Re: [Harp-L] MC-151 repair

["stephen.schneider" <stephen.schneider@xxxxxxxx>]

<There was a rumour I heard later from Stephen S. that he'd
heard somewhere that Astatic just stuck the stickers on them- they
were actually just relabled ceramics.>
 
I didn't believe that rumor, though--healthy late examples of both are distinguishable in an A/B playing test.  The story I heard and believed was that something had happened to the tooling for the MC-151 element's back casting, so they just used the MC-127 castings for all the elements, and put on stickers to distinguish the ones with crystal wafers.
 
I can vouch for BB and Joe's accounts of MC-151 innards, though I'm not sure one will necessarily see white salts in there.  I took apart a dead 1980s MC-151, and the crystal wafer had twisted and shriveled beyond repair, looked sorta like beef jerky.  I suspect that's what a heat and/or humidity victim looks like, and once you get under the metallic diaphragm, that should be obvious if that's what ails the element, as opposed to a victim of dropping, where the wafer is merely dislodged or has a loose actuating pin.  Before you get that far, I'd apply BB's method for working on the actuating pin's glued attachment to the center of the diaphragm (the corresponding attachment is visible from the outside of CR/CM elements, but is hidden underneath the perforated disk on Astatic elements).  If the element can be fixed without removing the diaphragm, you would save a lot of time/patience.
 
This discussion is probably tedious to some onlist, but it beats both mic myths and throwing away perfectly salvageable elements.  The CR/CM camp is going to have to come up with some new scurrilous rumors, though :-).