I appreciate your reply on this.   I have run tests on the AC and Constant DC outputs, and both are putting
out the proper voltages.  Was thinking that maybe the potentiometer may be bad on it.  I completed digital electronics school back in 1978 and have been a computer repair technician for over 30 years, hope this
alleviates your fears about my experience.   If you have pictures, or possibly a schematic, I would appreciate
copies of them.  You can send them to gwynnthreeATcoxDOTnet.   I have had the unit open and the inside is not
very organized, that's why I was looking for a schematic.  The pictures should help on sorting out the mess. 

I have an older Spectrum Magnum Ultra Plus transformer that has quit producing variable dc power.  Bachmann
no longer has any schematics or guides for this item as it is over 20 years old.  If anyone here has a copy
of the schematic and/or trouble shooting guide, I would appreciate being able to get a copy.  Also, if you have had this problem and know of a fix, I would appreciate that as well.  Thanks in advance.

George