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Old 1st Nov 2011, 1:57 am   #45
westcliff's Avatar
Join Date: Jan 2011
Location: Essex, UK
Posts: 356
Default Re: KB FB10 "Toaster"

Thanks for the good wishes, Neil. Tonight I couldn't wait, so I put all the valves, etc back and screwed the set into its case, switching it on via the lamp limiter.

The good news is that the lamp stayed very dim. The dial lamp was bright and the set warmed up in around half a minute.

That's all the good news. There was a continuous droning buzz which was loud with the volume turned low. While the set could pick up stations, people's voices sounded like Daleks under water. It sounded good the other week, before the transformer overheated, so I must have done something since then to make it sound bad. When crackling started, in addition to the other unwelcome sounds, the set was switched off. It sounded the same on MW and LW.

It was on for around three minutes and there was no noticeable heat from the transformer.

One thing I've not done is to touch the alignment. Okay, one of the little exposed coils attached to the tuning capacitor had fallen off, so I soldered it back on, but the set sounded fine after that.

I mentioned yesterday that the leads on the replacement transformer were shorter than on the original one. One problem I had was the lead to V4, pin 7. This was originally routed round the edge of the chassis. It is now routed straight across several components. Could something be picking up AC by inductance? Nearby components are C12, C15, C18, V3 and of course V4 (Trader sheet 969 references). Please excuse me if this is a daft question.

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