New Pup KB 362

[rockinmark]

I saved this radio from going into the rubbish tip looking at it I thought it was a kb397 I don't know that much but when I opened it up I thought a lump was missing. When looking at the wires it looks like it connects to batteries after searching a bit more I found the kb362 and says it runs from batteries. I would not know where to start with this set. I was wondering if anyone live within a driving distance from st albans that I could take it to and could explain how it works some of the leads still have markings on like ht+ ect.

[Cobaltblue]

The leads are colour coded as well as marked.

HT + (light blue) and HT - ( Black) are the HT supply 120V for this set so 13 PP3's in series is close enough.

LT + (Red) LT - (Black) 2V DC you will need something like a Cyclon for this. https://www.allbatteries.co.uk/cyclo...-acp3701b.html

GB - (Green) this needs 6V at very little current the Positive connection goes to the HT-

You could make up a simple DC power supply to replace all the batteries.

HT is High Tenison and LT is Low Tension GB is Grid Bias.

Its all pretty clear on the circuit diagram: https://www.service-data.com/product...67/4049/m13067

Cheers

Mike T

[Ed_Dinning]

Hi Mark, a warning on this one NEVER operate without the GB battery connected and always switch off if changing GB tappings. This has similar consequences to a very leaky audio coupling cap.

Nice set, should be easy to restore, Ed

[rockinmark]

The other set that I got was a cossor 483 which is a battery set as well just wanted to save both from skip think both are beyond me I just thought it was a shame

[Cobaltblue]

Hi Mark if you decide you want to move on the Cossor 483 please let me know.
The 483 is 3/4 the way down on the right had side here :
http://www.cossor.co.uk/rogues-gallary
Cheers
Mike T

[crackle]

Yes it should be easy to get working. Just the single RF valve and audio preamp valve and output pentode valve.
Permanent magnet speaker with speaker transformer, no inter valve transformers on this set to worry about, its capacitor coupled throughout.
Change C4, C5, C6 and C9 initially and see how it works. Then change any others on the front end which test as very leaky.
A nice long and high wire aerial will give good results on this radio.
An earth not too essential but may help improve reception if the aerial is short.

Mike

[crackle]

Here is a promotional photo of the KB 362. http://www.kbmuseum.org.uk/documents...otos%20010.png
I wonder how may Bargees actually bought them.
Mike

[rockinmark]

That promotional photo Mike makes sense I really couldn't see the point of making a set that's battery powered when it was so heavy and don't even have a handle. Cabaltblue Mike I only got them home last night the paint work on the cossor is in a very poor state one knob is missing from side but everything else seems to be there. I cant see how I can recreate the pattern in the paint work both are nice looking sets so at the moment I would like to wait and see if I can find anybody nearby that could show me what I need I'm not good at reading schematics maybe I'm stupid I should have learnt this stuff when I was younger lol anyway thanks it a very interesting read for me. With battery radios that I never thought existed back in the 1930s that has my mind going, and just read about life before everyone had electricity
Mark

[Herald1360]

Early domestic radios were pretty much all battery operated until the late '20s. After that there was still a steady market in more rural areas yet to get mains electricity. Portable (valve) sets of course continued until their market was killed off by transistor sets which were much cheaper on battery use.

[Cobaltblue]

The "Walnut Woodgrain" on these sets is unfortunately fake, its plain white wood and the "grain" was added by a photographic process.
If your going to restore it your going to need to restore the "grain effect" by hand.

You probably don't realise but even up to the early 1970's some rural communities had no mains power.
Battery sets were still common while I was at school in the 1960's as most of the farms still had no mains power or relied on things like the Lister Start-O-Matic as was the case at my friends house.
during the 1930's in Rural Cornwall Battery sets were the Norm certainly for both my parents
ISTR reading somewhere that Bolventor was the last village in England to be connected to mains power in 1972 ( I may have mis-remembered I will ask the oracle on all things Power in Cornwall when I get a chance).

Cheers
Mike T

[rockinmark]

I have taken the radio apart and gave it a quick clean to get the cobwebs off. All the PVC cables look all black but as Mike has said they should be coloured coded as I have to change I will use the right colours. Will 2mm cables be ok. The rest of cables are cloth covered with they be ok to leave I downloaded the schematics but I was going to start with the easy stuff I know I can do without help first
Mark

[crackle]

Is that 2mm squared copper conductor, or 2mm diameter across the insulation.
I would think 0.75mm sq conductor PVC multi stranded flexible wire would be more than enough, none of the wires have to carry much power. The heater wiring only has to carry 0.4 amps.
I believe the original wires to the batteries would have been cotton covered with a rubber outer covering. The rubber will have gone brittle and probably crumbling away.
The cloth covered cables under the chassis should be OK if they are not disturbed to much.

Mike

[rockinmark]

What should I change the c4, 5, 6, and 9 capacitors for?does voltage matter.. I have not taken the cardboard bit apart yet to see what is there I m I right in thinking everything is sandwiched between it
Mark

[Herald1360]

Leaky C4 will upset biassing on V2 but probably wouldn't actually damage anything.
Leaky C5 will turn on output valve too hard to its detriment and possibly the output transformer.
Leaky C6 could take out the output transformer if it's seriously so.
Leaky C9 will upset voltages on V1 and could possibly cook R8.

Capacities can be same as specced- they're all standard values. Going a bit higher won't hurt.
Voltage rating should be higher than 120V, C6 at least 250V. A safer connection for C6 would be across the output transformer primary rather than to chassis.

[crackle]

Originally Posted by rockinmark

I have not taken the cardboard bit apart yet to see what is there I m I right in thinking everything is sandwiched between it
Mark

Not quite following this statement, what cardboard bit is that, maybe you mean the card circuit board. There should be no need to take this apart, you could just clip off the wires very close to the capacitor you are changing, leaving as long a length of wire to solder the new capacitor leads to as possible.
Some people try to hide the new capacitors in the old capacitor tubes, after emptying out the old contents, but this can get a bit messy and is not essential.
C4, 5 & 6 can all be 0.001uF, (or 1nF) I would use 630v polyester types, they are readily available in small quantities on Ebay
C9 is 0.1uF I would also use 630v polyester type.

If you are wondering about the value of C1, a micro microfarad is the same as a pico farad, or in other words 9pF in the case of C1. But I do not think you will need to change that one, or C2 either.

Mike

[rockinmark]

It looks like cardboard see photos maybe its called some other name but that a easier way thanks Mike and chris

[rockinmark]

Why are some of them plastic c2 c3 and c6 because I'm somewhat new to this I have never seen them

[crackle]

KB often used small value capacitors housed in a black plastic tube with the ends sealed with bitumen.
These are also wax paper types and will be leaky to some extent but may not be critical in C2 & C3 positions. C6 is more important as Chris mentioned earlier, if this leaks too much DC then it may burn out the OP transformer primary. Then it becomes expensive.

By the way C1 may well be simply 2 enabled wires twisted together and coiled up. This should not need changing.

Mike

[rockinmark]

This is a up date about this radio. First of I would like to thank everybody on this forum for the help and support I have finished the electrics and have finished the cabinet I am pleased with the overall out come so far.
This is where I need help and was wondering if anyone lives not to far from the Hertfordshire area that has some way of powering it up for me and help how I go about it.
I could come to you or you come to mine

Thanks
Mark

[davebms]

hello all im.. in ware Hertfordshire, may be a bit of a trip for you ?
I have the battery's required and an aerial (not a very good one but it works) I am not very experienced but.. up to you

dave