Wiring problem garmin 120 fishfinder

Dino · 20 January 2006, 17:35

I'm really struggling to get the transducer lead under the deck to the console because of the size of the plug at the instrument head end,has anyone ever cut the cable and rejoined it again under the console?
If so did it affect the performance? A marine engineer has told me its ok but I would like to hear from someone who has done it as the Garmin manual says not to as it will invalidate the warranty.

Hugh Jardon · 20 January 2006, 17:43

tis only cable at the end of the day so no real mystery there really, if you cut the cable ensure you re connect it correctly and ensure a water tight connection. use some heatshrink over the connectors and perhaps self welding tape etc, lots of different products out there so use which you think will do the job best.

i am going to cut the bnc connector off my garmin mushroom thing and then reconnect a new bnc connector to save drilling larger holes in the aframe. but i have all the right equipment to put on the bnc connector and proof it

Quote:

Originally Posted by Dino

I'm really struggling to get the transducer lead under the deck to the console because of the size of the plug at the instrument head end,has anyone ever cut the cable and rejoined it again under the console?
If so did it affect the performance? A marine engineer has told me its ok but I would like to hear from someone who has done it as the Garmin manual says not to as it will invalidate the warranty.

Dino · 20 January 2006, 17:55

Thanks hugh,I was worried it was co-ax in there,that was what was putting me off cutting it,I'll crack on!

Hugh Jardon · 20 January 2006, 18:17

connect it up prior to cutting the cable so you can check it works, not sure if a bucket of water will do the trick or if you are close to the sea etc, probably difficult to test until you are actually out there

Quote:

Originally Posted by Dino

Thanks hugh,I was worried it was co-ax in there,that was what was putting me off cutting it,I'll crack on!

Neal · 20 January 2006, 19:03

Dino,
I cut the plug off the car GPS (not the same I know but close) installed the cable then joined/soldered it back together and all has been OK. This also against the advice of the people that provided it but I did not want big holes is the dash

jwalker · 20 January 2006, 19:19

Quote:

Originally Posted by Neal

Dino,
I cut the plug off the car GPS (not the same I know but close)

Not the same at all. There is a considerable pulse of energy transmitted down the sounder cable and everwhere there is a joint there is also a reflection. It is easy to envisage a considerable reflection travelling back along the cable until it reaches the connection on the head unit where some of it will be reflected back down the cable until the joint and then some of it will be reflected back etc, etc. In this way a standing wave will be set up on each transmitted pulse and on the returned pulse from the sounder a similar thing will happen. Whether the units at either end will be able to cope with this is anyone's guess.

I suspect you'll find individual screened leads inside the cable and, maybe, an overall screen too. They'll likely be aluminium foil so it will be difficult to make good soldered connections.

As to whether you should cut it. If I had no alternative, I would.

Hugh Jardon · 20 January 2006, 19:23

at least when you go fishing you may see loads of fish