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Old 23rd Nov 2017, 2:07 pm   #1
Neutrino
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Default Cossor 501 Melody Maker Working Again

The Cossor 501 Melody Maker was purchased at a British Vintage Wireless & Television Museum garden party. It is the youngest and probably the easiest to get going wireless in my collection.

The reservoir and smoothing capacitor was replaced with a new one from BVWS because the original had a bulge. The original negative connection was through the can and clamp. The new capacitor has an insulated can and a negative terminal which I connected to a wire soldered to the head of one of the fixing screws because I did not have a solder tag washer. The drive chord and that capacitor (coupling the anode of the triode to the audio output valve) were replaced. The resistors were more or less within tolerance. The cabinet was wiped and the dial glass cleaned to some extent, while trying to avoid the lettering.

The snap fastener for voltage adjustment on the mains transformer was loose and no matter how many times I took it off and tightened it with pliers it was loose again after pushing it back on. Eventually I soldered a wire link across it. The chassis is earthed through the mains lead and the live is switched.

The set was tried first on the series lamp limiter. It only needed a little Servisol Super 10 on the waveband switch. The voltages were close to those in the “Trader” Service Sheet. The set works very well with a good quality sound on long, medium and short wavelengths, even with an indoor aerial. The stations are in about the right place on the dial. No alignment was done.

The case is in good condition but the back is missing and the speaker grill could do with replacing but the biggest problem is that the gold plastic escutcheon has shrunk. I do not have a solution to this so I think I will leave it as it is for now and start on a Ferguson 207U.

David
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Old 25th Nov 2017, 2:17 pm   #2
HamishBoxer
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Default Re: Cossor 501 Melody Maker Working Again

Tidy job where I am sat.
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Old 1st Dec 2017, 10:14 am   #3
PaulR
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Default Re: Cossor 501 Melody Maker Working Again

Another one saved, well done. The wooden version was my first restoration. It is so satisfying to hear stations coming through for the first time. Judging by the number of these sets on Ebay Cossor must have done a roaring trade in them.
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Old 1st Dec 2017, 10:56 am   #4
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Default Re: Cossor 501 Melody Maker Working Again

With a lot of care and hot water you can get the plastic surround to fit again, but it then needs to be glued in.
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Old 1st Dec 2017, 1:51 pm   #5
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Default Re: Cossor 501 Melody Maker Working Again

Good job David nice description of a simple fix, no mass component changing or unnecessary stuffing. Not every ones view but I'm all for preservation not restoration.

John
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Old 1st Dec 2017, 10:58 pm   #6
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Default Re: Cossor 501 Melody Maker Working Again

I have an identical one which was one of the first sets which I bought which got me interested in vintage radio. It has the larger metal rim base valves which could be an earlier version. It has the same mains transformer with the coat popper voltage adjuster. Mine needed nothing doing to it to get it to work other than a good clean and polish. It does sound good. I think my version doesn't have the separate surround but looks like the cabinet and speaker surround were moulded in one piece and then the cream colour is painted on.
Christopher Capener
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Old 1st Dec 2017, 11:36 pm   #7
Cobaltblue
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Default Re: Cossor 501 Melody Maker Working Again

The sets with the solid Bakelite case without the additional Escutcheons are the otherwise near identical 494 and 494U

Cheers

Mike T.
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Old 2nd Dec 2017, 1:46 am   #8
Boater Sam
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Default Re: Cossor 501 Melody Maker Working Again

That was progress, the early one piece case on the 494 was fine, the later 501 separated.
I prefer the 500 & 520 woody ones, the flat top can be used for putting things on.
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Old 14th Dec 2017, 10:33 am   #9
MurphyNut
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Default Re: Cossor 501 Melody Maker Working Again

Nice job, one of these is on my want list, I've always thought they might sound good going by the generous sized speaker they contain.
They seen quite plentiful, but often let down by that plastic escutcheon, often shrunk or broken.
I have seen a version were it doesn't have the plastic escutcheon but this area made from the cabinet molding instead, I'm temped to track one of these down.
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Old 14th Dec 2017, 12:18 pm   #10
PaulR
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Default Re: Cossor 501 Melody Maker Working Again

Yes, the large speaker does make them sound good.

The SW coil was broken in mine so instead of attempting to repair it I abandoned SW and used the redundant switches to switch between the radio and the PU sockets to make it easier to use them. It now gets regular use in the kitchen as a radio and connected to a portable CD player.

I can never understand why so many manufacturers provided PU sockets but no easily accessible switch to use them.
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Old 14th Dec 2017, 1:44 pm   #11
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Default Re: Cossor 501 Melody Maker Working Again

Which SW coil do you mean - aerial or oscillator?

The SW osc coil is actually dead easy to rewind, it is on a grooved Bakelite former, guaranteeing the wire positioning and separation. Wire diameter is not massively critical either. Although, to be fair, if you do rewind you may wonder why you bothered as the SW performance is not startling.

I agree with Paul about no switch for the PU socket, this is really horrid! Radio breakthrough arises, and there's the distortion aspect also because of the diode connected nearly across the PU input!
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Old 14th Dec 2017, 2:16 pm   #12
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Default Re: Cossor 501 Melody Maker Working Again

It was the oscillator coil. I didn't think it was worth trying to rewind it as having a switch for the PU sockets is much more useful. If I ever bought another one I would be tempted to disable the SW intentionally to have a switched PU socket. Fortunately the SW switches don't affect anything else and so can be used for something else without affecting the rest of the set.
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Old 31st Dec 2017, 10:53 pm   #13
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Default Re: Cossor 501 Melody Maker Working Again

I had the reverse with my 494. Worked beautifully on SW, but very deaf on MW/LW and first 100 m of band spread across whole dial. I think that was the oscillator coil.
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