Treasure in the loft – vintage radio preserved in lovely dry place? Watch out as switch-on-shock could kill it – in a flash!

By Dorian Stonehouse

MOST of us have done it:  stored a vintage radio (or anything electrical or electronic for that matter) long-term in the attic (loft).

In a well insulated attic, seasonal temperatures can cause radio components to contract, expand and/or dry out. 

This lovely Swan 500 transmitter/receiver had been stored in my attic (loft) for well over 30 years

After such ordeal, should you decide to bring your vintage set downstairs and switch it on “to see if it works,” you can expect either complete silence from the loudspeaker; or one big bang, accompanied by a plume of smoke!

No need for a complete respray, as a drop of ‘3 in 1’ bicycle oil and a cleaning cloth will restore the cabinet to its former glory in next to no time!

Once out of storage, radios in general should be placed in a well-heated room for a few weeks, thus allowing sufficient time for components inside the set to acclimatise to the more constant room temperature downstairs.

Full mains power up should initially be avoided

There are a couple of really good methods of improving the odds for a successful (post storage) power up.

Here is one such method that involves placing a lamp in series with the set, so that the mains voltage is shared between the both:

A ridiculously simple but effective idea which takes vintage radios out of hibernation safely

The left side plug in the picture is connected to the mains supply; and the live wire emerging from it is connected in series with the light bulb, and then to the live pin of the second plug (right side).

The neutral wire emerging from the left side plug goes straight to the neutral terminal on the right side plug.

Bringing my old Swan 500 transceiver out of hibernation – gradually

The radio is plugged in to the right side trailing socket and switched on.  The total voltage will be shared between the bulb and radio, and the radio will be silent.

The bulb will also absorb much of the surge on switch on.

Caution: the floating plug attached to the right side trailing socket will now have live pins exposed. 

Simply pushing the plug into its socket will solve the issue by shielding the pins.

The radio should be kept running on the bulb for a few hours, thereby warming the radio up gradually.

Further rummaging reveals another old gem:

the Swan 230 xc power supply

My Swan 500 transceiver, complete with the power-supply and loudspeaker unit

The curse of switch contacts and sockets

Tarnished contacts are perhaps the most obvious, yet the most overlooked fault that can befall a radio which has been in storage.

All pins and sockets should be cleaned with glass- fibre pen or similar tool, saturated with a quality electrical contact cleaning solvent  

Where there is no chance of a contact cleaner causing frequency degradation, a bicycle oil (3 in 1) can be dripped onto the plug pins, before repeatedly pushing and pulling the plug into the socket to remove tarnish.

Taking the lid off the Swan 500 transceiver

Despite being in storage for many years, the Swan 500 was in great condition and was now ready to be powered up directly from the mains electricity supply.

The tubes are a glowing like little village lights…

heralding the Swan 500, springing back to life!

A nice audio hiss is a good sign that the receiver stages are working properly.

On this Swan 500, Morse code could be heard just above 14 megahertz, with only a short wire antenna attached.

The control pots and selector switch contacts will most likely need to be cleaned, as was the case with my Swan, so off came the bottom cover…

If you intend to keep the radio in authentic 60’s condition, think twice before replacing original components with modern ones 

The control pots carbon tracks are easily cleaned in situ with a drop or two of bicycle oil (lasts longer), or a squirt or two of electronic contact cleaner.

Also, in need of a good clean will be the band changer (waver) switch, located inside the VFO can on the top side of the Swan 500

Never tamper with the vanes of the variable capacitors/trimmers inside the VFO housing (or anywhere else)!

Checking the pair of tubes 6HF5 showed that emission was a tad down on both, but they were still fighting fit!

A pair of 6HF5  tubes

Watch out for loose top caps  

 

Apart from a slightly right-of-centre carrier, my Swan 500 showed a respectable power of about 400 watts (depending on the mic gain control position), while connected to a “KW 107” “Supermatch” internal dummy-load.

It wasn’t long before I was enjoying a QSO with a station on the other side of the World, thanks to this iconic piece of USA craftsmanship.

Good quality audio modulation was assured by using a “shure” microphone, presented to me by GURU Garland

Here are some more pictures of my Swan 500 transceiver for you to enjoy:

Dear visitors

I hope you have enjoyed this feature on my Swan 500 transceiver, and should you have any questions relating to this iconic radio, I would be very pleased to try and answer you.

In the meantime,  please may I ask you to let other people know about electrosparkles.com by cutting and pasting the url of the page in question to your social media pages for circulating.

Also, if you have any high quality scientific photographs available and you are prepared to share them with the World,  please would you be so kind as to send them to me.

All the very best

Dorian.

 

 

 

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