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 Audio (record players, hi-fi etc)

Notices

Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

Closed Thread
 
Thread Tools
Old 2nd Mar 2006, 7:26 pm   #1
jsel84
Retired Dormant Member
 
Join Date: Sep 2003
Location: USA Long Island New York
Posts: 28
Default Testing Push Pull Output Transformers

I've been working on some amplifiers of this type and been finding the output transformers to be shorted.
I have few that may be a good match, but not sure of their speaker ohms and if they are good.
Is there an easy test to check the primary and the secondery on these transformers with a Fluke Multi Meter to see if they are sure to be good
Also how would one find out the ohms on the speaker side,
Thanks for any advise

Regards,
Jim
jsel84 is offline  
Old 2nd Mar 2006, 9:02 pm   #2
GMB
Dekatron
 
GMB's Avatar
 
Join Date: Aug 2003
Location: near Reading (and sometimes Torquay)
Posts: 3,086
Default Re: Testing Push Pull Out Put Transformers

If you don't have any equipment to directly measure the turns ratio then feed a few volts a/c into the speaker winding and measure all the voltages with an a/c voltmeter. From this you can calculate the turns ratio, being the ratio of the voltages. Then the primary impedance is the speaker impedance times the turns ratio squared.
GMB is offline  
Old 2nd Mar 2006, 9:17 pm   #3
Ed_Dinning
Dekatron
 
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,171
Default Re: Testing Push Pull Out Put Transformers

Hi Jim, thats about the best way to test an OP tranny as JMB says. It will not normally show up a few shorted turns. This can be a common fault, especially on guitar amps and it difficult to detect without pulse testing gear.

Ed
Ed_Dinning is offline  
Old 2nd Mar 2006, 10:51 pm   #4
Radio_Dave
Nonode
 
Radio_Dave's Avatar
 
Join Date: Jun 2004
Location: Norwich, Norfolk, UK.
Posts: 2,543
Default Re: Testing Push Pull Out Put Transformers

Hi Jim,

Everything is explained very well on this page

http://www.radioremembered.org/outimp.htm

HTH
David
Radio_Dave is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 4:29 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.