Cossor Melody Maker 234 - UK Vintage Radio Repair and Restoration Discussion Forum

Radio_Dave · 23rd Apr 2011, 12:42 pm

Hi,

My latest project is a Cossor Melody Maker 234. I believe everything is correct and present but at sometime in its past the wiring has been severely messed around with. I do have a basic circuit diagram, from Paul's CD and I shouldn't have any trouble reconnecting everything but what I would like to know is how the wires lay and what they are made from, colours, etc. Obviously, a few pictures of original examples will "speak a thousand words", as they say

.

Secondly, I've put a circle around what looks like a MES bulb holder. There's nothing showing a lamp on my circuit diagram, so what is it for?

Lastly (for now?), the second picture shows a knob on the left hand side of the cabinet. I'm sure it's not correct, can anybody show me a photo of how it should look?

TIA
David

Cobaltblue · 23rd Apr 2011, 1:02 pm

Hi Dave the lamp is a "fuse bulb". Very common in battery sets Cossor were fitting them well into the 30's. I will send some pictures of a 234 if I can find any of them!. I know where they should be........

Have fun

Mike T

Radio_Dave · 23rd Apr 2011, 1:16 pm

Thanks for the reply Mike. I guess these "fuse bulbs" are unobtainable now?

David

Cobaltblue · 23rd Apr 2011, 1:29 pm

Hi Dave in reality they are just ordiary bulbs All my Cossor data is at my other place but 150mA 3.5V seems to ring a bell (just like a DAC90A). Its unlikely to be a problem if you use a 200mA bulb.

Have fun Mike T

JoshWard · 23rd Apr 2011, 1:45 pm

I would have thought the wiring in one of these would be similar to other early sets with solid core conductor and perfect right angles when going round components?

Could be wrong of course but it would look very nice if you did it!

Josh.

23rd Apr 2011, 2:41 pm

I rewired mine using the cores out of 1mm twin and earth, now they have changed the colours so you may have to put up with brown/blue or get some three and earth which I think has a black core.

Here is my story... https://www.vintage-radio.net/forum/...ght=cossor+234

Herald1360 had mine with a copy of the original construction instructions, you might get a copy from him.

23rd Apr 2011, 2:46 pm

Oh, and any low current bulb will do for the fuse, it's in the HT- line I think.

Radio_Dave · 23rd Apr 2011, 2:56 pm

Thanks for the replies

. I like the twin and earth idea, I should have some in the garage! I'll also send a PM to Herald1360

Best Regards
David

AC/HL · 23rd Apr 2011, 8:44 pm

Dave,
Picture of the aerial trimmer knob.
It has a little moulded pointer just visible to the left.

That rusty patch should have a metal holder for the grid bias battery, and the screened lead coming out of the right hand coil goes to the top cap of the adjacent valve.

Apart from the blue colour, the wiring looks more or less right.
Regards, Bill

Radio_Dave · 24th Apr 2011, 9:35 am

Thanks for the help Bill

Regards
David

Ed_Dinning · 24th Apr 2011, 9:30 pm

Hi Dave, I think I have a copy of the original instruction leaflet for these sets.
If you get stuck PM me your e-mail and I'll try and send you a scan. It run to several A4 pages and details wire lengths etc.
The grid leak may well have gone high in value and the paper cap will be leaky, but generally these sets work well. The main other problems are associated with poor screwed connections.
60mA lamps (any voltage) work well for the fusebulbs.

Ed

Radio_Dave · 24th Apr 2011, 10:03 pm

Hi Ed, Thanks for the offer. Another forum member has already, kindly, offered to scan me the construction details, but if anything goes wrong I'll send you a PM

.

I haven't checked the caps for leakage yet, but their values measure well within tolerance, as do the resistors. Actually all the components are in remarkably good condition. It will be nice if all I have to do is hook everything up together again.

