Your circuit looks pretty close, no obvious errors on a quick peer review!

There should be a capacitor across the secondary of T2 - upper winding on the circuit.

It has a very important role tuning the transformer and prevents high voltage breakdown of the transformer and the vibrator.

It's usually about .01μF or a little less, but it MUST be a high current type (these days intended for SMPS service) and is typically rated at 2kV. After the vibrator it is the most common part to fail in that circuit. And when it does fail it often takes other stuff with it!

I used to fix car radios as a kid in the 50's and that cap was always bad.

You set looks to be in about the same state as the Airzone Radiostar I restored about 20 years back. I did a complete bare-chassis stripdown on that one.

Your cabinet might be a bit far gone for a cut-and-polish job. I've used automotive clear-coat in such cases, generally comes up like new.

I see a few questionable things there, but then again my specialty is AC sets rather than battery ones. Still, I'll list what doesn't seem right to me.

R5 is shown connected between HT and the filament of the 1C6. Probably a bad idea.

The G2 pin of the RF amp and 1C6 doesn't have a voltage supply. I'd suggest that R5 should do this job.

The arrangement of the 1B5/25S and volume control looks quite odd. The anode has no voltage supply. Check carefully around pins 2 and 3.

I am not at all sure of the purpose of the "bottom end choke" and C5 - at least in the way they are drawn now.

Thanks Robbbert and Ian, much appreciated. I will let you know what I find when I recheck the radio in a day or two.
cheers
Jon

Thanking you 2 for your input, it has helped greatly.

I have gone back over the radio

QUOTE:
There should be a capacitor across the secondary of T2 - upper winding on the circuit.

It has a very important role tuning the transformer and prevents high voltage breakdown of the transformer and the vibrator.

You are right, I missed that, inside the can that covers the transformer there
are 2 capacitors, one from each of the secondaries to earth, they are pretty
bad (splitting apart and gooey)

QUOTE: R5 is shown connected between HT and the filament of the 1C6. Probably a bad idea.

The G2 pin of the RF amp and 1C6 doesn't have a voltage supply. I'd suggest that R5 should do this job.

Yep you are right, I had R5 wrong, it does exactly what you surmised, it
doesn't connect to the cathode, it runs to the G2 pin of the 1C4 and pin 5
(G3,G5) of the 1C6

QUOTE:
I am not at all sure of the purpose of the "bottom end choke" and C5 - at least in the way they are drawn now.

I had that wrong as well, the choke comes from the battery and is then
connected to the transformer primary centre tap (and that line is connected to
earth via C5 after the choke).

QUOTE:
The arrangement of the 1B5/25S and volume control looks quite odd. The anode has no voltage supply. Check carefully around pins 2 and 3.

I checked and re-checked the connections on
the 1B5 multiple times and kept coming up with the same answer (over 2 days)...

I started in desperation to think perhaps the valve wasn't using the triode
part at all.

Then after removing some of the components to make really sure there wasn't
something hiding there I hadn't seen, I saw the marking on the valve socket and
I realised I had misidentified pin1

All the connections were 1 pin out! What a goose I am! :-x

I have redrawn the circuit fixing the bits above up.

https://www.kellyavia.com/projects/radio/apollo/images/pdf/197.pdf

I really appreciate the input on this.

I’ve come in late to this discussion.

I think this is an Eclipse chassis (also mentioned in a previous post) going by their in-house “Saxon” paper capacitors I can see.

There is an Eclipse model 552/12 listed in the 1937 Radio Trade Annual with same valve lineup you guys have agreed upon. Despite this model being a console, l believe the 552 series chassis was used in a multitude of Eclipse/Croyden models, including rebranded generic types (Apollo?).

Hope this clue helps.

Had a look at the new diagram and things look much better. The only issue now is around the 1C6 frequency changer tube.

The tube has no AGC applied, but this might be normal.

Pin 6 is shown connected to the volume control / grid of the 1B5, when in fact it should be earthed. Otherwise the filament won't light up.

I'd suggest taking a very close look around the 1C6 on all its inputs. It just doesn't look right at the moment.

Yes, V2 pin 6 is a worry.

To run the 2V filaments on 6V in a 5 valve chassis, bearing in mind the 1D4 draws 2x the filament current of the other valves, it was normal practice to connect them in series-parallel. Like this:

+6V
1D4
1C6 // 1B5
1C4 // 1C4
Ground

Or sometimes

+6V
1D4
1C4 // 1C4
1C6 // 1B5
Ground

Either arrangement neatly provided bias for the 1D4.

