[ICOM] HM-56 - PCB contamination ?

[Jens Schmidt]

Hi all,

While looking for any polarisation marks
on the PCB in preparation for replacing
the electrolytics, I spotted something
next to C7 that looked a bit like a melted
component.
As I could not identify it, I gave it a
nudge with the flat end of my toothpick.
The whole thing came away, and turned out
to be a gooey sticky mess, containing some
of the green masking lacquer.
The position of the blob turned out to be
a via in the board.
On much closer inspection it was noticeable
that there were many spots on the PCB that
had this semi liquid substance.
For the time being, I have scraped and wiped
with toothpick and cotton tips.

Have any of you seen this on your mikes or
other Icom equipment ?
What would it be ?
The first and largest lot was close to one
of the electrolytics, but most of the others
were nowhere near.
The mike has never been dunked in any liquid,
neither is it subject to moisture condensation.

What further reasonable cleaning should I do ?

This attempt at maintenance was not undertaken
because of the the dreaded TX-lock-up, but as a
first step in trying to fix the DTMF problem.
That problem has manifested by a need to up the
mike gain on the IC-275, over some months, till
it now fails to work.
No complaints about my audio level, and it is
not the receiving equipment, because other DTMF
gear on the same antenna works OK, any help with
that side of the issue ?

73 Jens ZL2TJT