UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Television and Video

Notices

Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

Reply
 
Thread Tools
Old 5th Nov 2019, 3:30 pm   #1
TopTip
Triode
 
Join Date: Feb 2006
Location: New York, NY, USA
Posts: 16
Default Decca 121 projection TV

I bought this Decca 121 a while ago. It sat around until I was able to locate a fresh CRT to replace the burnt original. I finally found one (in the "Merry Christmas" bottle box), salvaged from a German SABA.

A few weekends ago I took the cabinet apart, cleaned out decades of cobwebs and dust. That is also when I discovered, unfortunately, that someone has helped himself to its flyback transformer at some point (upper left, above the projector mirror case). I do not even know how / where to look for one. I suspect there may have been more common sets that used the same transformer?

Until I find one, this 21" Sony LCD TV, which fits well, will have to do temporary duty. I will craft a new bezel to make it look more finished. The screen of the Sony is nearly black as it has a plastic film in the front. I am thinking of peeling it off and replacing it with a translucent white sheet. That will probably ruin the contrast but, again, may help with a more authentic look.
Attached Thumbnails
Click image for larger version

Name:	Parts.jpg
Views:	179
Size:	87.4 KB
ID:	193141   Click image for larger version

Name:	Sony.jpg
Views:	160
Size:	51.9 KB
ID:	193142  

Last edited by AC/HL; 12th Nov 2019 at 9:09 pm. Reason: Thread split
TopTip is offline   Reply With Quote
Old 5th Nov 2019, 8:12 pm   #2
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 6,890
Default Re: Spotted - ID needed please - console TV.. Decca??

The line output transformer is the cylinder can on the main chassis. The item missing is the 25kv ringing choke/EHT tripler assembly that is mounted in a sealed, oil filled, square can complete with EHT lead.
The unit was used with the optical unit in every British projection receiver. It is a Philips part. John.
Attached Thumbnails
Click image for larger version

Name:	Philips EHT unit..jpg
Views:	141
Size:	89.0 KB
ID:	193151  
Heatercathodeshort is online now   Reply With Quote
Old 5th Nov 2019, 9:28 pm   #3
TopTip
Triode
 
Join Date: Feb 2006
Location: New York, NY, USA
Posts: 16
Default Re: Spotted - ID needed please - console TV.. Decca??

So then in this TV, unlike later TVs, line out and EHT is not combined into one flyback unit? Does that mean that I can use any 25kV supply if I cannot find the original part?

Thank you
TopTip is offline   Reply With Quote
Old 8th Nov 2019, 10:47 am   #4
beery
Heptode
 
beery's Avatar
 
Join Date: Jun 2006
Location: Ware, Hertfordshire, UK.
Posts: 705
Default Re: Spotted - ID needed please - console TV.. Decca??

Yes, any 25KV source will do, however the anode connector would be hard to find on its own.
And yes, I do have a used spare which is untested, but I don't know how easily it can be shipped over as it is oil filled.
I will dig it out over Christmas and send you a PM.

Cheers
Andy
beery is offline   Reply With Quote
Old 8th Nov 2019, 12:16 pm   #5
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 6,890
Default Re: Spotted - ID needed please - console TV.. Decca??

When you get it together I would suggest that you leave the original Mullard MW6-2 in place. It will serve as a good test CRT until you get the chassis working correctly. One single line or frame collapse, even for a fraction of a second will burn the CRT face of your good CRT.
There are protection circuits that cut the CRT off in the event that such a fault occurs but you have to make sure these are working correctly!

From a historical point, these receivers were manufactured by the famous Plessey Co. at Ilford Essex as were all Decca television receivers until 1954/5. John.
Heatercathodeshort is online now   Reply With Quote
Old 8th Nov 2019, 11:34 pm   #6
TopTip
Triode
 
Join Date: Feb 2006
Location: New York, NY, USA
Posts: 16
Default Re: Spotted - ID needed please - console TV.. Decca??

Last night I was reading a Philips site and learned that the same MW6 projector CRTs were sold in the US as the Norelco Protelgram 3NP4. Amazingly, there was one on eBay. It was cheap enough that I bought it. I will see if at least its filament is good when it arrives. Then I will have a spare or one to share!
Attached Thumbnails
Click image for larger version

Name:	D9550910-E194-45ED-9660-A2750160F210.jpg
Views:	65
Size:	37.3 KB
ID:	193390  
TopTip is offline   Reply With Quote
Old 8th Nov 2019, 11:39 pm   #7
TopTip
Triode
 
Join Date: Feb 2006
Location: New York, NY, USA
Posts: 16
Default Re: Spotted - ID needed please - console TV.. Decca??

