Originally Posted by Hugh Laubis:
Buzzing e units can be fixed. did many years ago. May have pictures yet somewhere and will look for them.
Issue is the E unit plunger travel and being fed with AC. I recall glueing a thin piece of foam material to prevent plunger travel from allowing it to seat all the way upward. This also helped the plunger from failing to drop between cycles.
I will look in my files tonight. I think also in later years I added a full wave rectifier to feed the circuits with DC rather than AC to eliminate buzz altogether. I will look tonight after a round of golf.
I have researched my old notes and offer this information based on my years of working on Lionel E-Units. It is information learned and lifted from a variety of sources and there are other excellent experts on this site about these techniques.
First, let me say that my recollection of glueing a piece of matchbook cover to prevent total travel of the plunger to the top was placed on top of the pawl and its only purpose was to prevent the E-Unit from hanging up, not necessarily prevent the ‘BUZZ’.
Secondly, a simple easy method is to adjust the pawl. It works, but only on some units. E-units can be adjusted to eliminate much of the buzz by slightly straightening the arm that hangs down from the plunger that catches the e-unit drum. Just straighten out the arm a little at a time until most of the buzz is gone but the e-unit still cycles. If the arm is straightened too much the e-unit will be sporatic in operation.(hanging up) If this happens just slightly add a little bent back to the arm until it cycles properly, or add the glued on piece. With a little practice this may be all you need.
Finally, the electronic fix is the best but requires some work.
It is about 10 millimeters in diameter and rated at about 1.5 amperes, 50 volts or more. The 4 leads are probably marked +, -, ~, and ~.
Disconnect the coil from the two terminals where it is now connected. Connect the rectifier's ~ leads to those terminals. Connect the coil to the rectifier's + and - leads. So, before:
(e-unit terminal 1)---(coil)---(e-unit terminal 2)
After:
(e-unit terminal 1)---(~ rectifier +)---(coil)---(- rectifier ~)---(e-unit terminal 2)
I, however, mostly used this bridge rectifier from radio shack as usually there was plenty enough room for it in the cab interior.PN 276-1181.