PYE Portable radio

[Manx Nick]

Hello all,

I was given this little portable valve radio today, are they hard to work on? Mine even has the original batteries! It's in a very tatty state though. Any thoughts on how to power it? Bank of pp3 9v?

[Sideband]

You can take the batteries apart and restuff them with modern batteries. 10xPP3 for the 90V and a couple of C cells in parallel for the 1.5V. I've done that with my Roberts P4D and alkalines last for ages.

Be very careful with these battery valves if you haven't worked with them before. The filaments are very delicate and won't take much overvolts. Generally they are rated at 1.4 volts and will work down to about 1.2. Don't accidentally mix up the LT with the HT or allow them to short or a new set of valves will be required.....no second chances with these!

[Manx Nick]

Thanks very much for the info, please forgive the ignorance but how would you combine the batteries?

['LIVEWIRE?']

For the HT use 10 x PP3 9v. Batteries wired in series-i.e. connect the positive terminal of one to the negative of the next one. etc., etc., I've not attempted to fit 10 PP3s into the case of one of those batteries so I don't know how best to arrange them physically. No doubt another member will! For the LT, connect two 'C' cells in Parallel.

[G8UWM-MildMartin]

One thing to watch with the Pye P114BQ is failure of the primary of the output transformer.
It is attached to the loudspeaker (which is connected to its secondary.) It should be 570 ohms, according to the service data, and, if you have a multimeter, probably worth checking before buying batteries and, if you don't, it may be worth buying a cheap one for less than the cost of a set of batteries anyway.

Second thoughts, cheaper to just rub a 9-volt battery across it and check you get some noises!

Once it's working on batteries, Paul Stennings's battery eliminator https://www.vintage-radio.com/projec...y-set-psu.html is good and relatively quite cheap to make if you want a mains power supply.

[Ed_Dinning]

Hi Nick, a few resistance reading on the valve heater pins and the output transformer may be called for first, as well as positively identifying the HT and LT leads

They are a nice little set and work well.


Ed

[Mike. Watterson]

1.5V max for any speaker or even 4K phones.
You can plug five PP3s into each other and then they will fit side by side in a replica box. You can make a socket out of cut up coffee tin (folk that don't have a dead pack). So only 2 x PP3 connectors cut in half needed.
1 x Alkaline D cell should fit in 1.5V box.

Grid and screen grid paper dielectric caps need replaced. These sets work well. I've done two. Often the tuning knob is broken.

The -HT must connect to chassis / OV / LT- minus via 470 to 1500 Ohms on almost all 1.5V LT battery valve sets. The grid resistor of O/P valve then goes to -HT to get the -ve bias. The sets with 7.5V or higher LT usually have a mains option and then the output valve is at the +ve end of series chain (the DAF91/DAF96 will be at 0V and the DK91/DK96 next, with the DF91/DF96 between it and the DL94/DL96 or whatever in series filament mode instead of parallel filaments, so voltage on mains = 5 x 1.35 (MAX) or about 6.5 +/- 0.3V, not actually 7.5V.

A small mains transformer out of cheapest Argos clock radio will do audio transformer as the bias current is low. I've lost count of how many battery sets have a dead primary on speaker transformer due to the grid capacitor of output valve. Often it does in one half the filament of a DL96.
DL94s can output more, so no surprise many transformers on them "burnt out". Very fine wire.
Also common on pre-1932 sets due to grid battery going flat after a year or two. With them it's often the intervalve transformer too. They are often 1:5 or 1:2, so again a suitable small mains transformer can be used.

[G8UWM-MildMartin]

The presence of HT & LT batteries makes it easy to identify the leads and they'll yield suitable sockets for connection/build of alternatives.
9V "flashed" across the primary of the output transformer should be OK as a quick test.

[Stylo N M]

Hi.

Geat little set to work on I've restored three, as others have already said the wax paper capacitors must be replaced first. There are several of these along the very front edge of the board, at a value of 0.01uF 10,000pF a 400 volt replacement will suffice, I used the yellow polypropelene ones as replacements. There is also one of these that hides at the back in front of the wave change switch, and also another one that is very well hidden, in the area at the end of the board, near all the leads from the pop up on and off switch. This capacitor is a bit difficult to get at, it's wax paper again and the value is 0.002uF 2,000pF the modern replacement for this is 2,200pF or 2n2 at 400 volts or higher, it's a tone correction capacitor, and sits accross the primary winding of the sound output transformer.

OK- now I know we all do this differently, but what i did was, I cut the protective sheathing off the top of all the PP3 snap on connectors, and removed the red and black wires. I then place them all out into a certain pattern ensuring that + was always in line with - negertive, corresponding with the next battery in the line, and soldered thinish wire over the remaining rivits of all the PP3 connectors always going + to - and that way I was able to pack the × 10 PP3 cells tighter together.

It's amazing how much it reduces the height of the PP3 9 volt battery by just stripping away the sheathing off the top of all the connectors.

Now a trip to the shops, I went and looked at some various after shave boxes, to see which was the smallest sized that I could fit the 90 volt pack into, it was tight but I found some. Then off to the craft shop to get some eveready blue card I covered the boxes with the blue card, measuring each piece out pefectly, used the thinest red and black single pin plug from Maplins, I mounted those on the side of the battery towards the back end, and some velcrose glued to the ends so the flap can be opened and closed when changing the pack.

I did the same for the LT 1.5 volt I used ×3 AA cells in parallel, and used a nice flat Aspirin box covered with the blue card in the same way, and used the larger red and black single pin plugs (the vintage ones) and sockets on the top of the box towards one end, (the end farthest inside the cabinet) I call it my AD35 mini.

Yes it is all a tight squeeze and a bit of a bind soldering the wires to the sockets inside the boxes, espeacially the tiny ones on the 90 volt HT pack, as you do have to remove the sockets each time you restuff, but it's all do-able if you're up to it, and it's fun putting your own markings on your home made battery packs! and you can restuff for ever.

Paul

[Stylo N M]

I don't know if the picture has uploaded, beacuse it's my first attempt at trying to do it, but here are my examples of the finished batteries. Mods please delete this post if the picture has not shown or uploaded, it obviousley means it won't work from this moblie or i can't do it for some reason.