hpr4212 :: Replacing backup batteries in my Kenwood TS940S HF Radio Part 4
Part 4 deals with getting access to the PLL backup battery.
Hosted by MrX on 2024-09-24 is flagged as Explicit and is released under a CC-BY-SA license.
Amateur, Radio, DIY, repair, electronics, soldering.
2.
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Duration: 00:20:09
HAM radio.
A series about all things Amateur Radio/HAM Radio.
I mention the acronym PLL which stands for Phase Locked Loop. Here is a Wikipedia article about PLL.
Picture 1
shows a top down view of the radio. The large black square section
located at the front left of the picture contains the speaker left and
control board right. With the top cover fitted the control board is
accessible via s sliding cover. Both the speaker and control board need
to be removed in order to get access to the PLL backup battery. Both
come out as one piece.
Picture 2
shows the first three connectors that need removing from the control
board. All six connectors need removing before lifting the control board
and speaker.
Picture 3
shows the second three connectors that need removing from the control
board. Notice they are marked with the letter F.
Picture 4
shows one of the connectors removed. I was nervous removing these.
Fortunately I was able to remove them without causing any damage.
Picture 5
shows the speaker and control board lifted out of place and swiveled to
the side to reveal the PLL unit which is encased in a metal box for
screening. There are eight screws on the top lid that need removing to
gain access to the inside of the screened PLL unit.
Picture 6
shows the top cover removed from the screened PLL unit revealing the
backup battery located in the middle of the picture (Silver disc with
orange outer rim). The top cover is swiveled to the left hand side out
of the way.
Picture 7
shows a close up of the PLL backup battery. From the picture droplets of
liquid can clearly be seen on the right hand connecting terminal
indicating that the battery is leaking and must be removed before damage
occurs. On the right hand side of the picture notice the two connectors
attached to the circuit board that are terminated with unused sockets. I
have no idea what these sockets are used for. There are brass pillars
either side of the connectors. I assume some sort of add on board could
be purchased and perhaps this is what the unused connectors are for. I
also mention an unpopulated IC socket that can be seen in the top left
hand side of the picture. This is probably for another optional
extra.