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 24th Oct 2019, 6:01 pm   #1
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,946
Default Anyone ID this Loptx ?

On the can thereís a date , 14 Dec 1988? This is maybe an inventory date instead of a mfr date.

I havenít seen one with this appearance before ...

There is an auxiliary transformer with the blue winding being an overwound primary: underneath is a ferrite core with enamelled wire as a secondary. Iím not sure what this served ?

Thanks folks
Attached Thumbnails
Click image for larger version

Name:	DBC4320D-E6F4-4885-80F7-1BBDDA3D2095.jpg
Views:	234
Size:	44.9 KB
ID:	192388   Click image for larger version

Name:	EE65418A-B873-4B82-A36E-2ADC61B3DCB4.jpg
Views:	180
Size:	40.5 KB
ID:	192389   Click image for larger version

Name:	D89AD723-1F95-4521-8FC2-DFFA68AC4E84.jpg
Views:	170
Size:	37.7 KB
ID:	192390  
__________________
Al
astral highway is offline   Reply With Quote
Old 24th Oct 2019, 7:19 pm   #2
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 6,927
Default Re: Anyone ID this Loptx ?

It's an Ekco T161. Two versions were produced as this is the first version with the U25 mounted externally in a cradle with isolated heater winding. The heater winding of the early versions broke down to the core. The original heater winding for the EHT rectifier was then used to drive the small isolation transformer with a heavily insulated heater winding.
Later versions employed the familiar arched Perspex transformer. John.
Heatercathodeshort is offline   Reply With Quote
Old 25th Oct 2019, 9:43 am   #3
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,946
Default Re: Anyone ID this Loptx ?

Thank you , John! Brilliant help.

Can you signpost me go any relevant sets using it so I can see their line-output stage? And do you know the EHT voltage driven at the correct frequency?

Cheers
__________________
Al
astral highway is offline   Reply With Quote
Old 25th Oct 2019, 12:20 pm   #4
Cobaltblue
Dekatron
 
Cobaltblue's Avatar
 
Join Date: Dec 2010
Location: Exeter and Poole, UK.
Posts: 3,276
Default Re: Anyone ID this Loptx ?

The Model John gave is of the EKCO TV T161 the LOP valve was I believe a 20P1 the tube was designed for 10KV so I guess its there or thereabouts

Cheers

Mike T
__________________
Don't care if it was a bargain why's it in my kitchen
Mike T BVWS member.
www.cossor.co.uk
Cobaltblue is offline   Reply With Quote
Old 25th Oct 2019, 12:32 pm   #5
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,946
Default Re: Anyone ID this Loptx ?

Thanks , Mike.
__________________
Al
astral highway is offline   Reply With Quote
Old 29th Oct 2019, 10:57 am   #6
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,946
Default Re: Anyone ID this Loptx ?

Quote:
Originally Posted by Heatercathodeshort View Post
It's an Ekco T161...
John, fascinating.

It has a very unusual appearance for a line output transformer, doesnít it?

1) Itís in an alu can (presumably oil-filled instead of bitumen - itís vey light );

2) thereís no obvious EHT-tolerant lead or colour indication. (Iím assuming the central lead is EHT?)

3) there are long, flexible tinned wires for the other lead-pits

Do you have any details of the pinouts? This one appears to be NOS.

Cheers
__________________
Al
astral highway is offline   Reply With Quote
Old 29th Oct 2019, 12:41 pm   #7
Peter.N.
Dekatron
 
Join Date: Jul 2008
Location: Charmouth, Dorset, UK.
Posts: 3,329
Default Re: Anyone ID this Loptx ?

Never seen one of those, well familiar with the clear plastic ones that fall in half though.

Peter
Peter.N. is offline   Reply With Quote
Old 29th Oct 2019, 1:08 pm   #8
Cobaltblue
Dekatron
 
Cobaltblue's Avatar
 
Join Date: Dec 2010
Location: Exeter and Poole, UK.
Posts: 3,276
Default Re: Anyone ID this Loptx ?

Snips from trader 1039

Cheers

Mike T
Attached Thumbnails
Click image for larger version

Name:	T161 2.JPG
Views:	57
Size:	23.4 KB
ID:	192597   Click image for larger version

Name:	T161.JPG
Views:	59
Size:	38.4 KB
ID:	192598  
__________________
Don't care if it was a bargain why's it in my kitchen
Mike T BVWS member.
www.cossor.co.uk
Cobaltblue is offline   Reply With Quote
Old 29th Oct 2019, 2:11 pm   #9
turretslug
Nonode
 
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 2,940
Default Re: Anyone ID this Loptx ?

It's difficult to be sure but is the date 1958, rather than 1988?- the third numeral appears to be flat-topped, suggestive of a '5'. That would seem more credible, I know some stuff used to get stocked for a surprisingly long time but keeping a spare for a 405-line only TV for some 35 years after model introduction and 4 years after the transmissions closed down seems excessive!

Is the parallelled V9a in post #8 snippet 2 one half of the dreaded U801?
turretslug is offline   Reply With Quote
Old 29th Oct 2019, 3:07 pm   #10
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 6,927
Default Re: Anyone ID this Loptx ?

The circuit shows the resistance readings of the transformer so it should be easy to sort out the connections. The circuit does not show the U25 heater isolation transformer but all replacement transformers were fitted with the 'cradle'. [Later receivers employed the 3 link chassis with the familiar arched bridge Perspex housing] Reading technical notes of the time shows that all the early transformers broke down! Must have been a nightmare for such a reputable firm such as Ekco.
Yes TS. two anodes of the four anode U801 were employed as the boost diode.
The U801 with it's 80V heater was just a valve too far. Regards, John.
Attached Thumbnails
Click image for larger version

Name:	Ekco chassis. Early..jpg
Views:	57
Size:	64.7 KB
ID:	192608   Click image for larger version

Name:	Ekco T161 Early..jpg
Views:	62
Size:	85.2 KB
ID:	192609  
Heatercathodeshort is offline   Reply With Quote
Old 29th Oct 2019, 4:05 pm   #11
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,946
Default Re: Anyone ID this Loptx ?

Mike, thanks for the snippet...

So is T2, with the line drawn to ‘b’, EHT?
__________________
Al
astral highway is offline   Reply With Quote
Old 29th Oct 2019, 4:22 pm   #12
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 8,421
Default Re: Anyone ID this Loptx ?

Quote:
Originally Posted by astral highway View Post
Mike, thanks for the snippet...

So is T2, with the line drawn to ‘b’, EHT?
T2 is the circuit ref. for the transformer but yes the black circle in the center will be extra high voltage out (AC) to the EHT rectifier....Often referred to as "RF" by some folks in the servicing trade.

Lawrence.

Last edited by ms660; 29th Oct 2019 at 4:41 pm. Reason: clarify
ms660 is online now   Reply With Quote
Old 29th Oct 2019, 10:26 pm   #13
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,946
Default Re: Anyone ID this Loptx ?

Thanks, John.

Iím reading the snippet on a mobile device as no computer at the moment, so I canít see great detail.

Very detailed post, thanks!
__________________
Al
astral highway is offline   Reply With Quote
Old 30th Oct 2019, 4:07 pm   #14
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 6,927
Default Re: Anyone ID this Loptx ?

Hello Al, What are your thoughts on using the transformer? It is versatile for narrow angle tubes and simple line output circuits but has it's limitations due to it's early birth of flyback EHT. The original circuit was for a self oscillating line output stage but was changed on the later chassis. J.
Heatercathodeshort is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 3:48 pm.


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.