Philips 2514

[boiss]

I have had a Philips 2514 for about 20 years, in good order apart from the fact that it had no valves or base plate. Tha base plate is not a problem to make and I had 10 Philips model/serial no plates made up that just need the model and serial nos punched on them.
In these 20 years I have only found 1 valve for it which I bought. I have never seen a 506K valve advertised or offered for sale at Amateur radio/electronic fairs. The other 2 valves, E415 and E442 that I have seen have been offered at horrendous prices at the level of one weeks pension each and their performance was not guaranteed. So rather than have this, What my wife calls "Piece of junk" hanging around, I thought it would be better to "Sand it" Ie, Diodes, Fets and Transistors like the "Fetrons" of the 70s. Certainly modern Fets offer far more versatility than those of the 70s and 80s. Gasps of horror here! But it would be without modifying the radio itself. I would need some valve bases or failing that make some plug in bases to hold the components. The main problem appears to be to find some sort of plugin pins to replace the original valve pins. If and whenever valves are found they could be kept to restore to original state.
Your thoughts please?
Cheers
M

[Herald1360]

Would it not be easier to do something similar but with more readily available period valves?

Is there anything particularly "special" about the original types other than their "only found behind incontinent rocking horses" status?

[PJL]

There was another recent thread with the same problem https://www.vintage-radio.net/forum/...d.php?t=197876

[Silicon]

Langrex sell '4 pin replacement British valve bases' for £10 each.

I assume you could plug these into the 4 pin valve holders in your radio.

Broken or faulty valves with B4 type valve bases could also provide the necessary connections.

[boiss]

Originally Posted by Herald1360

Would it not be easier to do something similar but with more readily available period valves?

Is there anything particularly "special" about the original types other than their "only found behind incontinent rocking horses" status?

The valves are from the mid 20s, most valves from that period were meant to run on DC and the F.W. rectifier is very short. More than anything I don't want to make any changes to the radio. The plug in Fets would make that possible. I always carry in my wallet a list of the valve equivalents just in case! I have often (every week) gone to flea markets etc and found a rare phone or valve on the last stall visited!!

[boiss]

Thanks I will check Langrex out!

[boiss]

Being tight (Small pension) I have found some 3mm sprung pins so I will make my own bases. More work but time is not a problem.

[boiss]

Fitted a new mains lead, and took the can apart with the 6 capacitors inside. I found some pics of the restoration of one of these radios but the resistors in the side panel are R8, R9 and R2 (not R4). Resistors are wire wound and the values are about right so apart from some contact cleaner on the bias pot nothing was changed. The original cable wire colours have Earth/Chassis on Black, Green on the Casing switch and Red going to the transformer overheating "Fuse". I swapped them so with modern cable Brown goes to the casing switch and Blue goes to the overheating fuse. So removal of the case disconnects the live side supply to the transformer. Getting the Caps out of the can is fun and takes a bit of time, They are almost all 1uF and modern 450V ones will be used to replace them. Original cardboard casing inside and outside the can will be retained. Wiring is surprisingly good after 85 years. Lots of bitumen insulation around critical points.

[boiss]

I should have said wiring good after 95 years.
Without valves applied power to the radio, everything Ok. Voltages for heaters and transformer O/P volts OK. Plugged in semi-conductor rectifier assembly, 100R across htr, 2 x 1N4007 each with a 1.5k series R. Voltages seemed OK then Neg bias voltage disappeared and smoke came out of the panel with the volume/bias control.

[boiss]

Had to leave off at that point, got called away.
I confirmed the smoke!!
Removed the mains transformer again and removed the internal side panel. Reconnected the mains transformer with long leads and switched on, it was the 240R pot getting hot. A few measurements showed something going to deck. The two resistors potted in bitumen appeared to be the cause, S/C on a wire, They should have been 100K, one was O/C and the other was 260K. Replaced with 2 new 1W resistors in shrink sleeving. Powered up and no smoke, neg voltage about -25V and from the pot +0.2V to -5.3V. The resistors are not as in the cct diagram. The pot is 240R and the resistance to deck is 20R instead of 60R.
Remounted the panel and powered up all Ok. Remounted the transformer and then started resoldering the original wiring one by one, powering up and checking after the replacement of each wire. Finally all working Ok. Reduced the 24K load on the HT supply to 12K. HT a bit low at 175V maybe due to the 1.5k series resistors in the rectifiers. Also the Neg bias supply detracts from the HT.
All the valve bases have been made with side contacts etc as per the originals. I have not done anything with the Mosfets yet as I am waiting for the 15V zeners to arrive, to limit the gate voltage in order to not risk damaging them. I hope the O/P bottle ( Only valve I have) is OK otherwise I will need to add a power transistor due to the dissipation of the valve.
Pics Later.
Mike

[boiss]

Some pics of the semi-conductor Valve replacement holders awaiting Mosfets and a few other components

[boiss]

Some more pics.

[boiss]

And the last for the moment.

[Nuvistor]

[stevehertz]

There's a 2514 for sale on eBay complete with valves. I realise that you don't really want another set as such, but if you can get it at the right price, use it to make up a 'perfect' set, then sell whatever is left to make some of your money back. Just a thought.

[PJL]

The 2514 comes wound for a specific mains voltage marked on the model label on the underside, mine is 253V which is perfect for the UK.

[stevehertz]

Originally Posted by PJL

The 2514 comes wound for a specific mains voltage marked on the model label on the underside, mine is 253V which is perfect for the UK.

Sorry, not quite seeing the point you're making - is this with reference to post 15? The one for sale (as far as I can see) doesn't state a mains voltage although I'd wager it's UK voltage, but it wouldn't stop you cherry picking the valves and other parts to make up a good set.

[PJL]

In part, but as the base plate is missing on the OP's 2514, he will not know the intended mains voltage...

[stevehertz]

Originally Posted by PJL

In part, but as the base plate is missing on the OP's 2514, he will not know the intended mains voltage...

That's not what he's saying in post 16.

[boiss]

The voltage on mine is stamped on the Chassis 225V. OK here, it is generally 230V. Heater voltages are about right but they only have about 1/3 of the normal load (3 x 100 ohms resistors) rect heater is also 100 ohms. Set is aweful regarding ground/earth/chassis. Even HT on both sides of tuning cap (keep the Knob on!). Circuit tracing is diabolical especially when sorting the Caps in the cans.
A few years ago I copied the ID plate from another 2514 which is on the bottom panel which I didn't have. I got 10 made when I was in Korea, they just need to be hand stamped with Model No, S.No, AC freq, and Voltage. S.No, is stamped on the chassis inside.
I'm too hard up to think about buying another set for parts unless I get an inheritance from somewhere! I've also seen others in the EU having found duff valves O/C transformers etc.
Mike