1929 Gecophone BC3047

[amanitavirosa]

Hi I recently purchased a 1929 Gecophone BC3047 from eBay. It's missing it's valves, speaker and original case. It's unlikely that I'll restore it to full working condition, but if anyone can help me find a circuit diagram or valve list I would be very grateful. It uses 4, 4 pin valves one of which I believe had a screw on top cap and is mounted horizontally. A picture of the full set can be seen on the radio museum.org website. Any help is greatly appreciated.

[Ed_Dinning]

Hi, a set of this type will almost certainly use a screened grid valve (tetrode), the one with a top cap, which often pokes through a metal screen. This is the first valve from the aerial.
The remaining 3 valves will all be triodes; possibly in the sequence of detector, 1st AF and then output.
The triodes will all be slightly different types because of their functions, but they should be available at not too great an expense.
A Google may turn up the circuit. The audio end of the set may be very similar to the Gecophone "Music Magnet of about a year later, a very popular kit set that used 2 SG valves.
There are many different valves that can be used in the set (equivalent types) so you should have no difficulty getting it working; the passive parts used are easy to repair/ replace and you will get a nice set.
You will usually need to sort out the many battery supply leads. They will be for HT and GB voltages as well as the filament supply.

DO NOT operate the set without GB connected, or change GB tappings while the set is powered or you will destroy your valves.

Keep us posted about your progress.

Ed

[amanitavirosa]

Thank you for that information I'll try searching for the circuit

[greenstar]

Cases do turn up.

[Ed_Dinning]

Hi There were also valve booklets produced by the major manufacturers that listed their preferred valves for a whole range of sets. Unfortunately mine only go back to 1934 and you set is not listed.

Ed