1953 Marconi portable radio

[Escondido]

We have a 1953 portable Marconi radio. Where can I get a battery or a converter? Would like to hear it working. Many thanks

[Graham G3ZVT]

Can we have the model number?
Better still, post a picture or two.

[Phil G4SPZ]

The simplest and cheapest approach is to use ten cheap 'pound-shop' zinc carbon 9 volt PP3 batteries in series, giving 90 volts for the HT (high tension) supply, and a single C- or D-cell giving 1.5 volts for the LT or Low Tension supply. The PP3s can be plugged together (+ to -) and the single cell can be fitted into a battery holder.

You will need some competence in soldering, and also it is vitally important to identify the correct polarity and identity of the four wires or else lasting and expensive damage can be done.

There are suppliers who make ready-made replica battery packs, which you may find easier and will look a lot more authentic. https://www.classicradioshop.info/va...dio-batteries/ is one such supplier (I have no connection with them) but they look good. Again, these are NOT simple plug-and-play items and you will need to identify the wires and connect them up properly.

Personally I would avoid power packs or battery eliminators. For one thing they tie your portable set to the mains, and unless very well designed they can inject noise which mars reception. Unless you want to use your classic 1953 radio all day long, I think batteries are the way to go.

Finally, the radio itself may be faulty. Try it and see, but if you want reliability it would be wise to get it checked over by someone who offers such a service - see 'services offered' on this Forum.

[marconi_pete]

Yes Pictures please. Based on the assumption that this is set is likely to have originally run on two separate batteries (One for HT and one for LT), you have two options. One is to make up the required HT voltage with 9 volt batteries connected in series and use a 1.5 volt C or D cell for the LT. The other and my preferred method is to use an old Nixie clock inverter circuit/psu. With this method, you can achieve the required HT voltage with just a single 9 volt battery and the inverter circuit itself is roughly the size of a matchbox, so would easily fit inside the set with no modifications. The circuit has an adjustable voltage regulator, so can be set to the correct HT requirement for your set. For the LT again I would just use a single C or D cell. This method also keeps the set portable and means you don't have to mess around with mains. In my own experience, I've not needed to add any screening and theres no noticeable noise when the set is in operation. Typically Marconi battery portables of that period required 90V DC for HT and 1.5V DC for the LT supply, but not all Marconi battery sets are the same, so please don't automatically assume this. If you opt for the Nixie inverter circuit option, the circuit boards are readily available on the bay and other well known auction sites and can be obtained for around £10 with postage.

Thanks,
Peter

[Phil G4SPZ]

The Nixie PSU idea is interesting, but how do you suggest the OP switches the HT supply? Many battery portables switch only the LT. Even if the HT is switched as well, this would switch the output from the inverter only, but leave the inverter powered-up and draining the supply battery.

[marconi_pete]

Apologies as I should have mentioned this in my pervious post. To stop the inverter from draining the battery under no load conditions I install a second pressure switch next to the original on sets with the clamshell/lunchbox design, that disconnects the live from the battery when the sets lid is closed and completes the circuit to the inverter when the sets lid is open.

Thanks,
Peter

[Phil G4SPZ]

Escondido, you've been given plenty of advice. It would be nice if you were to let us know what you decided to do and how you got on.