HPR4212: Replacing backup batteries in my Kenwood TS940S HF Radio Part 4

Hacker Public Radio

Link to the YouTube video I used that described the process of removing the two backup batteries in a Kenwood TS-940S.

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.

I mention the terms pigtail and screened cables. Here is a link to a pigtail soldered to a screened cable.

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.