Philips 274A No reception

[Old Sparky]

Over the past two or three years I have comprehensively repaired (restored) one of these 1934 'Super inductance TRF receivers, replacing all the waxed paper caps. (concealing modern replacements inside the paxolin tubes which contained the originals), including all those in the metal can!) I've also replaced several out of tolerance resistors, an incorrect rectifier valve and faulty output valve.  Along the way I've checked and double checked my wiring.  Currently I have a working audio amplifier, but absolutely no signals at all  from any point upstream of valve L3.  My suspicions fall on the switched sockets for 'pickup' or 'radio', which, in Radio mode are meant to connect the o/p of coil S14 to the control grid of L3, but does anyone else have any suggestions as to the cause of 'no reception, or a source of supply for the  single pole plugs used for aerial and earth connections?  All DC Voltages are OK, and, as noted above, all faulty components have been replaced.

[Terry]

I came across an old post on UKVRRR from someone saying he'd obtained some from John Birkett here in Lincoln.

I don't know if he does mail order but you can ask - assuming he still has any in stock!

Unfortunately his shop is on a near vertical part of Lincoln, so my arthritic knees would make it very difficult (and probably painful) to get there so I won't be volunteering to pop in on your behalf!

His opening times are somewhat restricted these days but you can find them and his contact details here: https://find-open.co.uk/lincoln/j-birkett-1309682

It would certainly be worth a phone call!

You can see the angle of the roadway here:



Access from one end is by the appropriately named Steep Hill!

[ppppenguin]

What sort of plugs are needed for aerial and earth?

Yes, that hill in Lincoln is steep. I walked up it earlier this year.

[Terry]

I once took the rash decision to walk down from the top, near the cathedral. I doubt it would take most folk more than 5 minutes to walk all the way down to the bottom of the High Street.

I quickly realised my error but it is so steep right at the top that there was no way back. At least I thought I could pop in to Birkett's on the way down but he was closed.

Half an hour later I reached the flat bit near the level crossing!

[Old Sparky]

Jeffrey, they have metal pins about 25mm long and 3.5mm diameter. Modern 4mm diameter 'banana' plugs will fit, but the pin length isn't long enough to switch the internal contacts. I may phone or email Birketts to see if they have any. Hardings shop in Cheltenham is another possibility, otherwise an on-line search may find some suitable connectors.

[Alistair D]

Clix wander plugs used a type of split pin for the actual connection. Perhaps a longer a split pin could be substituted to get the reach you require.

Al

[Old Sparky]

Thanks, Al. I' look into what's available loclly.

[Murphyv310]

Hi.
With no pick up connected the radio will switch from amplifier to radio, so you should be getting radio reception, a simple continuity test should confirm the sockets are switching. These sets are sensitive, even the mains aerial works well albeit if its clean with no SMPS rubbish to induce noise. Take mind they are very sensitive to layout and component types. I've heard of these sets just stopping after restoration for no apparent reason. Mine is 95% original and works perfectly, razor sharp tuning and very sensitive. I even serviced the wet electrolytic capacitors which are totally original.

I'd never consider doing a blanket restoration on these sets TBH as it could be difficult to pin down the problem if the set appears deaf after.

[Old Sparky]

Trevor, as noted in my first post, I have, over a few years, carried out a complete repair, including replacing all the wax caps., and the reservoir & smoothing caps. (This last repair could be easily reversed as I fitted two modern electrolytics underneath the originals, which are still in situ, but disconnected. ) My feeling was that 80+ years old Electrolytics would most likely be leaky and down in capacitance, which, from memory, they were. Although this is the first pre-war Philips and TRF radio I've tackled, over the years I've repaired several 1930s superhets, and not had problems with any of those. As with many head-scratching faults it's probably something simple, such as switched sockets not swiitching. Regarding the layout I was careful to keep it as close to the original as possible, including leaving all the internal wiring as bare tinned Copper, and disturbing as little as possible when fitting replacement components.

[Old Sparky]

I may have found the cause, which is bad contact between the pins of the o/p valve and it's socket. Hopefully I won't have to replace the socket, though getting at the underside of the existing one to tighten the individual sockets won't be easy.