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Old 13th Nov 2018, 6:24 pm   #1
Boater Sam
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Default BVWS Golborne demanding restorations.

Following the unsuccessful 'not buying any more sets' day last weekend.
I ended up not selling any of the sets I took to the bring and buy, but was given a Cossor 501, the one with the cream trim that usually shrinks and falls off, and could not refuse to steal a McMichael 137 as I was leaving.

Time is running out for restorations this year, we will be off to warmer climes very soon, so I limited myself to a quick inspection of both these radios this week.

The Cossor is a common set, I have 8 of the range, 500, 501, 520 etc.
This one is dirty, scruffy with a knob missing, frame aerial unravelling, glass falling out.
But its surprisingly good when a close look is taken. The dial glass is undamaged and has very clear printing. The card back / bottom is good as is the bakelite cabinet. Even the cream trim is good and still secure.
There appears to be no repairs other than a very burnt Mullard EL41 output valve replacing the Cossor original. This has the less common valve line up of Cossor B8A bottles rather than the B8G or Octals
Popping the chassis out, easy, the 3 remaining knobs came off easily, 2 screws, unplug the speaker and its out. Recovered the glass, 2 of the rubber corner retainers have turned to coal and broken off.
Removing the dead insects and some of the dust made the case and chassis a bit more pleasant to handle.
A quick run round with the meter revealed continuity of the transformers, no short circuits, so on with the lamp limiter. Rewarded with working dial lights, no bangs, and a glow from the valves. Going up to full power enabled stations to be tuned once an aerial was plugged in. Very satisfied that the set is worth restoring, switch off before any leaky capacitors caused any unforgivable damage.
Put it all back together and away till next year, finding space for a small set was fairly easy. Not so for the next one, the 137.

Moving on, next is the McMichael 137, like the 135 but with the rising dial as the lid opens. This one rises too far, the securing strap is detached probably due to someone fiddling trying to refit the demounted cord drive, that will be fun later. Unfortunately that has resulted in the wheel that should run on the metal slip scoring the inside of the lid a bit.

Removed the back, setting it aside with a quick pva repair to a delaminating bit of the ply, and inspected the works.
All correct valves present, plenty of dust and fluff. The rubber wiring is in fair condition, plenty of it too as this is one of the sets with a main chassis and a separate mains transformer and rectifier bolted to the base whilst the chassis is hung below the top board with 4 bolts through the base. Not simple to disassemble.
No obvious repairs or phantom twiddler horrors.
Feeling brave, aerial in and onto the lamp limiter. No drama, so up to power and wonderful, medium wave stations tune in without any whistles, sound is really good with that matched pair of speakers.
Long wave is totally deaf. The light in the lid needed the terminals cleaning before it would work. No smoke or crackles, a winner! The chassis is not earthed and the metalwork is giving me tingles, hope that this is not due to a breakdown to the screen in the mains transformer, I find out when I earth the chassis with a new 3 core mains lead. Shame really as the original cotton covered 2 core lead is in good condition.

As to go any further with this model involves lifting out the whole top and chassis in one I called it a day. Now to move a load of sets to make room for what is a big set. No stand with this one though, I may fit a set of turned legs instead. The cabinet has a few scratches and dry veneer feeling rough but should clean up well, its the mahogany version, not walnut.

So a very happy pair to sort out next year, along with maybe 40 other restorations as well!
I will really have to move some along to make room, there are now 9 sets living on the workbench, leaves no room to work.

Sam.

Last edited by Boater Sam; 13th Nov 2018 at 6:46 pm. Reason: Additional
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Old 14th Nov 2018, 10:44 am   #2
MurphyNut
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Default Re: BVWS Golborne demanding restorations.

Talking of the Cossor 501, I'm on the lookout for one if these, but the version with moulded edge rather than the horrible plastic trim one that in my mind spoils and cheapens the look of the set.
I'm always amazed at the size of the speaker in these sets, it seems like they put in the largest one they could.
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Old 14th Nov 2018, 11:16 am   #3
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Default Re: BVWS Golborne demanding restorations.

Hi Clive the moulded version is a 494

Cheers

Mike T
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Old 14th Nov 2018, 11:34 am   #4
Boater Sam
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Default Re: BVWS Golborne demanding restorations.

Yes, Mike, 494 is a one piece moulded case and will have the 7v series B8G valves or if you are lucky a 6V6 output valve.
I don't think the 501 looks that bad providing the trim has not shrunk and come loose or even fallen off. Its held with push on claw clips on thin pins moulded in the trim. These snap off easily.
There are some odd variations of this chassis, the "Melody Maker" went through a few incarnations.

I may have one, Clive, I'll have a look.

Sam.

Last edited by Boater Sam; 14th Nov 2018 at 11:39 am. Reason: added
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Old 14th Nov 2018, 3:40 pm   #5
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Default Re: BVWS Golborne demanding restorations.

Quote:
Originally Posted by Cobaltblue View Post
Hi Clive the moulded version is a 494
That's the one, thanks for that Mike.
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Old 14th Nov 2018, 4:48 pm   #6
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Default Re: BVWS Golborne demanding restorations.

I have two McMichael 135s and they are really good sets. Although they are 4 + 1 onod the 4 is just a double diode so I suppose they are strictly a short superhet. I think that the 137 may be a "full" superhet. Unfortunately the mains transformer in one of them needs replacing and I am thinking of stealing one from a PYE set of similar vintage
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Old 14th Nov 2018, 5:41 pm   #7
Boater Sam
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Default Re: BVWS Golborne demanding restorations.

Quote:
Originally Posted by MurphyNut View Post
Talking of the Cossor 501, I'm on the lookout for one if these, but the version with moulded edge rather than the horrible plastic trim one that in my mind spoils and cheapens the look of the set.
I'm always amazed at the size of the speaker in these sets, it seems like they put in the largest one they could.
Clive, I have found a 494 if you are interested. Its in good order apart from the IF transformers being missing, probably because these are the ones that drop their cores like DAC90As. I can find a better pair from an Ekco that could be fitted.
I'll send you a PM.

Sam.
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Old 15th Nov 2018, 9:54 pm   #8
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Default Re: BVWS Golborne demanding restorations.

Hi Sam, I've had a couple of McM 137 one AC only and the other AC/DC but traded them on - they do take up a lot of space! The overhead lamp arrangement never works well for long. Even after a dose of emery paper on the contacts it will start flickering again after a while. If you have to re-thread the tuning cord you are in for a treat. Open up the swear box. It is not quite as bad as some Philips arrangements though. As you say, the whole top board comes up and out bringing the chassis with it. On my AC unit the mains transformer was mounted on the baseboard but some I think are on the chassis. Mine being on the baseboard, I had to label all the wires from about a 20-terminal screw connector strip before disconnecting them as the cotton insulation colours had faded and it was easy to cross-connect by mistake. Also be careful lifting out the chassis because there is an insulated pillar with the top cap contact wire I think for the AC/TH1. It is easy for this to catch on the edge of the cabinet and snap off as it only a thin brass threaded rod inside (yes, mine did just that). Same can happen if you overtighten the nuts at the top and bottom. Deafness on LW apart from the obvious mucky wavechange contacts check the series choke L1 for continuity (Trader Sheet #710 refers). I think on mine I had to change the LW tracker C10 but there are some trimmers on the Aerial coils you can try to peak first. Have fun in the sun. Cheers, Jerry
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