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Old 22nd Jul 2019, 9:15 am   #1
Courtney Louise
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Default Cossor 934A - One owner from new...

I will start a separate thread for this Cossor but this is the internal condition untouched.
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Last edited by AC/HL; 22nd Jul 2019 at 3:25 pm. Reason: Thread split
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Old 22nd Jul 2019, 9:19 am   #2
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Default Cossor 934A - One owner from new...

OK So this is going to be the thread for the Cossor. Same story for this one, one owner from new, used until faulty I assume and then stored away and replaced with the KB.

This one has had V1 removed and has a 13 channel tuner neatly fitted to the side of the cabinet. and going through the RF chassis adjacent to the socket of the missing valve.

This one Has a full compliment of original Cossor valves. and after firing them all through the MiniMite valve tester I have shows a couple that are dead short and one that has zero emission.

So first task is to replace those three.

Even though both sets are full of waxies, none have melted out everywhere and there is little to no sign of any electrical distress or repair.

Mains dropper on this one too is lovely and clean, maybe they weren't used all that often?

I haven't cleaned either yet.
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Old 23rd Jul 2019, 10:37 pm   #3
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Default Re: Cossor 934A - One owner from new...

That looks in very good condition. It must have been stored in a reasonably dry location as there doesn't appear to be any sign of damp or corrosion (good news for the lopt, chokes and other such elements). How's the cabinet looking?
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Old 24th Jul 2019, 8:03 am   #4
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Default Re: Cossor 934A - One owner from new...

The LOPTs on the 930 series were a weak point, so much so that Radiospares supplied a replacement transformer for them.

It should be OK but would suggest you pass a current through the overwind for a few days before powering up. Good luck with it. John.
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Old 24th Jul 2019, 8:36 am   #5
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Default Re: Cossor 934A - One owner from new...

Must have been very reliable and ran till the end.
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Old 24th Jul 2019, 8:43 am   #6
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Default Re: Cossor 934A - One owner from new...

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Must have been very reliable and ran till the end.
Surely it would do?
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Old 24th Jul 2019, 9:03 am   #7
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Default Re: Cossor 934A - One owner from new...

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Must have been very reliable and ran till the end.
Surely it would do?
My Ferguson didn't!
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Old 24th Jul 2019, 12:13 pm   #8
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Default Re: Cossor 934A - One owner from new...

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Quote:
Originally Posted by stevehertz View Post
Quote:
Originally Posted by HamishBoxer View Post
Must have been very reliable and ran till the end.
Surely it would do?
My Ferguson didn't!
It failed before the end?! I thought the two coincided myself..
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Old 24th Jul 2019, 1:51 pm   #9
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Default Re: Cossor 934A - One owner from new...

Quote:
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The LOPTs on the 930 series were a weak point, so much so that Radiospares supplied a replacement transformer for them.
Hi Courtney,
I might have one of these NIB. It's at my parents' place (I'll be there mid August), but I did take a reference photo of the box which I will check out when I get back from work.
If you do find that you need it then send me a PM.

Cheers
Andy
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Old 24th Jul 2019, 5:43 pm   #10
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Default Re: Cossor 934A - One owner from new...

Quote:
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Quote:
Originally Posted by Brigham View Post
Quote:
Originally Posted by stevehertz View Post

Surely it would do?
My Ferguson didn't!
It failed before the end?! I thought the two coincided myself..
It failed three days before the end.

Fortunately, I had a PYE CTM 17 (The Continental- a childhood favourite) to see the era out...
...and back in again, twenty years later!
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Old 24th Jul 2019, 6:39 pm   #11
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Default Re: Cossor 934A - One owner from new...

I think the RS code for the Cossor transformer was LOPT 106. The Ferguson 306T was LOPT 108. J.
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Old 24th Jul 2019, 8:30 pm   #12
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Default Re: Cossor 934A - One owner from new...

Hi Courtney,
the box says it suits several Cossor sets including the 934. No mention of the 934A though, I wonder what the difference is?

Let me know if it is required.

Cheers
Andy
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Old 24th Jul 2019, 8:43 pm   #13
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Default Re: Cossor 934A - One owner from new...

Looking through some old RS catalogues I found a rather poor copy of the Mar/Apr, 1963 issue and on page 33, the transformers John mentioned are indeed listed. Please find attached a PDF file of the page including prices.
Regards Stan
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Old 25th Jul 2019, 1:58 am   #14
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Default Re: Cossor 934A - One owner from new...

Hi Andy,

That is indeed the right one. I don't know if I need it yet but please keep hold of it in case I do. I will shoot you a PM.

Thank you

C
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Old 25th Jul 2019, 8:59 am   #15
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Default Re: Cossor 934A - One owner from new...

Can I have 6 X LOPT 108 please at 39/6d. Please forward COD and I will pay the postman.
How easy it was! John.
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Old 25th Jul 2019, 9:07 am   #16
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Default Re: Cossor 934A - One owner from new...

How right you are John those were the days, anyway hopefully it will not be needed, but if it is then at least one has been found.
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Old 26th Jul 2019, 4:40 pm   #17
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Default Re: Cossor 934A - One owner from new...

So after getting a complete set of tested valves and noticing the cap across the mains has been previously changed I applied some power slowly.

Good parts.

We have all heaters,
We have sound,
We have frame buzz
We have Line Whistle.

Bad parts.

No screen illumination at all, not even when changing tuner channel, no collapsing frame or even a dot when turning off.

Still after a couple of suitable knobs if anyone has any please.

C
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Old 26th Jul 2019, 5:06 pm   #18
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Default Re: Cossor 934A - One owner from new...

It's quite a while since I had my head in the back of a CRT TV, is the EHT rectifier lit?
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Old 27th Jul 2019, 12:37 am   #19
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Default Re: Cossor 934A - One owner from new...

Good question as it's in a huge metal box that needs the chassis removed to get into
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Old 27th Jul 2019, 8:20 am   #20
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Default Re: Cossor 934A - One owner from new...

Before you go any further I would replace the line coupling capacitor C52 .01uf, the boost capacitor C56 .5uf and the CRT A1 decoupling capacitor C55 .1uf. [Newnes circuit references] This should liven up the line output stage and you can then carry out normal fault finding. John.
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