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GNS 430 Sticky Button Repair

txshan130

Well Known Member
For those of you with "old" GNS430 or similar units...

For the last several years, my front faceplate buttons have been getting more and more unreliable. Seems like every time I went to fly it took more and more presses to activate the buttons. After checking on Garmin's repair prices, I decided I was up to the task of doing it myself :)

For most of us here, this would be an easy task...so here are some pics to help others make the decision which way to go! FYI, my 430 is at least 10 years old, if not a bit older.

I used DEOXIT (available at ur local Radio Shack) on the PCB and on the underside of each switch...

Hints on disassembly from BarranAir (post below):

- To remove the ribbon from the back of the display screen, gently push up the tabs on the ends of the little plastic cover on the connector until it pivots up and the ribbon will spring free. To reassemble, make sure that the plastic cover is pivoted open, then slide the ribbon into the slot underneath until it butts on the end then pivot the cover to the flat position over the ribbon and slide the cover down on the connector to clamp the ribbon. Give a gentle tug on the ribbon to make sure it is clamped by the plastic cover.

- To remove the knobs, use a medium sized flat screwdriver to push the buttons off one at a time. They are just held in by friction. Take care to exert pressure as evenly as possible so the button doesn't get cocked. Suggest twist the screwdriver alternately on opposite sides of the button. When it has moved a few millimeters, you can pull it off with your fingers.

- To remove the knob components, you will need to unfold the GNS into the two components, NAV and COM, as shown in the PICS. This will expose the other ends of the ribbons and give you easy access to pulling the connectors out. Take care, of course, not to damage or bend the delicate pins. Once the ends are separated from the mother boards, you can unscrew the knobs in the face plate. The large hex nut (about 1/2 inch) holding down each of the two big knobs are difficult to fit with a socket ... I used needle-nosed pliers to grab opposite flats on the nut and twisted it off, one flat at a time, until I could unscrew it with my finger.

Overall, not too difficult. I recommend doing this on a comfortable work bench or table with lots of bright lighting. It is important to see small movement of screws and fasteners to know if you are making the right moves, else you might end up forcing something.


After putting it all back together, the switches all work like new again...very happy to have saved lots of money and time!

Excellent Pics from Barran Air here:
https://1drv.ms/f/s!AnnmZEt4LXEIheoQFK6MFkbqBQHuDw




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I'd really like to do this repair! Could you tell me more about how you did it?

I was intimidated as soon as I loosened the CDU Assembly and saw all those paper-thin ribbon cables and how little room there was to work on disconnecting them. Any tips?

Some of the ribbon cables seem to be soldered on to the backs of the concentric rotary switches--did you disconnect them? How?

How did you take those concentric rotary switches out?

How did you get the LCD out?

How does the front plastic (with the buttons and printing on it) come off?

Finally, how do the little metal dome switches come off the PCB and how do you re-attach them?
 
I did this as well a few months ago after my enter button pretty much quit. Now its as good as new. Peeling up the plastic cover was a little nerve racking, but the DeOxit really made quick work of all of this.

I work in an engineering department, so I borrowed a 12v power supply and was able to rig up the unit in Test mode so I could bench test it after i was done with surgery. I would have hated driving 45 minutes to the hangar, only to find that i screwed something up.
 
So I'm having this exact issue on my 430 that was upgraded to a 430W in 2017, it's a 2007 unit originally. I'd really appreciate if anyone could give some detail on how to get the face plate off, it's not immediately apparent and I don't want to damage the unit. I've tugged on some things as hard as I dare and nothing has budged.
 
Maybe post some pics as to what stage you are at... It's been a long time since I did it so I probably won't be much of a help anymore. Hopefully some other guys chime in with more recent info.



