Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: fritz203 on March 20, 2022, 03:43:00 pm

Title: Fender Deluxe Output Transformer testing
Post by: fritz203 on March 20, 2022, 03:43:00 pm

I tried to search for this topic, but couldn't find anything relevant.
Is there a way to test a Fender output transformer but just measuring the input/output winding ohms(not impedance)?
Thanks

Title: Re: Fender Deluxe Output Transformer testing
Post by: Kaaskop on March 30, 2022, 06:39:40 am

Might this help?

https://youtu.be/WiH-l5wRGBA (https://youtu.be/WiH-l5wRGBA)

Title: Re: Fender Deluxe Output Transformer testing
Post by: Latole on March 30, 2022, 07:20:02 am

Quote from: fritz203 on March 20, 2022, 03:43:00 pm

I tried to search for this topic, but couldn't find anything relevant.
Is there a way to test a Fender output transformer but just measuring the input/output winding ohms(not impedance)?
Thanks

No.
Only if windings read open you'll know it is bad.

Why do you want to test it ? What's wrong with the amp ?

Title: Re: Fender Deluxe Output Transformer testing
Post by: shooter on March 30, 2022, 10:04:06 am

Quote

input/output winding ohms

you'll want a good meter that can "zero" out probe errors since some of the readings will be in sub-ohms

Title: Re: Fender Deluxe Output Transformer testing
Post by: fritz203 on March 30, 2022, 02:58:11 pm

Ok, thanks for all your help, that is what I was looking for. 

Title: Re: Fender Deluxe Output Transformer testing
Post by: Latole on March 30, 2022, 03:06:47 pm

Quote from: fritz203 on March 30, 2022, 02:58:11 pm

Ok, thanks for all your help, that is what I was looking for.

Why do you want to test it ? What's wrong with the amp ?

Right DC resistors do not mean transformer will work / sound fine

Title: Re: Fender Deluxe Output Transformer testing
Post by: fritz203 on March 31, 2022, 10:16:22 am

I figured out the transformer is fine, that was just a part of the troubleshooting. I had a screen resistor burn out and that took out the output tubes, so I wanted to check the transformer also. It turns out I had the output tubes biased too hot. All is fixed now. Thanks.

Title: Re: Fender Deluxe Output Transformer testing
Post by: Latole on March 31, 2022, 10:24:38 am

Good news !

What is the amp we are talking about ?

Title: Re: Fender Deluxe Output Transformer testing
Post by: Latole on April 01, 2022, 05:25:59 am

Useful ?

Title: Re: Fender Deluxe Output Transformer testing
Post by: pdf64 on April 01, 2022, 06:35:53 am

A 'hard' fault on a push pull OT primary may be revealed by comparing the full primary resistance to the sum of the CT to anode resistances.

Title: Re: Fender Deluxe Output Transformer testing
Post by: PRR on April 01, 2022, 01:58:57 pm

RG Keen has a transformer shorts tester.

(https://cdn.shopify.com/s/files/1/1091/4404/products/TransformersAutobotShortsfront.jpg)

Title: Re: Fender Deluxe Output Transformer testing
Post by: Latole on April 01, 2022, 02:59:31 pm

Quote from: PRR on April 01, 2022, 01:58:57 pm

RG Keen has a transformer shorts tester.

Him ?

R.G. Keen
Cheif Engineer
Visual Sound
www.visualsound.net

Title: Re: Fender Deluxe Output Transformer testing
Post by: PRR on April 01, 2022, 03:04:45 pm

Yes but no. His personal site Geofex. http://www.geofex.com/  http://www.geofex.com/ampdbug/outtrans.htm
 

Title: Re: Fender Deluxe Output Transformer testing
Post by: Latole on April 01, 2022, 03:07:39 pm

Quote from: PRR on April 01, 2022, 03:04:45 pm

Yes but no. His personal site Geofex. http://www.geofex.com/  http://www.geofex.com/ampdbug/outtrans.htm

Thank's

Title: Re: Fender Deluxe Output Transformer testing
Post by: fritz203 on April 04, 2022, 03:40:11 pm

Ok, thanks again.