Is this a Pye model MP - or not?

[Skywave]

Update, April 1st, 2012.

After a lot of research within and without the 'Net, I have now answered my own question: "Is this a Pye model MP?". And the answer is no, it isn't: it's a Pye model RS4.
The appearance is very similar (as discussed above), but the real 'give-away' that it was not a model MP was the fact that the MP has 3 wavebands (traditional LW, MW and SW coverage); mine has 4, including two SW bands: 15m. - 50 m. (called 'short') and 60m. to 200m. (called 'med. short').

At present, my camera is not available, but I did find some pictures of the model RS4 on the 'Net: these are below. The condition of mine is broadly comparable to what is seen in these photos - and I also now know for sure that the fitted ECH35 is a 'repair-by-modification': the correct valve is an ECH3.

[attachment=4434][attachment=4435][attachment=4436][attachment=4437]

The style of the cabinet and indeed the chassis is so similar to the MP40 that it does seem very likely that the RS4 was simply the forerunner of the MP model.

Al.

[Skywave]

Hmm: it seems that the mystery is deepening about this set. Apparently, the model RS4 uses a different valve line-up compared to what I have in this set, and that is what I would expect to find in the model MP. But the MP has 3 wavebands & speaker at the top of the cabinet. Mine has 4 wavebands and speaker at the bottom. So I wonder: could it just be that on account of the fact that the RS4 was in production during WW2 - as was the model MP - that because of shortages of parts, Pye built this set as an RS4 but used valves from the model MP?

Incidentally, I did a bit of work on it today. Made the mains input arrangements safe; found a couple of faulty capacitors; a few squirts of switch cleaner; drop of oil on the tuning shaft; hooked it up to a few feet of wire draped around the bench and switched it on (with voltmeters in suitable places ). And it worked fairly well, too. The audio was not distorted, there was plenty of it on fairly strong MW and LW stations. However there is a slight tendency for a little 'tunable' instability: I suspect defective decoupling components, although the EF9 metallised screening looks a bit dodgy. Fortunately, the cct. looks quite basic, so I'm sure that a more in-depth investigation will reveal all. At least there weren't catastrophic component failures found ( I like tempting fate! )

Al.

[Joe]

It's a nice looking thing, Al, and should be really good when it's done.

- Joe

[PA3KIP]

Hmm: it seems that the mystery is deepening about this set. Apparently, the model RS4 uses a different valve line-up compared to what I have in this set, and that is what I would expect to find in the model MP. But the MP has 3 wavebands & speaker at the top of the cabinet. Mine has 4 wavebands and speaker at the bottom. So I wonder: could it just be that on account of the fact that the RS4 was in production during WW2 - as was the model MP - that because of shortages of parts, Pye built this set as an RS4 but used valves from the model MP?

Incidentally, I did a bit of work on it today. Made the mains input arrangements safe; found a couple of faulty capacitors; a few squirts of switch cleaner; drop of oil on the tuning shaft; hooked it up to a few feet of wire draped around the bench and switched it on (with voltmeters in suitable places ). And it worked fairly well, too. The audio was not distorted, there was plenty of it on fairly strong MW and LW stations. However there is a slight tendency for a little 'tunable' instability: I suspect defective decoupling components, although the EF9 metallised screening looks a bit dodgy. Fortunately, the cct. looks quite basic, so I'm sure that a more in-depth investigation will reveal all. At least there weren't catastrophic component failures found ( I like tempting fate! )

Al.

Hi Al,

I've got the same problem,
My radio look exactly like yours, but it uses yet another set of valves: a Mullard TH4B, a MAZDA SP41 and the other 2 are unmarked.
Someone assured me that it is a Pye RS4 (as I suspected) with a modified V2 stage. And indeed all the signs point in that direction.

I haven't tried the radio yet, but started with work on the cabinet.
I gave it a thourough cleaning and together with someone who restores antique I stripped all the old varnish with chemical paint remover and the fineer underneath came out real pretty. Now sanding it with increasingly finer grain and after sanding out all the scratches spraying it with 3 or 4 new coats of varnish.
Replacing the 8uF elco's, replacing some wiring and replacing the speaker with a new 8" one (using the field coil from the old speaker for HT smoothing) I expect everything to work as it should. But you never know with those oldies.

I even found a new powercord with a imitation cotton mantle like the original.


Yours,

Erik

[AlanBeckett]

Pre War Pye had a nasty habit of not putting any identification on the Sets, which is a bit odd as they clearly did have numbers or names. Post War they had little blue plates on the Chassis.
The ERT Sheet lists the IF Amplifier as VP4B, and that was still listed as available for Mainenance in my 1949 Mullard Book.
So, I suspect that MO SP41 is a Foreigner, although whether by Pye or later is anyone's guess.
What's the wiring like round it?

Alan

[pwdrive]

I was following you post on the other forum and would agree with what was said, the SP41 was an RF pentode designed for television RF/IF stages up to 45 mhz, I wouldn't have thought that it was a manufactures modification, that MO valve base is just planted on the top of the chassis, I would revert it back to a B7 base and fit a VP4B in it, that valve is vari mu for AGC control, I don't think the SP41 is.

Lawrence. EDIT: missed Alan's post

[pwdrive]

Just to add, if it was by chance a production run modification by Pye then the MO valve base fixings should be the same as the other valve base fixings which I am assuming are rivets.

Lawrence.

[Skywave]

This is simply an update to this thread I started.

At least there weren't catastrophic component failures found ( I like tempting fate! )
Al.

I shouldn't have said that! Unfortunately, I could not get the local oscillator to operate over one-half of one S.W. band and on another band, the tracking would not 'co-operate'. Despite bringing all my knowledge and persistence to these problems, I eventually admitted defeat. (Some you win; some you lose). A few weeks later, I parted company with it.
Consequently, in this thread, I have nothing more to add about this particular radio.

Strangely enough, now and again, I encounter problems like this (and with similar outcomes) with relatively simple domestic-type receivers. Yet I seem to achieve a far greater success rate with relatively complicated communications-type receivers. Probably a reflection of the quality of the design and build standard of each. To me, sometimes it seems that some receivers were made to be repaired, yet some seem to have been made to be disposed of in the event of strange head-scratching type faults.

Al.

[pwdrive]

Shame about that Al, maybe damp in the coils?

Lawrence.