Gents,
I did a search on TROVE and found a picture of the Titan Tiny and it is smaller than this radio.

Rogermark says the rectifier is 6X5.

In the under-chassis photo, the figure 8 mains flex appears to connect to the primary of the power transformer, and the there are numerous secondary windings, including some that appear to go to the rectifier socket.

Turning out to be a bit of a mystery set this one.

This radio is very similar to my Sky Raider, model number unknown. Same "Tasma" style cabinet and the chassis has the same 3 blanked holes on the rear. Valve locations are the same and the chassis socket cut-outs are all for octal sockets.
My valve positions are: mixer is octal (unsure of type), IF is octal, 6AR7, output is 9 pin, 6M5 and the rectifier is 9 pin, 6V4. The 9 pin sockets are mounted on a filler panel under the octal size cut-outs.
Harold

Interesting that the KGH & Skyraider have a similar style chassis. A 6AR7GT could easily be used in place of a 6N8 or 6AD8. Same goes for a 6V4 & 6X5GT.

I was thinking that the KGH chassis could of been made by Calstan. It has the distinctive Calstan style serial number printed on the chassis. However, there are no Calstan circuits in the AORSM that match or are close.

Gandhn, is your Skyraider a dual-wave set?

and the [Sykraider] chassis has the same 3 blanked holes on the rear

Good observation. That "feature", for me at least, is a key distinction. Strikes me as a multi-purpose chassis.

Gandhn, is your Skyraider a dual-wave set?

Yes, MW and a short wave band.

Thanks to Gary for his remarks.

I have had a brief look at the wiring and can confirm that there is a conventional power transformer. CT secondary to anodes on 6X5 and winding for valve heaters.
I have already found one problem...the output transformer primary is open.
The volume control circuit is something I've never seen before. There is a 150k resistor from a ht point to one end of a 5k pot with the other end to chassis. the wiper contact goes off somewhere not yet traced out. Full clockwise of the pot ( max volume..?? ) is at the chassis/ground end of the pot.
Will do some more tracing soon but any thoughts..??
Assuming the output valve is a 6M5 then there is a 180 ohm resistor from cathode pin 3 to ground. There is a large value low voltage electro cap from pin8 to chassis. One would assume that this is a cathode bypass in a conventional circuit. Are there any 9 pin output valves with an internal cathode connection to pin 8..??

Love a challenge....!!

My equivalents manual has a note that *some* 6M5's have an internal connection from 3 to 6 and/or 8.

It appears to be the only candidate.

I assume the 'large, low-voltage cap' would be 25μF, 40V. It would almost certainly be dried up, it can safely be replaced with a modern 16V, 100μF unit. Just make sure the 180 ohm resistor is still 180 ohm.

The open-circuit transformer is going to be your major problem though. I can only wish you good luck with that!

Hi Everyone.
I have traced out the circuit diagram assuming that the valve lineup is 6AN7, 6N8, 6M5 with the installed rectifier being 6X5.
I have left out detail of the aerial and oscillator circuit as they seem quite convential.
Has anyone ever seen the strange volume control system..??
The volume control pot adjusts the cathode voltage on the mixer and IF stages. Can I assume that the DC component of the detector diode is used as some form of AGC as it would tend to vary the cathode voltage on the mixer and IF stage.
The detected audio looks like it gets to the grid of the 6N8 and the output is taken from the screen grid.
Has any one seen this before..??
As I mentioned before, I have an open circuit on the output transformer primary.
Does anyone know of or used the transformer available from RS Components part number 210-6475

http://au.rs-online.com/web/p/audio-transformers/2106475/

It seems to be a suitable replacement.
What is the purpose of the way they have configured the secondary of the second IF transformer..?? It doesn't seem to do much..??
Looking forward to your thoughts.
Roger.

KGH 52 Mantel Radio Circuit Diagram

You CANNOT Ground a live chassis: If Active & earth both end up together that equals Bang!

I note capacitor coupling on the antenna of the Titan Tiny set, that would also need investigating, as an insulation fail there could be fatal.

What I saw in the KGH seems to indicated a conventional transformer.

Beware: While we did build a few there are plenty of European & American sets with no transformer & in some, what looks like a transformer is a tapped ballast and these sets are treacherous.

Early sets had the volume in the cathode circuit in the RF section, with the era of that set, such a practice should have been discontinued.

In all later sets the volume control was between the first audio & OP valve. NB some did use feedback & the pot was tapped at around 40K from ground.

What you have is a set marketed and sold by Kieth Graham Harris he eventually owned titan radio of Bondi but in earlier days he bought sets, & slapped his name on the dial. He was a badge seller type salesman . Tasma used the case so too Skyraider written upon the dials.

These were radios just marketed under his name.

I may be able to help with a professionally rewound output transformer. Unhide your email address or send me an email to discuss.
Harold

Thanks to Gandhn and others following this thread.

Not sure it would be worth the hassle to rewind the output transformer as the one from RS Components should do the trick but it is good to know that there is a rewind service out there.

This is not going to be a pristine restoration so readily available components will have to do.
I do need a replacement for the output valve..6M5. Looking on the net, these seem to be a bit rare so I would have no problem using a substitute type. I have a 9 pin socket mounted to an adapter in an octal cutout so could go to a 6V6...any suggestions.
I also need a 6N8 for the IF amp.
The old electros will have to go and maybe some of the paper ducons, Likewise some of the old IRC 1 watt resistors.

Again, thanks to all for input to this thread.

Whilst I have managed to acquire a couple of 6M5's as spares, or replacements as I still fix sets, there is no need to change the socket, just the wiring.

Some of the Pentodes found in Triode Pentode tubes & with different labels are awfully similar to 6M5

I have used the Video output Pentode 6CK6 which is suspiciously electrically similar, to replace 6M5

The main trap is that pin 8 is an internal shield on it but not on 6M5. You have to tie pin 6 to the cathode (pin3) as the suppressor grid is tied to the cathode internally on 6M5 but not on 6CK6. Failure to do that will wreck the valve.

Marc

I'm sorry I wasn't clear about the transformer. I had one rewound a few months ago to have on hand, but never used it. I didn't think of RSC at the time.
Harold