Re: help replacing an old ac power transformer.

fotoobscura@xxxxxxxxx wrote:
John I can email a small digital photo ...

You are welcome to do so. There is also a newsgroup that welcomes picture attachments called alt.binaries.schematics.electronic but you can't post to this through Google groups.

Does this help: This is a photographic enlarger and has a 27V GE bulb
inside it (thats the only thing thats being powered by the
transformer/power supply).


That really narrows the possibilities a lot.

I am not absolutely sure the transformer is bad, I guess.  I presumed,
perhaps incorrectly that the relatively loud buzzing sound when turning
it on was the culprit but that may be presumptuous?  The power
supply/transformer are separate from the photographic enlarger.

The bulb doesn't look *physically* blown so I doubt its the bulb.

Do you have a multimeter (a digital one cost less than $20 at Walmart)? This will let you check the output voltage when the power is on, and the winding resistance when the line cord is unplugged. You can also check that the filament is intact with the ohm meter.

The wire looks like regular household wiring gauge (12ga?) but is much
more pliable.

Hope this helps more..

It does. Is this a color enlarger (where the bulb temperature is really important? Are you sure there is no electronics between the transformer and the bulb? If not, you are probably looking for a 27 volt 3 ampere transformer. Unfortunately, 24, 25 and 28 volt transformers are all more common.

For instance these from Digikey http://www.digikey.com/
http://rocky.digikey.com/WebLib/Hammond/Web%20Data/166%20Series.pdf



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