Hi folks

I have a "Relton" set that looks like an identical cabinet to an late 1940s Airzone but I can't find a circuit diagram in the AORSM.
The valve lineup is 6A8, 6G8, 6V6, 6X5.
I have replaced all the caps and some of the dodgier looking resistors going by the component markings but I'm only getting weak reception from the strong local stations.

Does anyone have any suggestions for this "L Plate" restorer?

Thanks
Laurie

Airzone was one of many that offered chasses that could be put into a variety of cabinets. EMMCO circuits tend to be hard to come by, however that is a very common valve line up. You may find several circuits in AORSM's that use that combination. It is possibly mid 30"s The set is reflexed to save a valve.

Just because a resistor looks dodgy does not mean it was. You actually have to measure it and doing that with it in circuit can lead to errors. Some early resistors did not use the RMA system.

Assuming that you used the right parts, sets can often be "deaf" as someone messed with the adjustments and HMV for one, point out that if you changed RF components, you are advised to re-align it. I always do.

The Airzone I sent home Sat was deaf when I powered it. Predictably the IF's were miles out however once adjusted, that solved the problem. Before fault finding, alignment is the next item.

If you take a photo of its chassis we might be able to recognise it?

Marc

Gday Marc - I somehow missed your reply until now.

The radio in question is the same as this one:

http://www.carters.com.au/index.cfm/item/328298-radio-relton-circa-1950-brown-case-with-red-knobs-height-165-cm/.

It's the only reference I can find.

I will try to upload my pic of the chassis (has number 1339 stamped on it next to the ARTS&P sticker).

Appreciate your help.

Regards

Laurie

Here are some sets with that valve line-up:

Brand, Model, Year

Airzone, 458, 1941
Airzone, 458, 1946
Airzone, 458, 1947
AWA, 500M, 1946
AWA, 500MY, 1946
AWA, 506M, 1946
HMV, 46B, 1947
HMV, 46W, 1947
Hotpoint, E64ME, 1946
Hotpoint, F64ME, 1946
Hotpoint, G64ME, 1946
Hotpoint, G64MEY, 1947
Hotpoint, H54ME, 1949
Malvern Star, 458, 1946
Peal, P458, 1946
STC, C141, 1947

Thanks for that - the Airzone 458 looks promising but the component values are varied. I'll check the others out too and guess I need to trace out the circuit.

I wish they'd labelled things a bit better back in the day...you need to be a bit of a Sherlock Holmes.

Laurie

Also my set has a tone control pot which doesn't seem to be in the Airzones.

This radio is a bit of a mystery. Page 241 of Radio Days shows blue, green and brown versions of your radio with the date being c1950-1952 but no other info. This puts it at a much later date than the radios GTC listed in post #4 and is a strange valve linup to be using into the 1950's. Most manufacturers were changing over to miniatures by then. None of the AWA's or Hotpoint's had a tone control and the photos definitely don't look like an AWA chassis..

I am wondering if there are some Herrings here. The ARTS & P label looks like the base of a "G". If so that is 1940's & consistent with the valves.

Have a look at the patent numbers for dates. Quite often the speaker transformers had a date on the edge. I have a 1940's Philips here waiting shipping out. that has similar looking cloth wire which has a white rubber core insulation.

I have not seen many 1940's sets with plastic wire on the transformer, is that a repair? Tuning Gang looks a bit like the common Stromberg Carlson that everyone & the dog used.

Not too many used that style of transformer, nor IFT's with former bolts that long. That tatty dial indicator needle effort, I have seen on an Airzone Midget.

Paint is very like Tasma. Resistors & caps can be a clue as to era.

Marc

Relton Radio were advertising for radio wirers in the Sydney Morning Herald classifieds, April 1950. This suggests that they were manufacturers of radios and not selling re-branded generic Airzones despite using Airzone cabinets. In fact Relton were licenced by the ARTS&P to manufacture radios in 1934, but no mention in 1939 - unless they were licenced under a different name. Bell Radio in NZ also used Airzone bakelite cabinets right up until the 1970's, albeit with transistor radio chassis inside!

First mention of Relton Radio in Trove is June 1932 and the address was 15 Park St., Sydney. By 1950 Relton were situated at Cameo House, 305 Pitt. St. In 1954 Relton were at 263 Liverpool Rd., Ashfield.

Unfortunately, a lot of the smaller radio outfits (unless they were in Queensland!) didn't make it to the AORSM.

The mystery deepens.

I found this "Cavalier" with identical cabinet while searching around:

http://www.thebakeliteradio.com/page120/page120.html.

Does that throw any additional light or further confuse matters?

Marc - the transformer doesn't look like its been repaired. I'll have a closer look for dates & pat numbers on other components.

The only references to "Cavalier" on Radiomuseum are in relation to HMV in 1965/6.

It might just be worth checking the schematics of those HMV references I gave you earlier.

Cavalier radios were the house brand for Winns Department Stores of Sydney & Newcastle. The Relton in Radio Days & the Cavalier in thebakeliteradio.com are identical. If Relton were, as suggested, manufacturing radios, it is possible they also made generic radios for others like Winns

Just an update - I found "22 May 1947" stamped on the speaker rim.
The reason I took it out was because the spkr transformer primary went open circuit ..maybe I blew it up while fiddling to attach a meter to the output valve plate pin!
The radio now works up to a point- very noisy- and much louder with a finger on the aerial.
...I'm still learning...

Cheers

Did you check any of the schematics of those other models from that time?

I went right through the AORSM on disk and couldn't find a match. I couldn't see any with the same valve line-up that had a tone pot.
Once I have a long antenna attached the radio works but very noisy - and only at full volume. Nothing is heard on the volume setting until virtually full on. Does the same with a substituted pot.
Meanwhile I've put it back into its cabinet and maybe I'll attack it again when I've learnt bit more!
Thanks for everyone's help - see you in Canberra.