Quote:
Originally Posted by beery View Post
Yes, any 25KV source will do, however the anode connector would be hard to find on its own.
And yes, I do have a used spare which is untested, but I don't know how easily it can be shipped over as it is oil filled.
I will dig it out over Christmas and send you a PM.

Cheers
Andy
That would be amazing. I am in London reasonably often, I can probably arrange to pick it up somehow. I have been reading that to test it, I need 6.3 and 375 volts, the latter at 50mA.
TopTip is offline   Reply With Quote
Old 9th Nov 2019, 10:05 am   #8
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 6,890
Default Re: Spotted - ID needed please - console TV.. Decca??

Generally if the screen is a pure white similar to copy paper it will be OK. Tired examples have a light brown square where the picture has been and will give a dull picture. J.
Heatercathodeshort is online now   Reply With Quote
Old 11th Nov 2019, 5:08 am   #9
TopTip
Triode
 
Join Date: Feb 2006
Location: New York, NY, USA
Posts: 16
Default Re: Spotted - ID needed please - console TV.. Decca??

This seems to have some brown.
Attached Thumbnails
Click image for larger version

Name:	0C791825-F874-437F-95BC-B83EAC4AA290.jpeg
Views:	82
Size:	53.3 KB
ID:	193563  
TopTip is offline   Reply With Quote
Old 11th Nov 2019, 12:14 pm   #10
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 6,890
Default Re: Spotted - ID needed please - console TV.. Decca??

That looks OK to me. An aged tube will show a very pale yellow/brown rectangle in the area the picture is formed due to the intense electron beam at 25kv on a 2 1/2" tube.

Burn marks due to circuit faults are small black dots or imperfections that magnify into large blemishes when seen on the receiver screen. Make sure the tube face is clean. Your marks look like they are just dirty smears.
At least you can use this one for test but do not fit a good tube until you are sure everything is operating correctly. John.
Heatercathodeshort is online now   Reply With Quote
Old 12th Nov 2019, 1:23 am   #11
TopTip
Triode
 
Join Date: Feb 2006
Location: New York, NY, USA
Posts: 16
Default Re: Spotted - ID needed please - console TV.. Decca??

Looks like in the US they sold these as conversion kits for direct view TVs:

https://www.earlytelevision.org/pdf/ee_9-50.pdf

https://www.earlytelevision.org/pdf/duo-view.pdf
TopTip is offline   Reply With Quote
Old 12th Nov 2019, 11:09 am   #12
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 6,890
Default Re: Spotted - ID needed please - console TV.. Decca??

These conversion kits were widely advertised in 'Radio and Television News' during the mid to late 1940's. John.
PS Advert from R&TV News Sept 1948. This unit uses the 5" 5TP4. The MW6-2 or 3NP4 arrived just a little later. The American version appears to be the MW6-2 imported and renamed especially as it has the side contact base.
It may be possible to locate the EHT unit used on these models for your Decca. J.
Attached Thumbnails
Click image for larger version

Name:	PTV.jpg
Views:	38
Size:	78.4 KB
ID:	193611  

Last edited by Heatercathodeshort; 12th Nov 2019 at 11:35 am.
Heatercathodeshort is online now   Reply With Quote
Old 12th Nov 2019, 5:10 pm   #13
TopTip
Triode
 
Join Date: Feb 2006
Location: New York, NY, USA
Posts: 16
Default Re: Spotted - ID needed please - console TV.. Decca??

Yes, I am thinking I need an original unit — someone said, in the Decca, it is part of the main circuit also. I have not checked to see if that is the case yet.

In the meantime, I routed a channel in the plywood of the top of the TV, so it can accommodate the Sony panel. I figure rejuvenating the Decca chassis will be a long term project. This will allow it to be used in the meantime. I can always refill the channel but it also does not in any way interfere with how the Decca screen mounts.
Attached Thumbnails
Click image for larger version

Name:	B8A14C00-8923-43DA-ACAE-00198DDAF451.jpg
Views:	44
Size:	57.1 KB
ID:	193624  
TopTip is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 11:49 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.