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-   -   1939 KB 830 Receiver totally untouched. (https://www.vintage-radio.net/forum/showthread.php?t=154821)

electronicskip 12th Mar 2019 2:47 pm

1939 KB 830 Receiver totally untouched.
 
2 Attachment(s)
Yesterday I collected four old radios from a couple passing them on behalf of a deceased estate.
They were particularly pleased that they were going to an enthusiast rather than them being junked and some monies changed hands.

An unidentified radio of which I will post separately a Dynatron Elite, and a Philips 50s unit and the Kolster-brandes 830.

The main interest was the KB 830 Superhet receiver in totally untouched condition (one careful owner) including a first class condition instruction manual with the date of purchase of 15th sept 1939 .

I've not made any attempt to power it up obviously and I've had little experience with pre war radios.
Is there anything in particular I should be looking for ?

Thanks in advance.

crackle 12th Mar 2019 10:14 pm

Re: 1939 KB 830 Receiver totally untouched.
 
That looks like it has been well looked after, nice find.
It doesn't look like it needs it, but don't be tempted to clean the back of the dial, the white print can sometimes rub of easily.

Mike

electronicskip 13th Mar 2019 4:25 am

Re: 1939 KB 830 Receiver totally untouched.
 
On the back of the unit it seems to have multiple power settings so I'm presuming this model was exported quite a bit too?

Will open it up today and post a couple of pictures also.

crackle 13th Mar 2019 11:58 pm

Re: 1939 KB 830 Receiver totally untouched.
 
It possibly was sold outside of the UK, but normally KB's export sets had no LW, but were fitted with MW and two SW bands instead.
Were there still places around the UK where 110v mains was available?

Mike

Mike. Watterson 14th Mar 2019 12:26 pm

Re: 1939 KB 830 Receiver totally untouched.
 
Parts of France and Italy I think. Lots of French language LW in past and still at least one.

winston_1 14th Mar 2019 1:14 pm

Re: 1939 KB 830 Receiver totally untouched.
 
Don't think they used 110v. 127v was a standard there.

Mike. Watterson 14th Mar 2019 5:49 pm

Re: 1939 KB 830 Receiver totally untouched.
 
Maybe the taps are for 127V?
It certainly would not have been for N. America export as ITT had US models made in USA.

electronicskip 14th Mar 2019 6:30 pm

Re: 1939 KB 830 Receiver totally untouched.
 
1 Attachment(s)
Quote:

Originally Posted by winston_1 (Post 1128741)
Don't think they used 110v. 127v was a standard there.

Rear view of the radio showing the different voltages that can be selected via a switch, there is one for 125v .

julie_m 15th Mar 2019 7:40 pm

Re: 1939 KB 830 Receiver totally untouched.
 
On a three-phase supply, 127V phase-to-earth gives 220V phase-to-phase. Parts of the Continent were wired as 127/220V, and parts of Latin America still are: 120V appliances from the USA can usually be used on 127V, though motors will run at the wrong speed if the local frequency is 50 rather than 60Hz.

The UK standardised on 240/415V when it was decided to build the National Grid, but there were still local supplies of non-standard voltages and frequencies until the 1960s in some areas. Miners' cottages were often supplied with DC from the Pit's own supply.

Mike. Watterson 15th Mar 2019 8:33 pm

Re: 1939 KB 830 Receiver totally untouched.
 
Transformers though for 60Hz, if spec'd very tight, may be over-run at 50Hz as transformer power is related to frequency. Which is why SMPSUs (20kHz to 2MHz) were invented and the LOPT (10KHz or 15Khz approx instead of 50Hz) used for EHT instead of mains transformers.

The USA does use 220V approx for wired in major appliances and some maths indicates why USA doesn't have plug-in 2KW+ kettles or toasters like we do!

Ed_Dinning 16th Mar 2019 7:48 am

Re: 1939 KB 830 Receiver totally untouched.
 
Note that US does not use 3 phase domestically in normal circumstances, it uses biphase with 180 phase difference (110/220v) as in some rural areas of the UK where it is
230/460. (Centre point neutral system)

Ed

crackle 16th Mar 2019 10:02 am

Re: 1939 KB 830 Receiver totally untouched.
 
1 Attachment(s)
I was looking through my KB user instructions and found I don't have one for the KB 830. (it would be nice to have a copy for my records) But I do have instructions for the KB 835 which is an AC/DC version of the 830. The instructions also cover the KB 835-O which is basically the same model as the 835 but made for Overseas and has MW and 2 x SW bands.
So it would seem that if the KB 830 was intended for export then it probably would have had a suffix on the model number to denote the difference. It would also not have LW. There are a few exceptions like Norway, but mainly all the countries where LW was available, like mainly Europe, all have plenty of their own brands of radios, and export into these countries would have been difficult.
Where the manufacturers found a big market for export radios was in the Far East, Africa and other tropical countries. I believe that is the reason the suffix T was used by a few UK manufacturers to denote it was an export model.

Mike

crackle 16th Mar 2019 8:43 pm

Re: 1939 KB 830 Receiver totally untouched.
 
Here is a link to the restore I did on my KB 830. http://www.golbornevintageradio.co.u...d.php?tid=6241
There is not much information, it was a fairly straight forward repair.
Dont forget to replace the audio coupling cap going to the OP valve grid.

Thanks for the offer of the user instructions.
Mike

electronicskip 16th Mar 2019 9:13 pm

Re: 1939 KB 830 Receiver totally untouched.
 
Thanks for the link Mike, will take a look tomorrow when I start to examine the radio in detail.


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