Replace/Retrofit depth finder in 1996 2100SR

[mcoffey]

Hi all, figured I would post my recent fun in replacing the stock depth finder in my 96 2100SR.

For starters, the factory unit is a Humingbird HDR200 and is labeled as such on the rear of it. It mounts to the dash using 4 philips screws that go through the flat front face that covers the LCD of the unit. The wood toned dash panel then attahes to the dash with double sided foam tape and has a recetangle cutout just large enough to see only the LCD screen. All wires exit out the rear and these unclude transducer wires, alarm wires and alarm as well as power, ground and alarm set/on wires.

Now for the fun part. I found a new HDR200 on ebay for $75.00. It is not the OEM version that s used in Maxum but rather a standard dash mount aftermarket depth finder. This unit is meant to slide into a 2-1/8 hole with a bracket attaching from the rear to lock it to the dash. The face of this unit has a button on it just below the LCD to enable/disable and adjust the alarm. It also has all wires exiting the rear which include transducer wires, alarm wires and alarm as well as power and ground. What is missing is the alarm set/on wires as this unit uses the button the face for that.

So my options were to replace the unit as-is (which is the only option if I chose another model) and cut out the dash panel with a round 2-1/8 hole and disconnect my dash mounted switches that operate it, relocate the unit to some other place (though not sure where I would have put it), or just give up as the factory unit is NLA and Hummingbird does not service them anymore (yes I did contact them to see if repair was an option).


So this is what I did:
I bought the ebay unit for $75.00 in hopes I could modify it and adapt it to work like mine.
I removed the dead unit from the boat.
I carefully pryed off the front cover of the old unit. It was glued on and did break a bit but not enough to cause any issues anywhere. I then pulled out the circuit board and wiring harness and set it to the side.
I then did the same on the new unit. Popped off the front round cover, pulled circuit board and wiring as well.

After all was apart, I de-soldered the front mounted switch from the new one (2 points where mounted and 2 points where contact tied to board). I then removed the wiring harness from it (just simple plugs here, no soldering).
I took the old wiring harness and plugged to new board and then soldered alarm wires directly to board in place where switch was connected before. I then re-assembled the unit and glues the flat front face from old unit onto new unit.

I then connected it up to a battery and to my surprise, everything still worked! I even touched the alarm wires together and the alarm set to On. Touched again and it went Off. Held them together and the alarm depth started changing (10ft, 9ft, ect..).

So now I have a brand new depth finder with an old front face, dash mounted rocker to turn on/off and a dash mounted rocker to set the alarm. I can even use my old Transducer since it is the exact same model

I plan on installing in the boat tomorrow, wish me luck.

I will admit that this was a serious PITA!! Now that I have done it, I probably would not recommend to anyone unless you are very brave. If it fails again, I am replacing with a standard unit and will either dash mount it or relocate somewhere else if I choose a non-dash mount model.

If someone is in the same situation as I am, there is 1 more left on ebay (it is a new unit too and does include transducer). It can be done but be warned, it is not a fun job trying to break them apart without actually breaking them. Then doing the de-soldering work is a bit nerve racking as all I could see if me throwing away the new unit after I messed up and broke it


Well, hope this helps someone at some point in time.

[ss3964spd]

Love the ingenuity! Pics would have helped us all live your hell though. LOL

[mcoffey]

Yeah, wish I would have thought of that while I was doing it
Here are some that will paint some of the picture though.

Here is what the dash looks like. You can see the small rectangle LCD on the far right.


Now here is what the new unit looked like brand new out of the box. Note the small button on the bottom on it? This is what I had to remove.


Here are all the leftover parts
This is the old housing and circuit board (with LCD attached) and the new wiring harness that I had to replace. Note that it has the alarm attached, transducer plug and then only 3 other wires which are for Ground, 12v Battery, and 12v Switched (red, yellow and black wires on far left). The other end with the red and white plugs is where it connects to the circuit board.


And finally, here it is completed. Note the new face with the 4 screw holes and no front button anymore. Also, there is now 5 wires in the harness which are the same Ground, 12v Batt, and 12v switched but also has 2 wires that will connect to a dash mounted switch to activate the alarm now. The wires are also ready to crimp on and partially heat shrunk.


Just need to mount it in the dash now and connect the wires. Then re-do the foam tape holding the dash panel on and I am all set. In bench testing it seems to work good so I am feeling good here.

[mcoffey]

Well, crappy weekend here in VA. so job not fully tested. I was able to pull the cover off long enough to re-install the depth finder, re-attach the dash panel and even re-wired my stereo to an un-used rocker switch on the dash (since i had the panel off it was easy to do). Now I do not have the stereo wired hot and the need to remember to check that is off all the time. Now I can just check all rockers and verify they are in Off position and I am set.

So back to the depth finder, it is fully installed and wired. Seems to work but since i did not put the boat in the water, can't tell if the old transducer is working or not. That is my last test and then I am done unless it does not work. I did get a new one so I can wire it up and epoxy it to the hull if I have to (was trying to avoid that if possible though).

So, operation pain in the ***** is almost complete

[footewi]

Thanks for the great idea! I found an HDR 200 missing alarm and transponder, but otherwise working. In other words, a perfect donor unit. I followed your technique, and now have a working depth sounder. Getting the plastic faceplate off without wrecking it was certainly the hard part. A few pictures attached in case anyone else wants to give it a try.

[mcoffey]

Nice work! Yes, the removal of faceplate was a bit tricky for me too. Also, the removal of the switch on the board was not too fun either.
Glad my posting helped a bit or at least gave you the hope that it could be done