Hi there,
I’m repairing a Royaltone radiogram and can’t find any info about the company including and schematics for them.
Can anyone assist with information on them?
Thx
Scott

Got a photo of it? It might be something else rebadged.

Royaltone has the ring of a house brand name, and seems it was according to the Radiomuseum:

QUOTE: Name: Goblin, Royaltone (Brands), Royal Art Furnishings Pty. Ltd.; Sydney, NSW (AUS)

Royal Art Furnishings Pty. Ltd.
280-282 Pitt Street, Sydney, NSW

Royal Art Furnishings, a Sydney furniture and white goods retailer advertised Goblin Brand radios from 1940/50 followed by Royaltone branded radiograms in the 1950’s. [1][2]

The actual manufacturer of these re-branded radios and radiograms is unknown at this stage.


History:

[1] The Sun (NSW) Jan 7, 1940, Page 11.
[2] Truth (NSW) Jan 17, 1954, Page 44.

Hi gents,
Thanks for the replies. I have taken some pictures of the chassis and turntable. I think the process is to send them to Brad for uploading??
The valve lineup is as follows:
6X4, 6BV7, 7G7, 7C7, 6BE6. (The 7G7 & 7C7 are hard to read)
Once I know how to upload pics, I’ll post them.
Cheers

Late 50s, early 60s. Those Loc-fit tubes were rarely seen here. Sounds like a small manufacturer that got a special deal on them.

I'm tipping KG Harris, that is the sort of thing they used to do.

May have been Astor that must have got a good deal on EF 50 Loctal's as they appeared in their IF's of some models.

Once I know how to upload pics, I’ll post them.

There is no such facility on here. You have to send them to the site owner. Use Contact Administrator

That's a bizarre line-up. Nothing I can find matches it. As above, sounds like a small operator.

Thanks guys, I’ve emailed some pics to Brad, once they’re up it will be interesting to hear your thoughts
Cheers

Photos uploaded.

I've never seen any of those 7-series valves before. If it wasn't for them I'd say it's a standard 5-valve radio.

Replace those 4 wax ducon capacitors, check the transformers for continuity, and it should hopefully work.

Thanks, that’s the plan though there seems to be a short somewhere. There are 2 x 120ohm resistors, 1 of which goes to the negative side of the 24μF electrolytic cap to ground. When switched on, it immediately overheats. The dial lights are also dim. Removing the 6X4 rectifier valve sees the dial lights return to normal brightness and no volts at the 24μF cap. I’d like to know what voltage should be there as there may be an issue with the transformer itself. The 24μF has been replaced.

I’d like to know what voltage should be there

In the absence of a schematic, 6X4 data here: http://www.r-type.org/exhib/aaa0233.htm

Those figures should *not* be exceeded.

Suggest searching data sheets for the other valves as well, for guidance as to max operating characteristics.

I think we need to do some tests with the 6X4 out. Firstly power-off, unplug mains cord. Multimeter to ohms. Check resistance between 24μF - 120 ohm junction (I'll call this point X from now), and each of the 6X4 anodes. Should be the same for each anode. Now measure between one anode and the other - should be twice as much resistance. Lastly, measure between point X and chassis - 120 ohms.


Now, multimeter to volts AC, leave 6X4 out, power on. Measure volts on the anodes, should be around 200 each (very approximate). Volts at point X, around zero.


Finally, multimeter to volts DC, put 6X4 in, power on. You should have approx 200-250 volts on the positive (6X4) end of the 24μF, and a few volts negative at point X. Make sure the cap is rated at least 350 volts, and is the right way around (it appears to be).

The negative voltage might be used as the grid bias of the 6BV7. If it is, you'll see a small size high value resistor (perhaps 470K) from point X, going to the 6BV7 grid.

The other thing I noticed is an old chassis-mounted filter capacitor is being used as a tie point. It looks like the high-voltage end has been isolated, but has it? Those old things tend to short out eventually.

Let us know what you find. Since the lights are dimming, switch off as soon as possible - we don't want to damage the transformer.

Thanks for be that, I changed the 24μF cap it’s 600v rated.
I’m just using the negative terminal on the old cap to keep things tidy. The positive side of the 24μF cap goes to the 6X4, a tap of the transformer plus to the OP transformer. The negative side goes to the 120ohm resistor, and through a couple of resistors to the 6BV7.
As per my previous post, the 120ohm resistor overheats and probably needs replacement as it’s pretty burned. I can replace it with a 5watt 120ohm which hopefully won’t fry.
There’s something loading the supply down as the dial lamps are dim, if I remove the 6X4, the lamps are back to normal.

If there is no PSU circuit draw it. If the set is back biased, the CT will ground via the 120R. the 24μF cap is from CT to ground. If there is a cap CT to chassis It will be negative to CT, positive to chassis.