New sounder/old transducer



My 25 year old FCV-662 sounder died. Can I install a LS-4100 using my existing through-hull transducer (520-5MSB)? I know the cable plugs are different-I was going to cut the old plug off and splice a new one on. Otherwise the boat would have to be hauled to install the right transducer and I was looking for an easy fix. Thanks all!
I don't find the 520-5MSB listed for the FCV-662. However if your transducer has a 8-pin plug you can use the 8 to 10-pin adapter cable (AIR-033-073) for the LS-4100.

My old FCV-662 sounder transducer plug has 6 pins in a round configuration.
In looking though the op manual the six pin plug is just for Speed & Temp. The three pin connector is the transducer, do you see that?

Snips is correct. The FCV662 has a three pin transducer connection. If you want to use a newer type sounder like the LS4100 with this older transducer, you will need to manually wire a suitable 10 pin connector. This would be done with a 10 pin pigtail cable (Furuno P/N AIR-033-333). If you provide the color code you have on the wires going to each pin of the three pin connector; I will provide you a wiring color code between your existing transducer and the pigtail cable.
You guys were right about the 3 wire transducer cable; the 6 pin is the speed and temp. I cut the transducer cable back and found a black and white wire, both encased in a shielded cable. Looking at the schematic for the Airmar-033-333 cable, it looks like pin numbers 7,8,9 and 10 are for the transducer. I would connect the black wire to black, the white wire to white and the shield to shield. What is the blue wire used for and what do I do with it, on the Airmar 033-333? Thanks , appreciate the help.
Here is the pin out for the Furuno 10 pin transducer connection.

You would be using pin 8,9,10
Blue, Black and Shield.

Old transducer ----- 10 pin Pigtail cable
Black ---------------- Black (Pin 10)
White ---------------- Blue (Pin 8)
Shield ---------------- Shield (Pin 9)

You would NOT connect WHITE (Transducer +) of the old transducer to the WHITE (TEMP) of the pigtail.
Johnny Electron - haven't been able to do the wiring change yet but thank you very much for the information. Will attempt do the job on Saturday and let you know the results. Thanks again!
Johnny Electron - Rewired the transducer cable and it works great! Thanks again for your help.
Just revisiting this old thread as I am replacing the plug into my 585 from my M260 Airmar.

As I run a seperate speed/temp unit with the Y cable into the 585 .... I am only interested in terminating the sounder/depth cables into the plug (Blue and Black - # 8 and 10).

My question is around the bare shield cable #9. Is that absolutley required .... and if yes what function does it serve? I would be interested to know what happens if I don't terminate it into the plug and just run with 8 and 10.

Thanks guys

Does the shield wire need to be connected, no. Should it be connected, yes. The shield wire in a transducer cable helps prevent unwanted noise from getting into a sounder through the transducer leads. It really depends on how quiet the environment is if you would see any difference connecting the shield wire or not. If you were on a smaller vessel with few electrical systems you probably wouldn't see any difference. If you were on a larger vessel with inverters, fans, fluorescent lights, etc you would probably see background noise on the sounder without the shield connected. If it were my boat I would connect it.