof

[GJR 11L]

Originally Posted by geofy

....not all AF11* transistors go wrong......

No indeed! The transistors of the type that are fitted in many of my sets are either original ones that have never been touched after 40+ years or replacements that have failed after 40 minutes. On sets that I keep in my collection where reliability is not the issue it would be for sets that I sell on, then I sometimes snip those screen leads and again, some have now functioned perfectly well in that state for years, others will last a few more minutes before the whiskers find another path between the remaining connections.

I like to buy sets that are equipped with AF117s though, makes fault-finding very easy in most cases.

[geofy]

Originally Posted by GJR 11L

I like to buy sets that are equipped with AF117s though, makes fault-finding very easy in most cases.

Hi John
Yes this is why a lot of radios are thrown out, when they could be put right again easily. The actual transistors work very well and seldom fail because of semiconductor material faults. If the problem is thin metal spikes growing, this must be due to some sort of electrochemical action in an air gap inside the can, I wondered if a small hole could be drilled, it would only be a mm at most, and something like electrolube injected to insulate the case might get the transistor working again. As AF11* become rarer along with AF12* series this might become more of an option instead of throwing away what might otherwise be a salvageable device.

Geof