Dead Transformer

alschmucker

Active Member
Hi Guys

Back again first project Harman/Kardon 560 Blew fuses as soon as pluged it in. After poking and proding around seems like the secondary has an internal short. Disconect the secondary leads from the power board short in board seems to go away but remains in the leads from the transformer to ground. There are only three leads two ends and a center tap. Al three read short to ground. They do have contunity to each other but there is no resistance from the ends or from the center tap to the ends. I would expect to see some reisitance in the secondary windings.
Hope it is not a door stop it has a interesting face.

Thanks Al
 
This happened to Optimus Prime in Transformers 2 Revenge of the Fallen. If you can locate some Energon you can fix this. It worked for Optimus!

Cheers
Mister Pig
 
With a fuse, have you tried the transformer just by itself without being connected to anything?

Except for the high voltage windings, most will show an ohm or two normally.
 
There are only three leads two ends and a center tap. Al three read short to ground. They do have contunity to each other but there is no resistance from the ends or from the center tap to the ends. I would expect to see some reisitance in the secondary windings.
When you write "no resistance", do you mean infinite ohms? Or do you mean zero ohms?

If the secondary is shorted to the transformer armature, zero ohms wouldn't be surprising.
 
Hi Guys

First off to Avonic if my posts are incorrect please forgive me as I am very new at this stuff. Any help I can recieve will be greatly accepted. And by the way I can't spell worth a crap, not my fortey. As for the amp I did not yet try it not hooked up good call I did not think of that.

Al
 
Sorry additional info contunity through transformer read 0 ohms dead short.
If the readings are correct, it's definitely a burned-out transformer. Something upstream of it may have shorted out and overheated the transformer, so it might not be the only problem.
 
As best as I can tell it is a split power supply What about the filter caps? If one or more shorts can it cause something like this?

al
 
I great.must apologize at this time pics are above my pay grade. I am trying to come up to modern age. With that said face time or something like that solve a lot of guestions and time. Still old school phones are great.
 
I can't spell worth a crap, not my fortey.
I'm sorry...but you made me laugh (forte).
There should be continuity between all leads of the secondary. If there is resistance, it should be very slight. There should not be continuity between the primary and secondary winding's.
Centre-Tapped-Transformer.jpg

Maybe this will help:
https://www.electronics-tutorials.ws/transformer/transformer-basics.html
 
So glad I could make you laugh. Seriously there is not enough lafter in the w2o9rld.
So glad yopu and the others responded. I am not sure what i8s going on here but I will tr4y with all your help.

Thank you Al
 
Hi Guys

. Disconnect the secondary leads from the power board short in board seems to go away but remains in the leads from the transformer to ground. There are only three leads two ends and a center tap. Al three read short to ground. They do have contunity to each other but there is no resistance from the ends or from the center tap to the ends.
Thanks Al
Not all that cut and dry.With the secondaries connected -It will appear shorted because your resistance measurement is reading through the transformer. Center tap is usually connected to chassis ground.
First off to Avonic if my posts are incorrect please forgive me as I am very new at this stuff.
OK .. Your forgiven...:biggrin:
 
I was kind of thing that. May be I should go ahead and seperate the front end from the power supply. And see if i can isoate what seema to be a short.
 
I was kind of thing that. May be I should go ahead and seperate the front end from the power supply. And see if i can isoate what seema to be a short.
If you haven't already done so (I thought you had done so, but perhaps I'm assuming too much), disconnect the transformer secondary leads and measure the resistance across them and between them and the metal body of the transformer.

If the transformer is good, you should see low resistance -- a couple of ohms or so -- across the secondary windings but infinite resistance between them and the transformer body.
 
As best as I can tell it is a split power supply What about the filter caps? If one or more shorts can it cause something like this?
Yes, it's a bipolar power supply. Shorted filter caps, shorted rectifier diodes, or shorted output transistors are all likely culprits if the transformer is burned out.
 
Thanks Dave.

Thats my thoughts I am thinking, but I am still very new at this. My carier was as an industrial election.

Please excuse me all of you, all of this is very new to me

Thank you
Al
 
Ok Dave

checked the secondary leads to frame of transformer infite ohms. No connection.
Ok I am not as smart as I thought I was. This is not going to be as easy as I thought it was.

Helpol

Al
 
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