Its very quiet, but could this terrible radio be made to work?

[radioman]

I certainly agree about the speaker fret.... if this was mine and I managed to get it working, I think I'd modify the cabinet to make it more presentable... or at least come up with a more pleasing fret design !
I don't recognise the chassis either : maybe it originally had a bakelite cabinet that got smashed and so a replacement wooden one was constructed.
Good luck getting it going Sam !

Andy

[Mark Hennessy]

From what I can see, if homemade, it's not a bad job. Curving the cabinet, getting those very sharp lines in the fret - that would have been quite the project back in the day... Perhaps it's more obvious when you can see more of it, but whoever did it certainly wasn't going for the easiest options possible!

[boater sam]

The speaker fret is not fabric but woven fibre similar to that used on The Goblin Timespots, quite hard and coarse.
The tuner is unusual, with the use of a lamp moving with the capacitor and the lighted slot scanning the tuning scale. The all metal slow motion drive is working well.

[boater sam]

From what I can see, if homemade, it's not a bad job. Curving the cabinet, getting those very sharp lines in the fret - that would have been quite the project back in the day... Perhaps it's more obvious when you can see more of it, but whoever did it certainly wasn't going for the easiest options possible!

I will post a photo of the inside Mark and you may have a change of opinion, its rough from the back and inside! The front panel is completely flat, again very simple. The cutting of the fretwork is very crisp however. An unusual pattern, not seen that before.
There is a back board, second use plywood and very simple with holes for ventilation, definitely not professional.
That big Ferranti choke brings back memories of when I worked in the Moston factory where these were made, a bit before my time.
The socket on the back of the chassis is mains I think, heaven knows what for, a record player maybe?

[boater sam]

The socket on the rear is not mains but an audio input via the left hand potentiometer, 650k ohm, which is crudely wired as a rheostat to the volume control in the grid of the 6V6G output valve.
Its all messy screened wire so I will likely remove it all before trying power.

   
 
The mains transformer I have checked with an ohm meter. It has a primary of 27 ohms, the 6.3v, the 5v and the center tapped HT winding all show the expected resistances. The knot of unconnected wire under he transformer against the back of the chassis look to be unused primary mains voltage tappings.
 Isn't life better when you can post pix?
 Thanks all for your interest and input.
More will follow............

Sam.

[Mike Watterson]

I've 1935 HMV radiogram that has a light moving and casts a spot with a line on the scale.

I'd not change the fret but simply clean up the case.

I think I've seen much worse and it should restore nicely. I've seen more primitive "commercial" cases such as the too late UK Civilian WWII utility radio.

Looking forward to the story, Sam.

[boater sam]

Looking at the spacing of the control shafts it is obvious that the rheostat has been added after the chassis was first built and that the associated wiring is also not original. So I am not adverse to removing what is a useless addition. A purpose for the hole in the cabinet will need to be found.

The output valve grid coupling capacitor, 0.01mf, is slightly leaking, it will be monitored as soon as power is applied and if the grid voltage gets a bit too positive it will be changed.

The HT reservoir and smoothing electrolytic capacitors in the can are suspected capable of doing very little, the can will likely need to be opened and re-stuffed. I prefer to do this rather than put new ones under the chassis, there is insufficient room there anyway.

There is another slim ally can with several capacitors inside. These look to be non-electrolytic and will get checked as will all other capacitors. The can will remain in situ no matter what though.

Resistors are a mix of old carbon 'dog bones' and later ceramic cased carbon, they will be checked as I come to them.

The valves all look mechanically good, a couple have loose bases which will be re-glued.

I will need to find a speaker and output transformer for testing, perhaps taking the output from the output valve into another receiver temporarily.

Sam.

[Kalee20]

Most curious!

As others have said, the speaker aperture fretwork is remarkable - it looks machine cut (or laser cut!) and is very crisp.

The chassis looks to have been machine-punched too, and folded.

By contrast, the travelling lamp on the tuning scale looks horrid!

How many wavebands does it have?

[Paul_RK]

How many wavebands does it have?

Just the standard LW/MW/SW from the dial.

I admit to rather liking the speaker fret, odd though to see a feature whose popularity faded rapidly somewhere around the middle 1930s in what looks to be a post-WWII radio. Maybe an enthusiastic Hobbies fretsaw owner who was determined to use his skill on the cabinet regardless of the fashion of the day, and why not?

Paul

[Mike Watterson]

The output valve grid coupling capacitor, 0.01mf, is slightly leaking, it will be monitored as soon as power is applied and if the grid voltage gets a bit too positive it will be changed.

No point in not changing that immediately.
Also any paper caps on screen grids as the leakage will kill gain.

Without a 400V leakage tester, one solution is to remove all the valves and apply HT. Then check the voltages. All paper dielectric caps, unless hermetically sealed cans, leak badly after about 10 years. Water dissolves in the oil/wax/paraffin and into the paper. They are often OK at transistor radio voltages, but not at 50V +