Garmin 4000 series Power Plug Repair

[fractalphreak]

Good weekend all!

I've been stuck doing schoolwork and workwork for the past two weekends, and will be doing schoolwork the rest of this weekend, SOOOOO...to keep from going crazy not out working on or enjoying the boat, I spent some quality time tonight with one of my chartplotters. I realize these are older, but they work and Garmin is still (crossed fingers) putting out legacy GPSMAP updates.

I thought I'd post this because there seems to be a market for the part I bought, so others might have had the same problem.

We have two Garmin 4212's, one mounted at the lower helm and the other for the flybridge. Our bridge has a bimini but no enclosure; our PO did and we continue to store the bridge 4212 locked up in the dry salon when the boat is at the marina. At some point, the power connector on the back has gotten broken - the power cord would still plug in but it would work its way loose and then loose power.




While randomly browsing for 4000-series parts, I found these on ebay. The seller had an offer to do the install for $200. I had never bothered even checking with Garmin on their cost, but bought the part. These units are old and way out of warranty. I worked in electronics assembly in high school, and can solder a bit so I bought it. I later found the same company also sells the connector with a pigtail attached, but that too has to be soldered, this time to a circuit board. I don't think that is any easier or harder.



The first step was to remove 16 screws around the case. The case is sealed with a rubber gasket which thankfully stayed in place the entire time on one half of the case and didn't stick to the other side.



After the screws were out, the case opened up easily. There are a total of three wire harnesses attaching the back of the case to the main body.



The two with larger wires simply unplug - they don't have captive clips, just a pressure fit. I took photos of them as I removed them, but the connectors only go together one way, and the two harnesses have slightly different connectors so no mixing them up.





The wire harness on the left of this picture is very thin fragile wires. The connector in this case is also a pressure fit, and very thin. They have secured it with green transparent tape that seems to be scotch-type tape.





I carefully peeled it back....



and pulled the connector right out...



...this separated the two halves of the MPD, allowing me to get to the back half to work on the power connector. More in the next post so I can add pics of that part of the process.

 

[fractalphreak]

Part 2

There is a circuit board mounted in the back half of the MFD. To gain access to the power wires/connector you need to dismount it from the case. There are 7 screws to remove:






Then remove the plastic nut holding the power connector on the back of the MFD. It is not very tight, its sealed inside with an o-ring and its a pretty thin plastic nut.



Now you can carefully move the circuit board up and out of the way. As you do, you'll have to feed the connector through the hole in the back....





Here we can see the two power wires are secured to the connector and covered with heat shrink. We already know this type of power connector is a solder connection, so that's what's under there. You can see there is a black tube which looks like a noise filter over the two wires and secured to the corner of the circuit board with a black zip tie. I was able to carefully slip the noise filter out from the zip tie, and pulled the plug out to get a better look.



After removing the heat shrink, I'm ready for the soldering iron.



Here's what I thought I would need for the job from this point on:



From left to right: solder wick, iron with base and damp sponge, new part, rosin core solder, and a new black zip tie. (I ended up not needing the zip tie, I was able to slip the power wire/noise filter back into the old one and even got it just a tad tighter.)

...on to part three for some desoldering, wire prep, solder, and put it all back together!

Off to catch some z's and will put the rest of the project up later, but don't worry, it turns out okay!

 

[fractalphreak]

Part 3

This type of connector has external pins and internal tubes/barrels. By that I mean there are pins that the power plug connects to, and little tubes that the internal wires are inserted into and then soldered into place.

To remove them, its necessary to heat the tube/solder joint while putting gentle pressure pulling the wire from the plug. In this case Garmin has used some pretty beefy wires (12 awg) to go from this connector to the board.

I had initially thought that simply using the solder wick would be the best to remove the wires, but rethought it - the wick is a good gentle solution and really minimizes the heat transfer to delicate parts AND gets old solder out of the way. In this case I was trying to remove beefy wires with a lot of solder down in the tubes of the connecter. I just used a high heat setting, and actually ADDED a little fresh solder to help with heat transfer. It worked really well. I did use a little of the solder wick to see if I could clean up/prep the wire ends to resolder them, but decided just to cut the wire back, strip, and tin new ends. There was enough wire available for this - I only actually cut just under 1/4" off the ends.



I discovered the part I bought was just a hair too small for the wire. I took a close look at whether I needed to stop and resource. The Garmin draws 4 amps, and my internal power wires from the plug to the board are 12 awg (measured approx .080). This MFD is mounted on the flybridge and gets its power from a circuit breaker mounted in the overhead right above the lower helm station. Its an approximate 10-12 ft wiring run from the breaker to the MFD, which puts me at a required 16 awg for up to 5 amps at 15 feet. I decided to see what size the wire would have to be to reliably get it inside the tubes; I ended up trimming about 8-10 strands from each wire. Afterwards they measured .070 to .071 and fit the tubes of the connector just fine. There was no part number/marking on the connector, I'm thinking that its a like/same but is made for metric wire - 2.5 mm2 wire is supposed to be .70ish. In the end I decided to stick with my trimmed wires due to them still be so far oversized. I tinned the ends of the wires with solder.

I didn't take a photo, but before desoldering I marked the old connector with a + and - where the respective wires were. The connectors did not have a common reference on the back for polarity, the only thing to rely on was the detent on the recess where the plug goes into the connector.



I turned the connector over to identify where the positive is in relation to the detent mark.



Then started off in the same position with the new part...



...and marked the new part the same way. (I double checked this like 10 times!)



Soldering was quick and easy - using my alligator clip stand to hold the wires, I put the connector on the wires and applied solder. (This process was probably 15-20 seconds total and was almost a letdown after tediously cutting out a few strands at a time to get the wires trimmed down!)



A little hot air and the heat shrink was done!



I was able to reuse the black zip tie to hold the noise suppressor back in the same position on the board. They had left enough of an ear I got ahold of it with needle nose pliers and got another 1 or 2 clicks on it and made sure it was snug.



The case has a recess for the oring to seal into - much easier to put the oring around the connector first to assemble.



This ended up being a two handed operation - one hand feeding the connector through, the other pulling it through. Once I had it through I need to keep a hand on the back so it wouldn't pull back out of the hole while I put the retaining nut on.



Almost done!

 

[fractalphreak]

All that is left is to reconnect the internal wire harnesses and close the case up...First up is the fine wires.



And carefully retape - I didn't have any of this tape. I looked it up and its likely an ESD tape, they needed tape to assemble this MFD and needed something that wouldn't attract or create static.





Back secure. The adhesive is remarkable - it was not hardened or blotchy, I was able to carefully peel it back, and went back together with very firm adhesion. And its right about 10 years old!



I attached the other two wire harnesses....



...and put the 16 screws back in the case. DONE!



My little debris pile. No leftover parts!



I normally would not be repairing my electronics. This particular project was to keep a working decent display working consistently for the next few years without the problem of coming unplugged all the time. It was well within my capability, and for anyone with some previous soldering experience not very difficult. I took a lot of pictures hoping that at some point down the road someone is able to search the forum for replacing a power connector on one of these Garmin's and is able to see if its something they can do too.

Happy weekend!

 

[High Wire]

Nicely done

 

[Bacchus]

Nicely done [emoji736]

Yes... I agree.
It's nice to have an idea of what to expect before tearing something like this apart.
Photos and write up are excellent.

 

[fractalphreak]

Yes... I agree.
It's nice to have an idea of what to expect before tearing something like this apart.
Photos and write up are excellent.

Thank you both! I can't tell you how many write ups and threads I've poured over and USED in the past year - it doesn't make sense to NOT offer something back to the community.