Hi all, new member here. I recently acquired a STC model 732 console radio that I would love to restore. I am OK with a multimeter and a soldering iron but have no formal qualifications. I have begun work on the cabinet but the radio itself was missing all but one of its valves. I have joined HRSA and ordered valves from the valve bank. Does anybody have any further information about this model radio.
Thanks
Steve

Hello Sjn, welcome to steam radio.
The circuit for your radio is in Australian Official Radio Service Manual (AORSM), 1939, p271. I can email a copy for you if you don't already have it.
The radio was intended to run from a 6V battery, using a vibrator unit to produce the high tension voltage. There are people who manufacture power supplies for such as your radio - you will see ads in the HRSA Radio Waves magazine.

Some confusion here. AORSM shows the radio to have the valve line-up 6S7G, 6D8G, 1N5G, 1F7G, 1D5G, 1K5G, 6Z7G, 6N5, while Radio Museum has it as 6U7G, 6K8G, 6U7G, 6U7G, 6T5, 6Q7G, 6AG6G, 5Z4.

So the first thing to determine is, does your radio have a 240V plug? Then will get somewhere with the circuit.

So that you know what you are in for, you can't do better than watch the following by David Tipton of an STC 830 restoration.
https://www.youtube.com/watch?v=mXtKKJ3YS5A
https://www.youtube.com/watch?v=XaFsenbtrRE
https://www.youtube.com/watch?v=f-8hdQIzLI8

Mind you David has gone to the nth degree in this chassis restoration, but gives you an idea of how to get it going, which is the first thing to do, because there may be difficult to obtain components that have failed, such as mains transformer.

Note well Safety Warnings at the top of the page, and make up your mind if you have the experience for the job.

On a upbeat note, if the indicator valve in your radio is a working 6T5, it roughly doubles the value of the radio, because they are rare as hens' teeth.

Thanks for your replies, It is definitely 240volt and the valve line up is
6U7G, 6K8G, 6U7G, 6U7G, 6T5, 6Q7G, 6AG6G, 5Z4
Hope that clears up any confusion.

Steve

With that line-up it should work super well.

Good luck getting it going.

Oh, which valve is still there?

Based on the valve line-up I would guess that the correct circuit is labelled STC 734 on p 271 of 1939 AORSM. Although called 7 valve T/W vibrator the circuit shows a mains transformer! Looks like either AORSM or STC have made a mistake. Not unknown especially for STC. I can scan this for you this afternoon.

Once again thanks for all the comments. The valve that it came with is a 6U7G. Tha cap on top is hanging loose and it looks like I can also see hairline fracture. I ordered a replacement for it.
STC380 Re the indicator valve (magic eye) the only legible marking is the manufacture name "Brimar" any other lettering has been wiped off.
I have checked all over it with a magnifying glass but cannot find anything. As yet I don't know if it works because I haven't powered up the radio up yet.
it will be awesome if you could scan that for me. I have made my email address public in my profile. Also thank you for the YouTube links to the videos by David Tipton. (I wonder if he wants another one to check over🤔😉)

Steve

I have sent off scans from 1939 and 1940/41 AORSMs to your email address. 1939 has STC 732 as AC in the heading but vibrator model in the circuit, and STC 734 as a triplewave vibrator model in the heading but AC in the circuit. So looks like the headings were switched.

I will ask Brad to post these scans here as they may help someone else in the future.

Seeing as there was a possibility of an error in the 1939 edition I had a look in the 1940/41 edition and there was STC 732 triplewave AC, with circuit corresponding. So that looks definite.

Just adds to the history of the radio.

I can't speak for David, but he apparently undertakes work from repair to full restoration. So you can only ask him.

I hope I didn't put you off with reference to the safety warnings. I started off with student days electronic experience, articles from Electronics Australia as was and guidance from an electrical fitter father. If there are no curly problems you should be able to get it going. There are some on line articles on the subject which I will post some links for.

Good luck!

STC 732 Circuit Diagram - Part 1
STC 732 Circuit Diagram - Part 2

Here are some useful links. Other members of the forum may know of others.

https://hrsasa.asn.au/downloads/

https://nzvrs.com/peter-lankshear-articles/

http://thebakeliteradio.com/page102/page102.html

There are some real gurus on this forum (I don't consider myself one of them, though usually I can work things out eventually). So don't hesitate to ask for help.

Here is a link for the 6T5 valve, with images both working and not operating. The pin sticking up from the centre is the anode and if you have that it is a 6T5. Edit: Oops, no, the cathode

https://www.sm5cbw.se/tubes/htm/6t5.htm

6G5 and 6U5 valves are a plug in replacement, but with a different display.

Interesting display tube - despite all my years of valve collecting, I've never seen one of those.

In Australia only used by STC in the late thirties as far as I know. In the USA notably used by Zenith in one of their Shutterdial radios, as seen in The Waltons TV show.

https://artdecocollection.com/about-us/just-added/1938-zenith-walton-12-s-232-shutter-dial-tombstone-art-deco-radio/

Because of this they are in demand in the USA, NOS fetching hundreds of dollars. Even a worn out (faint glow) but working example can fetch $100.

I have sent a photo of the valve that I have to Brad for inclusion in this thread.

Documents uploaded to Post 9.

Photo uploaded to Post 14.