So V2 pin 6 should either go to ground or to Pin 1 of V4.

In the first case, that would be the reason for the 36 ohm resistor.
In the 2nd case, the resistor would not be needed.

Update - I just checked the filament currents.

The 1B5 has a 60mA filament. (I didn't know that!)
The 1C4 and 1C6 have a more common 120mA filament.
The 1D4 has a 240mA filament.

So that explains the 36 ohm resistor, connected across the 1C6 and 1B5 filaments, to make up the difference.

Like this:
+6V
1D4
1C6 // 1B5 // 36 ohm resistor
1C4 // 1C4
Ground

Normally, that extra resistor (it takes the place of a valve filament) was only used if there was no RF stage. In this case it was 16,6 ohms.

Oh, on your circuit, there is a note about a suspected two-part electro,, with 3 pins.
That is a twist-lug type, normally fitted above the chassis. The two outer lugs connect to the can, and are normally grounded.

QUOTE:
Pin 6 is shown connected to the volume control / grid of the 1B5, when in fact
it should be earthed. Otherwise the filament won't light up.

I'd suggest taking a very close look around the 1C6 on all its inputs. It just
doesn't look right at the moment.

QUOTE:
So V2 pin 6 should either go to ground or to Pin 1 of V4.

In the first case, that would be the reason for the 36 ohm resistor.

Yep, as you both suspected, I had connected that wrongly on the schematic.

on checking, V2 pin 6 goes to V4 pin 1 as Ian suggested.

I have redrawn the diagram.
https://www.kellyavia.com/projects/radio/apollo/images/pdf/197.pdf

QUOTE:

There is an Eclipse model 552/12 listed in the 1937 Radio Trade Annual with
same valve lineup you guys have agreed upon. Despite this model being a
console, l believe the 552 series chassis was used in a multitude of
Eclipse/Croyden models, including rebranded generic types (Apollo?).

I think you could well be right. Pity I can't find a schematic for the 552/12



Again, thanking all for their input, it is really helpful, interesting and much
appreciated.

cheers

Jon

OK that's sorted out the filament.

There's a couple of pins with no voltage supply still to sort out. The pins marked G2 and G4 you have them connected together via a long path of coils and R4, but there's no connection to a voltage.

I've often wondered how these 6V farm radios were powered, or, more particularly, how the 6V lead-acid battery was charged.

Swapping it over into the car or truck would be one way.

Or having two batteries, leaving one in town for charging and swapping over once a month on the trip into town.

I wonder if anyone ever attached a 6V car generator to a windmill? And if such an arrangement was ever used for lighting?

QUOTE:
OK that's sorted out the filament.

There's a couple of pins with no voltage supply still to sort out. The pins
marked G2 and G4 you have them connected together via a long path of coils and
R4, but there's no connection to a voltage.

yep you are right, I missed a resistor (R.5 in my notation) that connects that
to the HT line

I have redrawn the diagram again.
https://www.kellyavia.com/projects/radio/apollo/images/pdf/197.pdf

Hopefully this getting closer! Really appreciate the input.
Also assume it is OK to keep posting on this "introduction" thread?
Or should I start a new one in another category?

QUOTE:
I've often wondered how these 6V farm radios were powered, or, more particularly, how the 6V lead-acid battery was charged.

Swapping it over into the car or truck would be one way.

Or having two batteries, leaving one in town for charging and swapping over once a month on the trip into town.

I wonder if anyone ever attached a 6V car generator to a windmill? And if such an arrangement was ever used for lighting?

I lived on a property north of Bourke for a while in the 80s/early 90s,
one of the neighbouring homesteads had a windmill electrical generator that had
been used for powering lights in the homestead (Windlite?).

The homestead had burnt down several years before I lived there but the
windmill remained, now unused. It was a specialised mill designed as a
generator rather than a converted pumping windmill.

Prior to getting power most of the properties in the area ran a big old single
cylinder petrol generator that charged a bank of glass wet cell batteries that
supplied 32V to the homestead.

Right, you've done a general tidy-up as well.

It seems to be correct now, and should help you with the restoration.

Good luck !

I found a schematic for the Croyden/Eclipse 552 Series.

However, the schematic is barely legible. The schematic came from a disc sold by Kevin Chant over 20 years ago.

I can send a copy if anyone here wants to see if they can make sense of it.

Above is an trade advertisement from a 1937 Radio Retailer of Australia. The models shown are AC only.

I would be keen to have a look however does Kevin still supply the DVD? I would not want to circumvent work he has done, if he still sells the disk.