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Music Magnet 4 AC Version

 
freya
(@freya)
Noble V-Ratter Registered

Was presented with a fine example of Music Magnet Four a while ago, and have started to look through it but it requires a couple of 650ohm grid leak style resistors. Any suggestions on these would be welcome as i have only ever seen much greater values. These are used for cathode bypass. see circuit.

ac

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Topic starter Posted : 25/02/2021 6:48 pm
freya
(@freya)
Noble V-Ratter Registered

So another question, what does everyone else do with these capacitors. Can they be opened neatly for re stuffing ? It is very evidently electrically leaky.

20210226 111724

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Topic starter Posted : 26/02/2021 11:24 am
Nuvistor
(@nuvistor)
Famed V-Ratter Registered

@freya

I have not seen one of these radios or that type of capacitor, please could you post photos of the radio.

Frank

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Posted : 26/02/2021 12:30 pm
freya
(@freya)
Noble V-Ratter Registered
570214918 o
alternative 3

 It seems to be very rare, they were a kit offered as an upgrade for the 2 volt battery version or fully built which this one appears to be.

Music Magnet 7b

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Topic starter Posted : 26/02/2021 12:50 pm
Nuvistor liked
Lloyd
(@lloyd)
Noble V-Ratter Registered

That capacitor looks similar to ones used in the R1155 radio, does it have a rubber bung at the top end? if so I just pulled it out on those, removed the innards and replaced with a new cap, cut a circle of thin card and stuffed it into the end where the rubber bung had been, then used 2 part epoxy (Devcon 5 minute, Araldite may work too) with a tiny bit of black paint in it to fill the end, complete with original solder tag.

Regards,

Lloyd

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Posted : 26/02/2021 2:48 pm
freya
(@freya)
Noble V-Ratter Registered

The capacitor is open at last, what a work of art. Must have taken serious time to make each one.

It involved grinding back the female threaded brass end,  heated the opposite end of the brass can with a heat gun until the solder is removed from the join, the end can be depressed inside (there is an actual spring !) revealing a slight lip on the can. Remove the lip diameter slightly and the innards can be pushed out. The female threaded end is a 5mm brass rod almost the entire length of the capacitor and actually acts as the former for the dielectric paper.

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Topic starter Posted : 28/02/2021 4:55 pm