I have obtained an Air Chief radio I believe may be CS but doesn't match only CS pics I can find. Only identification I can see is the GMH Badge and a Serial Number. Top cover not wanting to be lifted and I am reluctant to try too hard at this stage. Hoped maybe some identification under the lid. I have several pics to assist. There is an aerial plus tuning and presume volume control.
Appreciate any advice where to go from here. (I am of the vintage that believes it is a Wireless)

Check Kevin Chant .com he specialises in car radios

Hi Graechel,

The best performing car radio EVER was my Air Chief in a 1972 GMH Belmont.

Any chance of a picture please? I may be able to pin an approx. date to it. Has it preset push button tuning?

BTW My Air Chief was made by AWA---if my memory isn't tricking me??

Thanks to both for response. I have forwarded 4 pics to Brad hopefully correctly following procedure.
No, there is no sign of push buttons and the tuner is rotary pot with a clock display.
The pics should help.
I will check kevinchant as well.
Again, Thanks.

Air Chief radios were made for NASCO, a GM division, by Radio Corporation (Astor).

There will be a two or three letter model ID stamped somewhere on the case or chassis. Once identified, I’m sure Kevin Chant will have a schematic.

Photos uploaded.

I am losing my touch. Should have been more observant. Believe is a power supply for a missing radio.
Weight should have been a clue. Probably includes a Dynamotor.
Still leaves question of what is the 2 knob control unit which "appears" to fit to the power supply.
Will keep digging and update.
Thanks for the interest.

Bowden cables are for tuning & likely on / off & volume.

Many of the factory workshop manuals had the details of the radio including circuit & fault finding: Seen them for Humpy Holden & my MKII Zephyr. Many were only politically different, sharing only a different facia.

Mud Wasp is an optional extra, current now, often found on the gills of a radiator, inside speakers etc.

CS & CR that I have serviced are more modern than that albeit they are universal on is 6V the other 12V with 50's valves. Check the number of pins on the valves

Marc

The last of the Air Chiefs were made by AWA but were originally made by Astor as AWA was supplying radios to Ford, and Holden probably didn't want the same in their cars due to the major rivalry between the two once-great marques.

BBTV, do you still have the Belmont? If so, check to see if it was made at Holden's Rosebery/Hillsdale/Pagewood (Sydney) assembly plant. It would have made sense for Holden to install radios made only a few km away by that stage as they were building for a third of the local market at the time. The middle part of the chassis number will denote the factory the car was made at. The chassis number was later replaced by a vehicle identity number and this number won't tell you where a more modern Holden was made but in 1972 things were easier.

A ready reckoner is at https://www.uniquecarsandparts.com.au/holden_identification

One of Zephyr's (have one not in vehicle) is Radiomobile. Which was HMV & Smith's: Bit like RCA

No sadly, the Belmont ended up in the wreckers a long time ago. However, when I first bought it, it did have NSW rego plates, I remember having to wait while it got its VIC plates.

I have a similar radio stashed away somewhere. Mine is missing the Bowden cables and under-dash unit. It's probably pre-WW2. Mine (Branded "Hastings Deering" - a Ford dealer) definitely is. A look inside should tell.

"General Motors Holden" used to assemble Chevrolets well before the Holden car appeared. Your radio probably dates from that period.

I believe your radio is an Astor "CG" - here's a link to the circuit:

https://www.kevinchant.com/uploads/7/1/0/8/7108231/cg.pdf

Looks like it originally used an electrodynamic speaker with a low voltage field coil. You could of course use a modern PM speaker.

The hunt continues.
Now appears need to open the case so I'm appealing to braver and more experienced souls than me.
Difficulty removing top cover (4th pic). One end moves slightly (2-3mm) and appears to be held about half way down cover.
Top end in pic is one that moves. Bottom hardly any movement.
Is it likely the 2 large mounting bolts extend through to the cover and are what is holding it in place?

I'm prepared to undo to see what happens but like to hasten slowly at times like this..
Caution heightened as appears bolts may also be a power source. Earthing maybe??
I also feel unlikely any of the fittings shown around the GMH logo would need to be removed but I have been known to be wrong.

Any thoughts before I bite the bullet??

Try removing the nuts from the mounting studs on the other side of the case. It's possible those studs go right through and are welded to the underside of the top cover.

This is a vehicle mounted radio, so that kind of mounting strength wouldn't be surprising.

BTW, when you get that far, the rectifier valve type isn't marked on the circuit. If it has a 5 pin socket it will be an 84, AKA 6Z4. If it has an octal socket it will be a 6X5(G or GT).

Note that a search for 6Z4 will bring up a Russian / Chines tube which is entirely different.Here's the one you want:

https://frank.pocnet.net/sheets/021/8/84.pdf

There is a capacitor wired between the anodes of that rectifier. This is a VERY CRITICAL and hard-working part in any vibrator supply and it frequently fails. If it fails O/C, the vibrator, the vibrator transformer, rectifier socket and even the rectifier valve itself will be damaged. It must be a special high current capacitor. Many radios of that vintage used a large mica cap that was screwed to the chassis. These are generally good. Wax paper - almost certainly bad.

The value of this cap is hard to read in the schematic but it looks like .004(uF). More commonly used caps in later radios were .0082μF 2kV. If what's there is a paper cap, you should replace it before applying 6 volt power to the radio. Two .01 or .015 1kV film caps connected in series with the CT to the CT of the transformer will work.

Other than that, the radio is pretty conventional and the usual issues with paper capacitors and electrolytics apply.

Kevin Chant has solid state vibrator replacements.

Thanks for the help and cover is now off.
The 2 big mounting bolts were removed but I then noticed 2 other screws and off it came. Amazing what obvious stuff so easily missed.
Can find no obvious indication of manufacturer, Model etc . Only a Serial number. 0918
Inside cover is a sticker in a position making it almost impossible to read but appears to be a Certificate
stating conforms with Broadcast regulations etc . There is an overprint of ARTS&P.
I am chasing to try and find more on this sticker, Yellow with 6 in top left and C 1120 in bottom right.

For moment will stick with Ian's CG and build on that.

Anyone have any further interest in this Radio??

Have sent Brad a couple of pics.

This episode has bought back memories but also highlights how much I have forgotten.

Again thanks to all.