CurtZHP

OEP A262A3E with an open winding
« on: October 12, 2019, 05:40:33 PM »
I'm a bit flummoxed here.  I've got an OEP A262A3E transformer, and it appears that both secondary windings are open.  I measure no continuity whatsoever on either winding.  Primary windings are fine.

This thing was in a circuit where the secondaries were connected in series.

What could have caused this?

Excessive heat from soldering?
Age??

I checked the rest of the circuit for possible power supply rail shorts to those windings but found none.

Removed it from the circuit and measured it all by itself, and the secondaries are definitely open.
Electrons don't read schematics.


scott2000

Re: OEP A262A3E with an open winding
« Reply #1 on: October 12, 2019, 09:53:35 PM »
Quote
This thing was in a circuit where the secondaries were connected in series.

And it was working fine before?


CurtZHP

Re: OEP A262A3E with an open winding
« Reply #2 on: October 12, 2019, 10:21:01 PM »
Well, here's the thing.  I can't say for sure now.

It was in a known working preamp, but that preamp hadn't been used for some time.  I removed it from that device so I could "borrow" it for another one I was working on.  When that one wouldn't pass a signal at all, I began tracing things and discovered the open secondaries.

This is why I suspected soldering heat damage.  But, what are the chances that such a thing could result in BOTH secondaries taking a hit?

As mentioned earlier, I checked for power shorts and found none, and even if that had happened, there were other components that would have had to suffer damage and didn't.

Electrons don't read schematics.

scott2000

Re: OEP A262A3E with an open winding
« Reply #3 on: October 12, 2019, 10:52:43 PM »
I guess CJ may know more about possible heat damage... I wouldn't know...

data sheet attached


CurtZHP

Re: OEP A262A3E with an open winding
« Reply #4 on: October 12, 2019, 11:08:34 PM »
I'm trying to think of all the ways a transformer can end up with an open winding, and eliminate each possibility as the culprit.
Electrons don't read schematics.

gyraf

Re: OEP A262A3E with an open winding
« Reply #5 on: October 13, 2019, 01:51:57 AM »
Desoldering is very hard to the pin/wire connection inside


Jakob E.
..note to self: don't let Harman run your company..

CJ

Re: OEP A262A3E with an open winding
« Reply #6 on: October 13, 2019, 03:29:27 AM »
this is God's way of getting you to buy a Lundahl,  :D

or it could be that the coil wire has slipped out of the terminal eye, obviously you can not use tele-kenisis to fix it, some effort has to be put forth,  ie: desoldering the can or whatever it is potted in,
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

CurtZHP

Re: OEP A262A3E with an open winding
« Reply #7 on: October 13, 2019, 11:06:04 AM »
this is God's way of getting you to buy a Lundahl,  :D



You have no idea how ironic that statement is.

This particular transformer was originally installed in my Gyraf G9.   My plan, if this new project worked, was to take both OEP  input transformers out of the G9 and upgrade the G9 to Lundahls.

So, maybe God's telling me to put Lundahls in both preamps!  Or He's telling me to be more careful with what I have.....


 ;D
Electrons don't read schematics.

living sounds

Re: OEP A262A3E with an open winding
« Reply #8 on: October 13, 2019, 07:06:31 PM »
I've destroyed the internal connection of Lundahl transformers by desolderling, too.  ;D

CurtZHP

Re: OEP A262A3E with an open winding
« Reply #9 on: October 13, 2019, 07:53:02 PM »
My wife said it could be worse.

It could have been a Jensen.    :o
Electrons don't read schematics.


 

Related Topics

  Subject / Started by Replies Last post
19 Replies
11426 Views
Last post September 21, 2004, 07:05:37 AM
by Jazzy_Pidjay
6 Replies
2249 Views
Last post December 13, 2004, 04:04:43 PM
by clintrubber
6 Replies
1513 Views
Last post June 07, 2007, 02:27:47 PM
by Silvas
6 Replies
1608 Views
Last post August 19, 2007, 11:01:21 PM
by Ptownkid