Re: Old (presumed Dud) CRTs discovered - value?
 

Can I just say well done for saving these pieces; even down to the bunting, mannequins and misc. there will be a use. Glad to say it all seems rather steampunk-proof, particularly given the nanny state's nervousness about old CRT's.

Should anyone ever visit RAF Elvington (Yorks) I would be interested in their opinion on the mannequins and dioramas in the control tower (which I assume are still there..) Saying more would be giving the game away.

Dave

Re: Old (presumed Dud) CRTs discovered - value?
 

Just a quick update from my friend who has removed all the CRTs from the shop.

In addition to the CRM92 we have already seen, he has discovered three more CRM92, two CRM121 and one CRT with a broken neck and no identifying labels.

I'm hoping to get a look at them next week and a colleague at work who plays with vintage TVs may be able to lend me a CRT tester. I better check it can test these Triodes, I gather that not all testers can.

Regards,

SR

Re: Old (presumed Dud) CRTs discovered - value?
 

You are correct, most CRT testers cannot be used on a CRM92. I use either my Avo or Taylor valve testers to check these types.
A simple lead was made up from an octal valve base to connect to the tester to crocodile clips to the CRT pins, the results are quite accurate on the tubes I have tested so far.

If I remember correctly, an external PSU was used to supply the CRT heater.
It should draw 1.4 amps @2v.
:beer:
Mark

Re: Old (presumed Dud) CRTs discovered - value?
 

Just to mark my interest in one of the CRM92 if there's some life in it. This will be going into a Murphy v136 or my EKCO TS88.

One point of caution would be to take care of the tube base especially if it is loose.
Also to protect the tube from damage by storing it in a suitable box.

I read somewhere where a tube had imploded sending glass all over workshop damaging other tubes close by.

Mark.

Re: Old (presumed Dud) CRTs discovered - value?
 

I'll keep the forum updated. I hope to be collecting the remainder of this stash in the coming week then will see if I am able to test in any way. I like "space_charged's" test method but I can't lay my hands on an EHT supply.

Some test results would allow us to suggest a price and start a Parts Offered thread. The main purpose of this thread was to established that there is some interest, which there now is, so these CRTs shouldn't end up down the tip.

'radiomarktv' I'm happy to earmark one CRM92 for you if the Mods and fellow forum members are happy to allow this. I think further expressions of interest should wait until we've decided a price and put these up on the appropriate section.

I've seen a post here on a CRM92 that imploded in storage. I am treating this with a little more respect now. If testing, will probably go for croc clips rather than trying to wiggle an octal valve base on the end.

Regards,

SR.

Re: Old (presumed Dud) CRTs discovered - value?
 

Old post from Darius:
https://www.vintage-radio.net/forum/...ead.php?t=5505

Jac

Re: Old (presumed Dud) CRTs discovered - value?
 

I had a bit of company on my way back from car club last night.

Sadly two haven't been stored that well and the only non-Mazda CRT is a necked Cossor. It's been like that for a while and the model number label is too faded to read. The second pip on the bulb has been snapped too. I imagine this one is only good for the tip, but it does have an interesting looking base connector with 4 flat sockets. I could save that if that's of any use.

Only armed with my Maplin analogue multimeter, I've established that all the Mazda heaters are intact and cannot detect any shorts (on Hi Z ranges) between other base connections.

None of the serial numbers match those on the boxes and all boxes are marked with a cross, 'U/S' or 'No Good'.

Interesting to see two different box designs; some CRTs are face down on a pad of corrugated cardboard whilst others are face up suspended by the cone in a cardboard cradle. One box includes an Edison Swan guarantee card whilst another box was a nice surprise.....

The pictures that follow do not include the first CRM92 shown on this thread a couple of weeks ago.

SR

Re: Old (presumed Dud) CRTs discovered - value?
 

So here's the first CRM92A, serial number 42128

Re: Old (presumed Dud) CRTs discovered - value?
 

Another CRM92A, serial number Z50718.

Re: Old (presumed Dud) CRTs discovered - value?
 

Final CRM92A, serial number Z37560.

This seems to have a few blemishes in the phosphor in the form of small black dots. They definitely can't be felt on the tube face.

Re: Old (presumed Dud) CRTs discovered - value?
 

Then carefully, pulled out a CRM121A, serial number 13869/5.

This seems to have a single 'bubble' visible on the face.

Re: Old (presumed Dud) CRTs discovered - value?
 

Hi Stuart,
Could you hold on to the Cossor tube remains and not bin it, for interest I would like to see it.
As for the remainder it looks like they may never work but still should be kept if they are all dud.
Mark.

Re: Old (presumed Dud) CRTs discovered - value?
 

Then the last, another CRM121A, serial number 10117.

This one has a small blemish in the screen too, centre of frame in the last photo.

Re: Old (presumed Dud) CRTs discovered - value?
 

My HMV 1807 has a large bubble on the face and always thought this should of been rejected from manufacture. The tube does give a great picture, its a shame the 1807 had such a bad reputation for HMV.
Mark.

Re: Old (presumed Dud) CRTs discovered - value?
 

So that's all the CRTs done. The unboxed Mazda was actually lurking in this box, which somebody may also like to save (radio not included).

https://www.radiomuseum.org/r/master..._d120d_12.html

One CRM121A box was marked with £18.3s.2d. Would that have been the price, or just someone's random jottings on a a box that was close to hand?

Mark, I can certainly keep the remains of the Cossor and hand them over for inspection at NVCF, I won't want to be taking them home again! I know that you're also interested in one, maybe more of the Mazdas.

I'm not sure now if I can make any headway with further testing before NVCF. TV isn't my speciality.

Probably time to decide on a price and start an Offered post soon.

Regards,

SR

Re: Old (presumed Dud) CRTs discovered - value?
 

Seems probable. The nearest comparable reference to hand here is Ferranti's 1956 guide to valve and tube replacement, where 12" tubes are priced, inclusive of purchase tax, at £17.5s.4d or £18.6s.11d according to type. (Pre-tax prices were £12 and £12.15s. respectively).

Paul

Re: Old (presumed Dud) CRTs discovered - value?
 

The CRM92s look very much vacuumless, but I'm not absolutely sure about the (more desirable) CRM121s. Is it still available for £18-3s-2d (£18.16)? ;)

Re: Old (presumed Dud) CRTs discovered - value?
 

Probably a 10" 108K [post war]

A very good tube and used slightly modified under the EMI label in some 1807 receivers. It was given the EMI number 3/20. John.

Re: Old (presumed Dud) CRTs discovered - value?
 

Thanks for all your thoughts and comments so far.

I have had a few other PMs from interested parties so to keep everything fair and open, I hope that freya and Catkins won't object if I mention that here. After a discussion with my friend, I think it's time to offer these up for sale.

Keep your eyes peeled in the Offered section.