Cossor 3339 Oscillograph(Scope).

[peter_scott]

Here's the CRT Table. Sorry it's a bit difficult to fit on the scanner. I can supply missing info on request.

Peter

[WME_bill]

I am amazed at the speed of Peter_Scott's reply, and that he has the article I've been searching for. Sending him a PM. Many thanks.

Back to the Cossor 3339 and 339. I think a red herring has turned up somehow.
The 339 was a later war-time modification to the pre-war 3339. The war time version used 807 valves, on UX 5pin bases. The prewar one did not - I would expect 42SPT on British 7 pin (or Philips AL60/CV9 on B7 base as used in the Hartley 13A).
The STC 5B/254 and 5B/255 were I believe post war, on B8G bases, comparable with Loctal B8B. My Standard Telephones & Cables data sheet is dated 1961. While the STC sheet for 5B/250A (807) is dated 1945. .
In early 1950's, valves using B8B Loctal bases, the 7x7 style, were used in America, as they offered higher reliability, but never appeared much in UK.
The Cossor 1035 MarkIII, a very different machine from the MarkI/II, was I believe re-engineered to use 7x7 series valves for the American or Canadian market and sold as type 1036/1037 in mid 1950's.
I think you will find that apart from valve types (and lower performance), the 339 is the same as the 3339, and the changes will have been minimal, apart from the UX5 bases. They may even have used the stock of old chassis punched for B7 bases, and fitted a reducing plate for the UX5 base. Bill m0wpn

[David Simpson]

Peter & Bill, Many thanks for all the extra info. Shall now try & attach some pictures of the sorry scope. Should've done them at first last week, but my computer has decided its now incompatable with my wee Cannon camera.

Regards, David

[David Simpson]

Plus two more pictures. L/H one is of the useless replacement transfoormer fitted. And the r/h one is of the chassis underside, now that most of the horrible wiring has been removed. Regards, David

[WME_bill]

The bases in your pictures look very like B9G, as used by the EF50. So perhaps your previous owner was building a TV I.F. strip, for which the EF50 was the traditional valve.
The 1939 Pye 915 TV used the "Pye IF Strip" with 5 EF50 on 45 MHz. The performance was so good that it was taken immediately and used in the early Radar Sets. The EF50 had been developed by Philips to meet Pye specifications, and there was rather a flap when it was realised that almost the entire stock of valves and all the manufacturing plant and tooling was in Holland. The tale is that it was all removed and carried across the North Sea in May 1940 on a Dutch merchantmen as the enemy marched into Eindhoven. Bill

[David Simpson]

Right enough, Bill - those valve bases do look like B9G's rather than Loctals now that I've removed them & given them a good clean. Should've looked at them more closely & taken a pin count. I'd just wipped them out & dumped them in a box, with a view to fitting IO's again, plus a B4 & UX5's.
"Should've gone to SpeckSavers" as the TV ad says.
Sourcing a transformer is still top of my list, followed by the two missing correct double pots & their inner & outer cossor knobs.
To those Forum guys who have contacted me so far after raking through their shelves & boxes for spares - I'm really grateful.

Regards, David

[David Simpson]

Bill, Pity we dont share the flat at 221 Baker St. Although Id make a poor Watson to your Sherlock. Have now stripped the chassis completely, and lo & behold, pencilled on the underside is - - EF50,EF50, & EF54 alongside three former valve positions !
Now its time for cleaning, rubbing down, and re-spraying the chassis & the double mu-metal shield, and casing.

Regards, David

[woodchips]

Having sorted the CRTs for David, doing some more hunting around and found a small book called:

Mullard Radio & Television Receiver Servicing with Cathode Ray Oscillographs GM.3152 and GM.3155

No date but my dad has signed inside with his RAF number, so must have been bought whilst he was servicing the radar from 1940 to 1945, I would guess 1940. Does anyone know anything about this? I have searched and come up with nothing, not even the scope part numbers.

Also come across an advert from Cossor for the 3339 dated April 1939, and a circuit that must be for the 3339, even though in an envelope marked 339, using a 09J CRT with 41FP, MS-PEN, 42SPT, 44IU and 225DU valves. Cut out of what looks like a book, just read Maintenance and Service on the reverse.

