[R-390] OT: Speaker update - part dieux

[Bill Smith]

Did the fingernail polish shrink and warp the cone?  You can try shims and
the water treatment, but the problem may be that the fingernail polish will
continue to shrink and warp.  I have run across at least one very contorted
cone which had been repaired with some clear plastic substance.  It was
literally curled.  Had quite a time removing it - think it took laquer
solvent or methyl-ethyl keytone, or both.

Bill

----- Original Message -----
From: Scott, Barry (Clyde B)
To: R390 (E-mail)
Sent: Wednesday, August 20, 2003 11:44 AM
Subject: RE: [R-390] OT: Speaker update - part dieux


It appears I now have a new step to add to this procedure:

a.  Go home at lunch the following day.  Press speaker cone and hear the
scratchy noise again...sigh.

Perhaps this was moisture related - it worked before all the solvent had
fully evaporated.  Not sure.  It may still play acceptably, but it seems
that rubbing is back although not quite as loud as it was.

Looks like I'll probably just find a good replacement.

Barry(III) - N4BUQ


-----Original Message-----
From: Scott, Barry (Clyde B)
Sent: Wednesday, August 20, 2003 9:32 AM
To: R390 (E-mail)
Subject: [R-390] OT: Speaker update


I decided that with all the good advice I received from this list, I would
attempt to repair my scratchy speaker.  Here's how I did it.

1.  Picked most of the felt from the center.  Pulled some tiny flecks of
speaker cone with it so decided to use a bit of solvent.

2.  Wetted a cotton swab with finger-nail polish remover.  Accidentally
splashed about a thimble-full of solvent on the speaker cone in the process.
Speaker cone became mushy and began to separate from the voice coil.  Not
looking too good at this point.  Set speaker aside to allow "solvent" to
dry.

11.  Used clear finger-nail polish (didn't have any other appropriate
cement) to strengthen the bond between cone and voice coil.

5.  Attempted to push a piece of cellophane tape between the voice coil and
magnet.  Considered this equivalent to stacking marbles and decided not to
push what little luck I had left.

A.  Tapped speaker upside-down on desktop to try to dislodge trash in voice
coil.  Think I saw some small particles come out, but that may have simply
been pieces of the foam cushion that were disentegrating as a result of step
#3.

B.  Used cotton-swab and compressed air (okay, I blew into it since I don't
have a compressor) to clean anything else I could see in voice coil/magnet
area.

9.  Noticed scratchy sound no longer seemed to be evident.  Connected to
signal generator.  Small buzz still evident at ~200 cycles.  Added more
clear finger-nail polish around center ring.

10.  Connected speaker to R390A.  Sounded fine.

12.  Cut a round disc from a manilla file folder and "glued" it (with more
finger-nail polish) to replace old felt center.

2.  Connected speaker to stereo.  Sounded great.

XIV.  Used black Sharpie(r) pen to "paint" center disk so it isn't as
visible through picket-fence grill in the Trans-oceanic.  Looks great!

Many thanks again to the suggestions from this list.  Hmmm.  With this under
my "belt", perhaps I can fix that sticking meter in my Hickock 651A...

Barry(III) - N4BUQ
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