Hello everyone I have recently purchased this STC valve radio and the electrical side of it is in rather good condition, however my concern with the set is, what voltage is it meant to be running, instinct tells me it should be 240v however when I purchased the radio the lead had two crocodile clips on it? this has made me second guess my self.

The set its self has 3 transformers and 5 valves. I can take more photos. any information on this set would be greatly appreciated.
Cheers, Mitch

Photos would be a good idea, plus if you could give us the valve types, that would make things a lot easier.

Hey there, I have emailed the photos to the admin as per instructions ? is there another way to post them ?

the first valve from the set is a
6G6G Brimar

next is a 1C7G Radiotron.

next is a 1F7GH Brimar.

and a 1D5 GR Brimar.

I am accessing the others as we speak.

thanks for your reply
the unit is an stc
code: 414

23853

The 1-volt valves make me think it's a battery model.

Whatever you do, DO NOT connect it to 240 volts, because all the valves will be destroyed.

That's what I thought ! would we be talking 32 volts or 12 volts ?
thank you heaps

Not sure yet, let's wait for one of the others to link a schematic, or may have knowledge of that model.

Images are usually posted by 22:00 NSW time on the day they are e-mailed. Often it is slightly earlier but if I am out of town it can be up to 48 hours. I'll be home tonight so they should be up before the deadline.

Hey Brad thank you for the info
Cheers, Mitch

Are we sure about 414? Most of those like 415 were 6V That voltage should be on the vibrator if its not missing?

Did you count the vibrator as a valve it will have a fully metal jacket.

Be very careful replacing caps in the power supply, it is a resonant circuit and there may be capacitors rated at several hundred volts perhaps 1KV. And that is what you replace them with, not less.

Marc

Hello , the vibrator is present and rated at 6 volts, however given the presents of a transformer I wasn't sure.
and the rear of the set is stamped 414.
thanks, mitch

The transformer is likely centre tapped on both sides and is actually part of the vibrator circuit.

As the vibrator (which may need servicing) oscillates it switches in a similar fashion to the points in a Kettering automotive ignition, producing a square wave (on / off) like a Multi-vibrator at around 120Hz and that is the wave that generates the "B" voltage. Some have a synchronous vibrator and no rectifier valve and this is one of them.

One does not run those transformers on 50Hz.

Just ran the set on six volts the vibrator runs and the 1f7 1d5 and 1f7 heat however the
6g6 remains un heated .
There is humming through the speaker.

Sounds promising.

I had to use the 415 schematic, and it looks like the 6G6G heater is directly connected to your 6 volt supply. The fact that the speaker hums seems to indicate there is some activity around the 6G6G, although what exactly, remains unclear.

Does turning the volume up and down make any difference?

Be careful with the tone control. It appears to carry the HT, so touching its terminals will provide a shocking experience.

Kevin Chant has the STC 414 R & S schematic:

http://www.kevinchant.com/uploads/7/1/0/8/7108231/414r_414s.pdf

It looks very similar to the 415. The only difference I can see at a quick glance is the tone control.

Thanks guys this information is of great help are there any further tips on where to start looking for
Faults, volume has no effect on the humming. One thing I have noticed that the set appears to no turn off with the switch and the dial lights are present and not blown but fail to light