Garage door opener power supply transformer has an opened primary. It's
actually a burnt coil wire right on the pin. I did manage to solder it
back on but I'm worried it may fail again.

It's a 38V CT. Of course I can't find the *exact* replacement, but can
I use a 36V CT ?

Thanks,

Yes you should be OK ..

kip
wrote in message
oups.com...
Garage door opener power supply transformer has an opened primary. It's
actually a burnt coil wire right on the pin. I did manage to solder it
back on but I'm worried it may fail again.

It's a 38V CT. Of course I can't find the *exact* replacement, but can
I use a 36V CT ?

Thanks,

"kip" writes:

Yes you should be OK ..

Or, have confidence in your repair. If it failed at the pin, it was a
solder problem, not something more ominous.

If the new soldering was done properly, it should last. If it were something
else, it's likely the failure would be inside.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.


kip
wrote in message
oups.com...
Garage door opener power supply transformer has an opened primary. It's
actually a burnt coil wire right on the pin. I did manage to solder it
back on but I'm worried it may fail again.

It's a 38V CT. Of course I can't find the *exact* replacement, but can
I use a 36V CT ?

On 24 Aug 2005 09:13:10 -0700, wrote:

Garage door opener power supply transformer has an opened primary. It's
actually a burnt coil wire right on the pin. I did manage to solder it
back on but I'm worried it may fail again.

You better be worried about a fire hazard !
There usually is a good reason for a transformer to burn it's
coil.

There is nothing basically wrong with resoldering the part, but
_please_ make sure that there is some thermal cutout device in
the circuit. (And that it is thermically coupled to the
transformer.)

--
Kind regards,
Gerard Bok

On Wed, 24 Aug 2005 17:57:24 GMT, (Gerard Bok) wrote:

On 24 Aug 2005 09:13:10 -0700, wrote:

Garage door opener power supply transformer has an opened primary. It's
actually a burnt coil wire right on the pin. I did manage to solder it
back on but I'm worried it may fail again.

You better be worried about a fire hazard !
There usually is a good reason for a transformer to burn it's
coil.

There is nothing basically wrong with resoldering the part, but
_please_ make sure that there is some thermal cutout device in
the circuit. (And that it is thermically coupled to the
transformer.)

Don't most/all transformer primaries have this?

Tom

On Wed, 24 Aug 2005 20:18:13 GMT, Tom MacIntyre
wrote:

On Wed, 24 Aug 2005 17:57:24 GMT, (Gerard Bok) wrote:

On 24 Aug 2005 09:13:10 -0700, wrote:

Garage door opener power supply transformer has an opened primary. It's
actually a burnt coil wire right on the pin. I did manage to solder it
back on but I'm worried it may fail again.

You better be worried about a fire hazard !
There usually is a good reason for a transformer to burn it's
coil.

There is nothing basically wrong with resoldering the part, but
_please_ make sure that there is some thermal cutout device in
the circuit. (And that it is thermically coupled to the
transformer.)

Don't most/all transformer primaries have this?

They should have. (But I wouldn't bet on it.)

Depending on where you live, extra care should be taken when you
do the repair yourself.
If there is a fire, an insurance company may require proof that
you didn't tamper with any fireprotection that was present in the
device.

--
Kind regards,
Gerard Bok

Thanks for all the replies. What made me decide to replace the
transformer was that I just didn't think the initial repair would hold,
it was rather delicate to do. I had resoldered the tiny copper strand
back on the solder tab, I think the strand still had some
lacquer/glue/adhesive on it after attempting to clean it, and had less
than a millimeter of play; I just wasn't satisfied I had enough contact
surface and it was difficult to properly and cleanly wet the joint.
Ugh.

I ended up installing the replacement transformer, a 36v CT 1A unit
riveted outboard on the chassis, the original being 38v CT 500mA, and
cleanly tiewrapped the cabling to an existing harness and onto the PCB.

I measured the same voltages on the various screw terminals as with the
previous (flaky) transformer.

The fuse hasn't blown yet, and I have a fire extinguisher handy :-)

Thanks to all,