UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV 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 11th Aug 2023, 10:22 am   #1
paul farn
Triode
 
Join Date: May 2023
Location: Epsom, Surrey, UK.
Posts: 32
Default SMPS chopper transformer.

Can a chopper transformer be tested for shorted turns? Got a LOPT tester courtesy TV mag but would it work on above? Probably not.
P.
paul farn is offline   Reply With Quote
Old 11th Aug 2023, 10:27 am   #2
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,132
Default Re: Don't know

I've used a ringing tester built from Television magazine to test chopper transformers. It seems to pick up shorted turns OK, as you might expect. After all, it just shows that the oscillations are heavily damped due to the energy absorbed in the shorted turn.
TonyDuell is offline   Reply With Quote
Old 11th Aug 2023, 12:40 pm   #3
toshiba tony
Heptode
 
toshiba tony's Avatar
 
Join Date: May 2006
Location: Accrington, Lancashire, UK.
Posts: 973
Default Re: Don't know

Might be related but I used to "ring" lopts. Just attach the two top connections to check line output transformers. If you got EHT on the primary you could assume the transformer was good, never let me down.
toshiba tony is offline   Reply With Quote
Old 12th Aug 2023, 10:44 am   #4
paul farn
Triode
 
Join Date: May 2023
Location: Epsom, Surrey, UK.
Posts: 32
Default Re: Don't know

Quote:
Originally Posted by TonyDuell View Post
I've used a ringing tester built from Television magazine to test chopper transformers. It seems to pick up shorted turns OK, as you might expect. After all, it just shows that the oscillations are heavily damped due to the energy absorbed in the shorted turn.
Have you got a copy of this cct?It sounds like the right device for the job.I would think you also need a 'scope to view.Is that right?
P.
paul farn is offline   Reply With Quote
Old 12th Aug 2023, 11:57 am   #5
Graham G3ZVT
Dekatron
 
Graham G3ZVT's Avatar
 
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,645
Default Re: SMPS chopper transformer.

To get this shot, I think I simply had one probe on the Y input and the other on the Cal output and connected them across the primary winding of the Loptx I was testing.
Attached Thumbnails
Click image for larger version

Name:	ring.jpg
Views:	140
Size:	69.6 KB
ID:	283169  
__________________
--
Graham.
G3ZVT
Graham G3ZVT is online now   Reply With Quote
Old 17th Nov 2023, 11:06 am   #6
paul farn
Triode
 
Join Date: May 2023
Location: Epsom, Surrey, UK.
Posts: 32
Default Re: SMPS chopper transformer.

Applied ringing test to device as described ie:cal-winding-i/p.Acceptable trace obtained similar to above.
Power diode shorting on sec which I should've checked earlier.Could've saved ages.Ah didnae ken.
Put it all back together & not a bad picture considering tube is 38,TX 100 series.Is this a record?
A few other components want replacing sometime.....
paul farn is offline   Reply With Quote
Old 17th Nov 2023, 11:57 am   #7
its ur aerial
Hexode
 
its ur aerial's Avatar
 
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
Posts: 413
Default Re: SMPS chopper transformer.

That Diode was a common fault back in the day, was it D22, a BY298 memory fading.

Ken G6HZG.
__________________
Life is not Hollywood, life is Cricklewood.
its ur aerial is offline   Reply With Quote
Old 20th Nov 2023, 11:34 am   #8
paul farn
Triode
 
Join Date: May 2023
Location: Epsom, Surrey, UK.
Posts: 32
Default Re: SMPS chopper transformer.

Quote:
Originally Posted by its ur aerial View Post
That Diode was a common fault back in the day, was it D22, a BY298 memory fading.

Ken G6HZG.
It was the other one actually.D15(byw74).
P.
paul farn is offline   Reply With Quote
Old 21st Nov 2023, 7:24 am   #9
its ur aerial
Hexode
 
its ur aerial's Avatar
 
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
Posts: 413
Default Re: SMPS chopper transformer.

Paul, thanks for jogging the memory
Ken G6HZG.
__________________
Life is not Hollywood, life is Cricklewood.
its ur aerial is offline   Reply With Quote
Old 21st Nov 2023, 9:10 am   #10
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,647
Default Re: SMPS chopper transformer.

All transformers can be tested by a ringing technique, though sometimes you may need to add a capacitor to get a ring frequency you can use. Interpretation might be best by comparison with a known good one. For RF transformers you need a fast-edged pulse generator and a fast scope or a TDR.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 9:49 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 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.