Need help replacing transformer

[elimenohpee]

I'm repairing a board that looks to have a broken power transformer but I'm having trouble finding a replacement.  The primary and secondary has 4 pins on each side, but the coils are attached only to pins "1" and "4"; the inner pins "2" and "3" are unused and look to only be used as a mechanical support.  When I look on Digikey, I can only find transformers that have secondary's with multiple circuits with the option to parallel or series the circuits together.  The board doesn't route those pins so those transformers won't work in this situation.  I'm sure these transformers are out there, I just don't do repairs like this very often and am not able to find them.

As far as selecting the replacement, the primary is mains fed (115 VAC) and the secondary goes through a full bridge rectifier to a 5V regulator with a 2V dropout voltage.  I measured the secondary current draw and it is less than 100 mA. 

Thanks for all the help

[jaruco]

What you are looking for is called a split bobbin type of transformer. A quick search on the web revealed many hits. Since you already know the voltage and current requirements, finding a suitable replacement should be easy. Regulator circuits that use something like a 7805 require an input voltage that is at least 1.2V above the desired output voltage to function correctly. Be aware that any voltage that exceeds that will have to be dissipated as thermal energy by the regulator so a secondary voltage of 7-9V should be satisfactory.  Take a look at the "images" when you search for this. Russ

[tautech]

Check the primary winding for a open thermal fuse......not uncommon.
It should be under the tape at the end of the winding.

Be sure to add a fuse if you're going to bridge or remove it.