Old ekco tv transformers - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th May 2014, 08:13 AM   #1
diyAudio Member
 
Join Date: Mar 2014
Default Old ekco tv transformers

Hello. I have the guts of an old tv I pulled out of a skip. It had been robbed of all its tubes, mashed up and tossed aside. Shame cos it was a very beautiful ekco tv once. Anyway it is now dead so I would like to test the transformers to see if they are usable. There are four transformers in this thing, one is the output tran' of a single ended output stage, one is quite small and I have not looked at the circuitry around it to even begin to fathom its use. Another is in the power supply and I guess it is a 1:1 ?? But would this be rated for 240VAC, I guess so as the set is ac/dc, but I would just like some confirmation before a go throwing what is actually 272VAC in this area, at it. There is one last transformer of the same size, shape, number of windings and my guess is also a 1:1. could anyone that knows these old TV's let me know what I am playing with please. Thanks
  Reply With Quote
Old 13th May 2014, 08:42 AM   #2
diyAudio Member
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
You are playing with a live chassis TV. That means the mains is connected directly to the set and as it is AC/DC there is no mains transformer.
There will be an audio output transformer, a Line output transformer (tuned to either 405 line 10kHZ or 225 line 7kHZ approx) and a frame output transformer tuned to 25HZ,
__________________
www.flyingmole.co.uk For World Wide support for Flying Mole, Class D, Refurbishment and Repairs. www.jonsnell.co.uk
  Reply With Quote
Old 13th May 2014, 08:43 AM   #3
diyAudio Member
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
If you disclose the model number, that would be useful for service information.
__________________
www.flyingmole.co.uk For World Wide support for Flying Mole, Class D, Refurbishment and Repairs. www.jonsnell.co.uk
  Reply With Quote
Old 13th May 2014, 09:25 AM   #4
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Quote:
Originally Posted by JonSnell Electronic
tuned to either 405 line 10kHZ or 225 line 7kHZ approx)
625 lines 15625Hz?

Quote:
frame output transformer tuned to 25HZ,
Frame OPT 50Hz but probably untuned.

A very old TV might have a mains transformer, but this might feed the valve heaters only. As Jon says, a model number will help.
  Reply With Quote
Old 13th May 2014, 10:36 AM   #5
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
The heaters were usually wired in series with a large dropper resistor to get rid of the excess voltage.
  Reply With Quote
Old 13th May 2014, 11:18 AM   #6
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Yes, but very early TV might be different. We have no idea how old this TV is.
  Reply With Quote
Old 14th May 2014, 11:50 PM   #7
diyAudio Member
 
Join Date: Mar 2014
Unfortunately the back was removed and I could not find it and I can not see a model number anywhere on it. I have no intention of plugging this thing in as I have no doubt that it is very dangerous even for those who do know these TV's. maybe if I look where the prim/sec are wired to someone may be able to have an educated guess of what one is what? I will try to give description of the remaining two unknown transformers and what they are wired to, tomorrow if one of you guys could help please? Thanks for replies I will update. For now, maybe this will give an idea of age....tv contained a u191 30p4 and possibly u26 (first letter is u second digit missing and third is a 6) but the cathode has a slightly different shape. The top of it is the same but going down toward the pins it looks like what I can only think to describe like, if you take a coke can and cut off the bottom and then cut 4 oblong sections out lengthways two large at opposite and two small opposite each other that is the shape of the cathode. Anyway those ones left inside as they was shielded by a half cylinder metal plate. Thanks for reading my waffle

Last edited by jimmiegin; 14th May 2014 at 11:53 PM.
  Reply With Quote
Old 15th May 2014, 03:57 PM   #8
seppoa is offline seppoa  Sweden
diyAudio Member
 
Join Date: Feb 2013
An AC/DC set never have a powertransformer, and the tube types point to serial heater chain. Some early sets had the HT to the picturetube, several kVolts, delivered from a mainstransformer, a big one but only in pure AC-sets.
One trafo is surely for the vertical deflection, one for audio out. One can possibly be a choke for the +B.
The description of the tubes electrode leads me to think that it is the anode you are talking of, a Beam Tetrode possibly. Does it have a top connection? Then it is the horizontal output tube (or valve for UK readers )
  Reply With Quote
Old 15th May 2014, 07:53 PM   #9
diyAudio Member
 
Join Date: Mar 2014
It is indeed a vacum tube thermionic valve with the cathode conected to the top of the glass tube.(TRAF 1) One of the transformers is definately the output traf that does not appear to be air gapped but the center tap on the tube side is connected by cap resistor to one and other end of the windings, is this a usual arangement for a pp traf?. (TRAF 2) large transformer...... Has only a single winding and is connected one end to a really BIG cap (pysically size), and the other end of the winding is connected to a very tightly wound inductor of fine wire that is wound around a twig! with nails in it for teminals! (TRAFF 3)Is of same size core, but has two windings. (TRAF 4) Is the smallest, about the size one might expect in a 12 volt 500MA wall adaptor, i can see that at least one end of one winding is connected to pin one of an octal based 9 pin but that could surely mean anything?. This also has two windings. This set has two really big dropper resistors and i will try now to post some pictures but i do not know if thay will help at all. Thanks guys .... tuned or untuned to set frequency? what are the ramifications of running a tuned transformer at the wrong freq, and by "tuned" does it mean they are wound to a set tpv ratio for core size/frequency????
  Reply With Quote
Old 15th May 2014, 07:58 PM   #10
diyAudio Member
 
Join Date: Mar 2014
Default Pictures of old tv transformers

WP_000293.jpg

WP_000294.jpg

WP_000295.jpg

WP_000296.jpg


Maybe these pictures will help?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tv power transformers for audio use? yero Power Supplies 16 28th April 2012 01:17 AM
ekco ui59 receiver mpleasant Tubes / Valves 4 13th March 2011 10:38 PM
211/VT4C test data for TV-7 / TV-10 Doctorcilantro Parts 0 24th October 2008 06:41 PM
4 SALE!! avermedia tv genie vga tv tuner capture device... thing.... 4 SALE!! lone_wolf_84 Swap Meet 0 3rd February 2005 12:26 AM


New To Site? Need Help?

All times are GMT. The time now is 01:54 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2