Does anyone have a circuit for the subject radio?

May also be an Astor circuit.

Pye R16-04A could be a chassis type & not a model number. For instance, a Pye model MR2 chassis type is a R16-1A. This is probably why it is not showing up on any of the circuit indexes. Does this model use a printed circuit board? Is it valve or transistor? Is it mains or battery powered?

A valve (or transistor) line up and some photos will be most helpful in identifying the model. Brad, the administrator, will upload them for you.

Monochrome625.

There are no markings or identification on the cabinet other that the Pye emblem. It is a valve type on a printed circuit and is mains powered. The valve line up is V1-6BE6, V2-6BA6, V3-6AV6, V4-6AQ5 and V5-6V6 I will get a photo shortly. However, if you have access to the March 2014 edition of Silicon Chip page 20 under the Crosley CR3022A Ranchero retro radio in the article Retro Roundup by Kevin Poulter to show a simular radio from the 1950s. I could reverse engineer the circuit, but there are a couple of strange wiring details (such as the positive speaker terminal is grounded-perhaps heavy handed soldering in an attempt to repair the radio). Also the circuit would provide optimum IF frequency details (not always 455kHz). Many thanks for your reply.

Both the Pye MR-1 & MR-2 (R16-1A) use the same valve line-up you have mentioned. Both also use a printed circuit board. The MR-1 has an input for a phono pick-up. IF frequency for both is 455kHz.

Pye MR-1 Circuit Diagram.

Many thanks Monochrome625, that looks very much like the circuit that I need. The top view of the chassis (fig 3) shows the front panel (in top view) to be identical. Also I did make a typo for V5 as it is a 6V4.

Thanks again,

Mike

Here is an advertisement for a Pye Ranchero from the Canberra Times, December 1959.

The one in Kevin Poulter's article has a different style Pye badge to the one in the ad. Now I'm wondering what style cabinet the MR-2 has. Just to confirm, does your Pye have the phono pick-up input?

There is no phono pick up that I can see. The badge is the gold trim with a white TV screen image and the Pye logo in the middle. The same as Pye TV sets had at that time (my uncle had one). It must be later than the Pye Technicos that had the round Pye label with a stylised single wing for the Technico part.

Regards,

Mike

Thanks for the photo Monochrome625. The differences are; the round (red) Pye logo, as I said earlier mine has the later white and gold TV screen type logo and the dial has NSW (vertical) on both sides rather than the 2 on the left side. There may be a slight difference in the knobs but that is too hard to tell from the photo.

Thanks again,

Mike

I just picked up one of these (see https://www.radiomuseum.org/r/pye_au_r16_04a.html for photos of a typical unit of the same colour). The oscillator is not working, a new 6BE6 made no difference, and the PCB makes it difficult to follow the circuit.

It looks very cheaply made, a knob is missing, the ferrite is cracked in half and someone has been there before me. The "gold" plating is peeling off too. Unable to identify anything on the PCB due to a black coating of nicotine over everything. Probably just rubbish but I'd still like to find out why it doesn't work.

After thinking about it, I decided to do a blanket resolder job around the 6BE6, as PCBs and dry joints go hand in hand. This fixed the radio's reception problem.

But, all this did is reveal more issues.

- Speaker is shot, needs replacing.
- Ferrite cracked in half, needs replacing
- With external antenna it is very sensitive, but with just the ferrite it is hopeless.
- 6AQ5 output valve gets excessively hot
- Dial cord is threaded wrongly, dial pointer gets forced off the cord
- AGC not working, strong stations cause gross distortion.

and so on...

Hey, it's an old radio that sounds like it's had a hard life!

6AQ5s do get hot normally but check the back bias resistor R8 - 150 ohms. Low resistance Morganite and Ducon 1W carbon composition resistors go lower resistance with age, Replacing it, I'd go up a step to 180 or 220 ohms to bias the valve more so it draws less current and lasts longer.

Check R10 too, same story.

If C11 is a paper cap, replace it!!

Re AGC, look for a Ducon Redcap ceramic on the AGC line - C6. It'll be leaky.

Oh, I did some work on this while the forum was down.

The broken ferrite rod was replaced with a spare. The alignment was done by sliding the winding at the low end of the band, then adjusting the trimmer near the high end. It now picks up lots of stations without needing the external antenna.

The AGC cap was found and replaced. One problem is the part numbers printed on the board did not correspond to the numbers on the schematic.

Then I decided to adjust the back-bias resistor to get the grid bias closer to 12.5 volts. I can't remember exactly what I ended up with, but it was around 500 ohms. This was bypassed with a 16 volt 100 μF electro. This keeps both the 6AQ5 and the power transformer cool for much longer although eventually they get as hot as before.

The speaker was replaced.

I had a look at the dial cord. Unfortunately it will need to be totally redone, I really don't know what the previous repairer was thinking, and the picture in the schematic isn't the same layout as the actual radio.

And, the sound is distorted all the time. There isn't really much else to check.

Regarding continuous distortion:

Is the bypass electro value a bit too high? Could you substitute a 47mF and see if the distortion is reduced.

100 mF seems a bit high, may be giving you too much bass gain? I'm not sure, is 100mF an original spec??

Mike, Put the back bias resistor back to original.
Replace R9 680K, C11 and C14.
Replace 6AQ5 because if it has been operating for any length of time with incorrect bias, it will be stuffed.
JJ