Cossor 483

[rockinmark]

Hi all trying to find out what I replace this capacitor with c33. It is huge says its 2 mfd. Why is it so big, I know the old capacitors are much bigger but I have never seen a paper capacitor that big

Mark

[cathoderay57]

Hi Mark, it's a pre WW2 set and I guess it was the best that technology of the time could achieve using metal foil and waxed paper dielectric. Also it appears to be across the HT supply so is large enough to withstand the voltage (at the time, probably not any longer!). You could restuff it but it's a messy business. If it were me I'd disconnect it leaving it physically in place for appearance's sake, and conceal a modern miniature component (rated at least 1.5 times the max HT voltage) behind it. The type of replacement capacitor doesn't matter much, electrolytic, polyester or whatever. Cheers, Jerry

[Cobaltblue]

It's a battery set and it's HT decoupling.
As the HT battery ages its internal impedance increases making motor boating more likely.

You can use an electrolytic if you don't have a suitable polyester cap.

Nice set.

Cheers Mike T

[Herald1360]

If you want something modern and similar in size, a metallised polypropylene 2uF 450V motor run capacitor could be a good bet.


Something like this: https://www.ebay.co.uk/itm/2uF-Motor...QAAMXQ1PNRZkA0


Wrapped in some brown waxed card it would look the part quite well too or it would probably fit inside the old case with a bit of suitable potting compound.

[rockinmark]

Would this be ok. mind you that looks a good idea chris.

[rockinmark]

Would anyone have a good copy of the data sheet on the back card that gives you the battery set up

[Herald1360]

Originally Posted by rockinmark

Would this be ok. mind you that looks a good idea chris.

Function wise it would be fine. It's your choice for appearance.

[davebms]

Originally Posted by rockinmark

Would anyone have a good copy of the data sheet on the back card that gives you the battery set up

hello all,, there is a very bad photo on the net
LT 2 VOLT GB -4.5 HT 120

dave

[Cobaltblue]

there are two GB taps -4.5 and -9V the -4.5V goes to the output valve grid Via the audio auto-transformer and the -9V goes to the front end gain control via the band switch.

I have a 483 but not sure where it is and how accessible.

Cheers

Mike T

[rockinmark]

I have to work out all the voltages yet and work out all the paper capacitors and valves. I have had to paint strip the varnish which I believe was put on like some sort of film the wood is a cheap ply with no grain, I have had to hand paint the wood which I'm pleased with my first time at this. I have checked the resistors and they are almost correct, all the cables are hard and need replacing

Mark

[Cobaltblue]

These cabinets are white wood.

The Burr Walnut pattern is added by a photographic process.

If you strip the finish you will end up with white wood.

Eventually I am going to have a go at the photographic process but its way down my priorities at the moment.

These looked great when they were new but its a really cheap cabinet.

Personally I like the 48 and 58 series sets the big oversize dials appeal to me.

Cheers

Mike T

[Sideband]

Originally Posted by rockinmark

Hi all trying to find out what I replace this capacitor with c33. It is huge says its 2 mfd. Why is it so big, I know the old capacitors are much bigger but I have never seen a paper capacitor that big

Mark

I have a Bush BA91 with an HT decoupler of 2uF just like that. I replaced it with a 2.2uF polyester rated at 250V. It will easily fit inside the original but I haven't done that yet.

Originally Posted by rockinmark

Why is it so big, I know the old capacitors are much bigger but I have never seen a paper capacitor that big

It's big because that was the technology of the time. You have presumably not seen inside a 1950's TV with an original boost capacitor still fitted. some of them were 1.5uF at 600V.....now they WERE big!

[rockinmark]

Yeah mike t that's what I ended with white wood but I got gel stains and painted the effect back on then varnished over that when dry well I'm happy with how it looks I couldn't leave it as it was to bad

[Nickthedentist]

Incredible work, Mark, brilliant result.

[rockinmark]

Thank you nick. I am just ordering the capacitors that I will need. I can order most of the capacitors apart from
c7 = 0.25uf
C31 = 0.05uf
Is there a equivalent to these in axial

[Cobaltblue]

C7 0.22uf C31 0.047 Are the modern equivalents

Cheers

Mike T

[rockinmark]

Thanks mike

[rockinmark]

I was looking at replacing the wires and have noticed the they are not multi strand wire but a single thick gauge wire the shielding is all brittle and falling off what would be best to do with this

There is a .0005mfd maca capacitor broken that goes to the aerial socket what should I use for that one

[HamishBoxer]

Use a modern silicon of the correct thickness multi strand or not if it looks ok.

[Herald1360]

Originally Posted by rockinmark

I was looking at replacing the wires and have noticed the they are not multi strand wire but a single thick gauge wire the shielding is all brittle and falling off what would be best to do with this



You could try unsoldering one end and slipping some silicone rubber sleeving over any that actually need to be insulated. Air is a pretty good insulator for rigid wires that are no tlikely to touch anything else of their own accord.


There is a .0005mfd maca capacitor broken that goes to the aerial socket what should I use for that one


A modern 470pF silver mica, ceramic or polystyrene type would be fine functionally. You may be able with a bit of judicious scraping with a scalpel or similar to expose enough of the old termination to solder a piece of tinned copper wire in place of the original leadout. Quite possibly a wanted request might turn something more in period up- the part in question isn't particularly rare.

Hope this helps....