Re post #12 and Calstan.

Brad, you have a Calstan on this site!
Special projects Calstan 559 8th June 2016.

Also featured in Silicon Chip May 2022 in the Vintage radio section.

Cheers, Fred.

Happy New Year Fred! How's it going?

Yes Fred that's probably Brad's hospital radio, but nothing like the HG Palmer.
Somebody paid to put injection molding dies down for that HG Palmer radio.
Same with the mask tooling for the TV range at the time.
Looks like there was money for an industrial designer too, in both cases.

I still think it's KGH, by process of elimination and because KGH made TVs and even transistor radios for Henry Gordon at the time.

Oh that resistor should be 270 ohm. Power supply goes thus:

Half wave rectifier, silicon diode.
1st filter electro poking through the chassis. Supplies speaker transformer.
270 ohm resistor from here to 2nd filter, 6GW8 G2 and remainder of radio.

Reason I think it's 270 ohms is that a higher value would dissipate too much power for a half watt resistor to handle. Even then, it's marginal. Replace it with a 270 ohm 1 watt.

My guess is you'll find a low HT voltage in this radio, just like Kriesler did in the 11/99. Keeps the heat down.

In fact, if you want a circuit, the later version of the 11/99 would be very close, bar the use of the 6GV8, which has different pin connections.

G'day Fred,

I'd long forgotten about that. Yes, that is one of the models featured at the former Gladesville site.

The other valve radios there were my own HMV model 886 which was a daily listen at my workbench and a HMV model C23 in the Transport Manager's office. His was busted though and despite repeated encouragement from me, he refused to get it fixed and claimed that I was too young to fix valve radios.

Down the track he had reason to stop in at the electricians' workshop and noticed mine on the bench blaring away and he did ask how it was still working and I simply said, "because I got it going again". A happy man, he wasn't. Being one to rub the salt into wounds, I also let him know that I had thirty more valve radios in my room in the staff quarters and the collection was growing at the rate of around one every six weeks.

Thanks Ian for the info on the 270 Ohm resistor.

I've checked out the cct for the 11-99 & this is very close to what I have, except for the obvious differences in output stage & power supply.

Between what I have already drawn & the front end of the Kriesler, I will be able to cobble a circuit together for future reference.

Thanks again.

On the subject of the 11-99, I put a post on the US site proposing it as the last valve mantle radio in production anywhere in the world.

It looks like that is the case.

Fitting model number. Did they know?

Clearly for what its worth is a set from 1965, about the time HG Palmer went belly up with unbelievable debt at the time.

https://www.radiomuseum.org/r/hgpalmer_rm1r_205.html

Now my method of reverse engineering involves drawing the principle bits in their location first. I.e. coils tubes transformers etc. Colour is a big help "B+" reds, orange, blue for screens; Dark "B-" black brown s & green for heaters. Then play join the dots.

From that layout diagram you can usually produce the circuit diagram. You do that even if its looking to be wired wrong.

Once you have the circuit only then do you correct it, then the radio. Not before.

I actually bought an AutoCAD in the late 90's to do this.

Marc

Have a look at a KGH 10/14A

I would suspect that it will have the same front end but instead of a single triode it gets a triode pentode and a non-tube rectifier.

Marc

Marc I used to use AutoCad MANY years ago to do schematics and PCBs.

These days Protel / Altium is SO much better suited to the task though. But back then AutoCad was the only choice you had.

I used it to do some quite complex PCBs in the days when everyone else was using stick-on footprints and black tape.

One feature AutoCad has is the Stretch command, which lets you easily make room for extra parts. It's also good for neatening things up. All the selected lines stay connected while you move stuff around to make space. This works if you have used Polylines (pline command)

Have you ever tried the LTSpice schematic editor? It's a freebie and allows you to put a schematic together and edit it very quickly. And of course to check your circuit to see how it works without actually having to build it.