I have one of these to get going for a museum.

It's been slightly got-at and I'd like to restore it to what it should be.

Kevin's site has the 79 in the index but it's actually a Ferris model 79 car radio.

The similar model 80 is there, it's a 5 valve circuit, the 79 has six.

Anyone happen to have a copy?

I just found this. Hopefully it is what you need and can be enlarged.

https://www.radiomuseum.org/images/schematic-medium/breville_sydney/79_1934140.png

I have a Breville console radio from around this time. I am not sure of the model number. If yours is a console I'll check mine next time I am up north, where it is stored.

Thanks Brad!

Very much appreciated.

Some of the values have been lost in the reduction but in conjunction with the good Model 80 schematic I should be OK.

I haven't pulled the chassis yet, didn't know it was dual wave.

And the B217 looks like a much earlier bottle but the data shows it was released in 1933.

At least it has the 1C6 pentagrid and AGC. And a Class B output to save the B battery!

I am willing to bet that the circuit diagram is from a volume of the AORSM. I'll search through the ones I have tomorrow and see if I can find it. Scanning that shouldn't be a problem.

The Breville 79 schematic from Radiomuseum comes from the 1938 Radio Trade Annual. It is not in the AORSM.

According to Radiomuseum the 79 chassis is used in four cabinet styles: York, Devon, New Beale & Beale Edward.

I've sent a copy to Kevin Chant and hopefully he can replace the Ferris 79 schematic.

https://www.kevinchant.com/uploads/7/1/0/8/7108231/breville_79.pdf

Thanks mate, that's much better!
Bandswitch actions around the 1C6 are explained too.

Anyone have any pinch drive knob spindles in the junkbox?

This one does not drive despite freeing up the gang. There is no lash adjustment to compensate for wear and no spring loading on the pinch.

A horrible design! There is less than 0.5mm penetration of the disk into the pinch.

The pinch gripper thingy is only about 8mm diameter, a larger one should work better.

I do hate those drives; however, is there a possibility it had a spring? One never knows what has happened to it over the years. There is also the risk that it has actually over time, worn down the edge of the driven segment.

There are a few variations on the theme and as there are no springs, it may have been a friction drive with a rubber tyre?

Maybe you can conjure a friction drive out of two shim washers if you can find them with the appropriate dimensions. Therein would be the problem.

They would need to be springy eg steel or phosphor bronze, and capable of being given a slight dish shape to fit the driven element.

I can imagine the thing having come across a few, That's why I wondered about a tyre like a sewing machine bobbin winder has. You an cut groves into them.

I included photos of a friction drive shaft assembly here:

https://vintage-radio.com.au/default.asp?f=12&th=120

See figures 19 & 20.

Yes the dial mech could have come out of the same factory, although the Breville one is simpler.

The disc edge is worn. I tried doing a solder pot tinning followed by hot air (HASL technique used in PCB production) without much success.

No way to separate the sections, as some stage someone a long time ago has pinned and brazed the bits together and turned it down in a lathe.

What worked finally was two layers of heatshrink over the drive zone on the shaft. Now works without slipping with a nice feel to it.

The B217 2nd audio driver was u/s. Couldn't locate its sub, a 30, for less than stupid money. So I changed the socket and fitted a 1B3 with 6.8 ohms in series with the filament.

This worked very well, albeit with far too much audio gain, so I added some negative feedback with a 470k from a 19 output plate to 1st audio plate. That got rid of the audio peak at about 2 kHz. and it sounded quite good.

And then half the output transformer primary went O/C! THD rose to 50%!

After trying a PA line transformer (a bad match) I have a very expensive Hammond 125A purpose designed transformer on its way.

And then half the output transformer primary went O/C!

In my experience, serial failures do come in threes. Hopefully yours stops there.

I had thought that the disc in my case was heavy tinplated steel gone dark with age. But when cleaned up it looked like some sort of phosphated or chromated finish. This would not take kindly to solder.