Bob

[WME_bill]

for "woodchips". Philips GM3152. The manual I have is dated 1946, though model introduced I understand in 1941. The GM3156 was introduced in 1947 with side contact valves, and with International Octal valves as Mullard E800 in 1948. The GM3155 was presumably about that time also. So this suggests your dates are about correct.
I have been looking for information upon the Cossor 3339. I suspect your diagram is exactly what I want. The valve types and the date correspond with what I expect. Is there any chance you could post a copy of the diagram please. Or send me a Private Message to arrange emai contact.
for "David Simpson". The hunt for this ruthless criminal mastermind is getting more interesting every day. Bill m0wpn

[woodchips]

The photograph (scanner doesn't work) and pdf files are too large for the forum. I have emailed the pdf to David to see if quality is ok. Bob

[David Simpson]

Probably best to obtain as an email attachment. All the latest 4 sheets come to about 9.6Megs, and have printed off really good considering the faded state they were in.
Many thanks to Bob, David

[David Simpson]

Folks, "Before" status shown in earlier pics. Have now taken the first of the "After" pics.

Regards, David

[AC/HL]

David
I knew I had a manual, but after a house move I have only just re-discovered it.
I'll never need it, so if you PM me with your address Ill pop it in the post. The valve line-up is as Bob quoted, so it must be the same vintage, although I can't find a date anywhere.
Perhaps you could forward it or a copy to Bill when you have finished with it. The manual will explain the confusion over the CRT too, it depended on use.
Regards, Bill

[David Simpson]

Many thanks to Bill for posting me an original Cossor 3339 Instruction Manual. I'll make a scanned copy or two, for other 3339 enthusiasts, as its more specific than the 339 Manual available on the internet in pdf format.

Regards, David

[David Simpson]

Folks, Thought I'd post a couple of pics showing progress of re-build. Many thanks again to :- ED, Bob, Leon, Bill, Brian, Andy, Sean, Peter(and anyone who my dim memory has forgotten) - for donating parts & paperwork, and for helpful advice.

Regards, David

[Alf Fisher]

Hi David and all,
This thread seems to have gone a bit quiet lately so for my twopennyworth, I have a 3339 in the museum and its Y plate output valves are 42SPT which are big valves (fatter than an 807) but have 4 volt heaters and a British 7 pin base. Not sure if you are planning a rebuild of this scope to make it a 339 using 6.3 volts octal based valves.

Regards,
Alf

[David Simpson]

Alf, I mentioned some time back that the poor beast had been extensively altered & attempted to be made into a primitive TV. None of the original valves or their valvebases remained. (See previous pics from a few months back).
I've re-affixed all valvebases with two paxolin strips in the 339 layout, as these were the valves kindly donated by Forum guys and a local vintage enthusiast. I guess eventually this will look a 3339 externally, but with mainly 339 circuitry internally.
I'm still stuck for Pots -R43, R2/R4/Trig Sw.,R18/R25 & the 4 wafer Ampl. Sw., plus knobs. As these were all missing from the scope when I aquired it. I'm hoping the con. tandem pots were used in other Cossor scopes & therefore better the chances of folk finding one or two in a gashbox somewhere.

Regards, David

[See_Mos]

I know this is an old thread but I was just surfing and looking for some of the old stuff that I used to own.

I had a 339 with the long persistance tube, it had a lovely violed trace!

It had 807's for the output and I am fairly sure that it had EF50's in the input stages

[David Simpson]

Bit of an update - Thanks to Mark the Mender & Rob Lines, my transport request regarding getting an old 339A up to the north of Scotland is now sorted. It'll be arriving in Morayshire at the end of the month.
This means that this cheapo ex Ebay purchase can be used as a donor for completing the rebuild of my original 3339. A fine winter project to look forward to.


Regards, David

[David Simpson]

Great day, today. Met up with Rob Lines & collected 339. Yes, a 339 not a 339A - which the orig seller described it. So being that bit older - should be more compatable for donating bits to the 3339. Possibly of military origin, going by the crows foot & 10C ref nos on the big capacitors,( one of which is seriously leaking oil). The 807's, the EHT Rect., and the other valves all look OK, as does the CRT. Everything grubby & dusty, and a bit of rust here & there. But what does one expect for a wartime scope.
Shall continue with the physical inspection, then carefully remove the valves & CRT. Although, thanks to Ed, I already have a spare mains T/F, the first thing I'll test is it's T/F. No phyical signs of arcing/tracking, or carbonization on the leads & tag-board, but you never know.
Have attached some pics.
Oh yes, the rear paxolin connection board has been modified to take a wee bulgin type 3 pin plug. The example above it is what my 3339 & 339A has.

Regards, David