Regards
David

23rd Apr 2011, 12:42 pm	#1
Radio_Dave Nonode Join Date: Jun 2004 Location: Norwich, Norfolk, UK. Posts: 2,543	Cossor Melody Maker 234 Hi, My latest project is a Cossor Melody Maker 234. I believe everything is correct and present but at sometime in its past the wiring has been severely messed around with. I do have a basic circuit diagram, from Paul's CD and I shouldn't have any trouble reconnecting everything but what I would like to know is how the wires lay and what they are made from, colours, etc. Obviously, a few pictures of original examples will "speak a thousand words", as they say. Secondly, I've put a circle around what looks like a MES bulb holder. There's nothing showing a lamp on my circuit diagram, so what is it for? Lastly (for now?), the second picture shows a knob on the left hand side of the cabinet. I'm sure it's not correct, can anybody show me a photo of how it should look? TIA David Attached Thumbnails

23rd Apr 2011, 1:02 pm	#2
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 6,880	Re: Cossor Melody Maker 234 Hi Dave the lamp is a "fuse bulb". Very common in battery sets Cossor were fitting them well into the 30's. I will send some pictures of a 234 if I can find any of them!. I know where they should be........ Have fun Mike T

23rd Apr 2011, 1:16 pm	#3
Radio_Dave Nonode Join Date: Jun 2004 Location: Norwich, Norfolk, UK. Posts: 2,543	Re: Cossor Melody Maker 234 Thanks for the reply Mike. I guess these "fuse bulbs" are unobtainable now? David

23rd Apr 2011, 1:29 pm	#4
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 6,880	Re: Cossor Melody Maker 234 Hi Dave in reality they are just ordiary bulbs All my Cossor data is at my other place but 150mA 3.5V seems to ring a bell (just like a DAC90A). Its unlikely to be a problem if you use a 200mA bulb. Have fun Mike T __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk Last edited by Cobaltblue; 23rd Apr 2011 at 1:31 pm. Reason: Forgot the all important A

23rd Apr 2011, 1:45 pm	#5
JoshWard Octode Join Date: Dec 2005 Location: Near Stowmarket, Suffolk, UK. Posts: 1,962	Re: Cossor Melody Maker 234 I would have thought the wiring in one of these would be similar to other early sets with solid core conductor and perfect right angles when going round components? Could be wrong of course but it would look very nice if you did it! Josh.

23rd Apr 2011, 2:41 pm	#6
Guest Guest Posts: n/a	Re: Cossor Melody Maker 234 I rewired mine using the cores out of 1mm twin and earth, now they have changed the colours so you may have to put up with brown/blue or get some three and earth which I think has a black core. Here is my story... https://www.vintage-radio.net/forum/...ght=cossor+234 Herald1360 had mine with a copy of the original construction instructions, you might get a copy from him.

23rd Apr 2011, 2:46 pm	#7
Guest Guest Posts: n/a	Re: Cossor Melody Maker 234 Oh, and any low current bulb will do for the fuse, it's in the HT- line I think.

23rd Apr 2011, 2:56 pm	#8
Radio_Dave Nonode Join Date: Jun 2004 Location: Norwich, Norfolk, UK. Posts: 2,543	Re: Cossor Melody Maker 234 Thanks for the replies. I like the twin and earth idea, I should have some in the garage! I'll also send a PM to Herald1360 Best Regards David

23rd Apr 2011, 8:44 pm	#9
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,643	Re: Cossor Melody Maker 234 Dave, Picture of the aerial trimmer knob. It has a little moulded pointer just visible to the left. That rusty patch should have a metal holder for the grid bias battery, and the screened lead coming out of the right hand coil goes to the top cap of the adjacent valve. Apart from the blue colour, the wiring looks more or less right. Regards, Bill Attached Thumbnails Last edited by AC/HL; 23rd Apr 2011 at 8:49 pm. Reason: Added info

24th Apr 2011, 9:35 am	#10
Radio_Dave Nonode Join Date: Jun 2004 Location: Norwich, Norfolk, UK. Posts: 2,543	Re: Cossor Melody Maker 234 Thanks for the help Bill Regards David

24th Apr 2011, 9:30 pm	#11
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,196	Re: Cossor Melody Maker 234 Hi Dave, I think I have a copy of the original instruction leaflet for these sets. If you get stuck PM me your e-mail and I'll try and send you a scan. It run to several A4 pages and details wire lengths etc. The grid leak may well have gone high in value and the paper cap will be leaky, but generally these sets work well. The main other problems are associated with poor screwed connections. 60mA lamps (any voltage) work well for the fusebulbs. Ed

24th Apr 2011, 10:03 pm	#12
Radio_Dave Nonode Join Date: Jun 2004 Location: Norwich, Norfolk, UK. Posts: 2,543	Re: Cossor Melody Maker 234 Hi Ed, Thanks for the offer. Another forum member has already, kindly, offered to scan me the construction details, but if anything goes wrong I'll send you a PM. I haven't checked the caps for leakage yet, but their values measure well within tolerance, as do the resistors. Actually all the components are in remarkably good condition. It will be nice if all I have to do is hook everything up together again. Regards David