QUOTE=BMC_Dave;1266858]So I'm having this exact issue on my 430 that was upgraded to a 430W in 2017, it's a 2007 unit originally. I'd really appreciate if anyone could give some detail on how to get the face plate off, it's not immediately apparent and I don't want to damage the unit. I've tugged on some things as hard as I dare and nothing has budged.[/QUOTE]
 
GNS 430 Repair Manual on line

I googled "Garmin GNS 430 Button Repair" and, in the list, found a link to the repair/maintenance manual ------ it gives some drawings and instruction for removing and replacing components ----- I did not read in detail, but it might be what you need --- (my 430 is starting to get sticky buttons)

Ron
 
Steely Eyed Missile Man

Brian,
You Sir, are a Steely Eyed Missile Man! I would never consider tearing into my 430 like that and I'm a Navy trained electronics technician! The big knob on the left side of my 430 just quit working and I returned it to Garmin for repair. They will charge me a fortune! Glad it worked out for you. Nice work!
Randy
 
The CMM didn't seem to have any useful information regarding the removal of the face plate. Since it was upgraded in May of 2017 I emailed Garmin asking if this unit was still under warranty, that's the obvious preferred choice. I'll wait to hear back from them, but I'm pessimistic.

I've not had anything apart, aside from removing the dials.
 
king kx-155

This is great. I'd like to do this to the push buttons on my King KX-155 NavCom. Might you know how to open it so I can access it with DyOxy5?

thanks
 
$1200 Flat Rate

The big left knob quit working properly. I couldn't dial the most significant digits accurately. So I reluctantly gave my 430W to my local avionics shop for processing. Garmin would not take it directly from me so I had to work through an authorized dealer.

I got it back today. The repair description says Garmin replaced the faulty knob, checked, aligned, updated, blah, blah, blah, and $1200 dollars later I get my 430W back with a BRAND NEW KNOB.

Kudos to my local avionics shop, Mac Avionics at KLAL. They didn't charge me a penny for their labor / support. But, with shipping, the total was $1250 bucks. REALLY? For replacing a knob?

I like Garmin products, I really do. But, their business model is obviously focused on those for whom money is not an object. I think I'll focus MY future avionics business model and dollars on companies for whom VALUE for the owner is an object. I'll also look for those companies that understand the owner / operator equation and especially the EXPERIMENTAL owner / operator. I could care less about all that paper they gave me with the repair! I just wanted it fixed.

To their credit, they did get it back in less than 10 days. Replacing a knob apparently takes that long . . .
 
Maybe post some pics as to what stage you are at... It's been a long time since I did it so I probably won't be much of a help anymore. Hopefully some other guys chime in with more recent info.

QUOTE=BMC_Dave;1266858]So I'm having this exact issue on my 430 that was upgraded to a 430W in 2017, it's a 2007 unit originally. I'd really appreciate if anyone could give some detail on how to get the face plate off, it's not immediately apparent and I don't want to damage the unit. I've tugged on some things as hard as I dare and nothing has budged.
[/QUOTE]

Hi Guys,

HERE ARE SOME PICS: See Link below:

I have started tackling this on my Cirrus which is also getting long in the tooth; it is now 18 years old. I have dismantled most of the major components in the two GNS 430s with the two objectives of cleaning the sticky buttons and also of replacing the battery.

DISMANTLING:
Couple of hints:

- To remove the ribbon from the back of the display screen, gently push up the tabs on the ends of the little plastic cover on the connector until it pivots up and the ribbon will spring free. To reassemble, make sure that the plastic cover is pivoted open, then slide the ribbon into the slot underneath until it butts on the end then pivot the cover to the flat position over the ribbon and slide the cover down on the connector to clamp the ribbon. Give a gentle tug on the ribbon to make sure it is clamped by the plastic cover.

- To remove the knobs, use a medium sized flat screwdriver to push the buttons off one at a time. They are just held in by friction. Take care to exert pressure as evenly as possible so the button doesn't get cocked. Suggest twist the screwdriver alternately on opposite sides of the button. When it has moved a few millimeters, you can pull it off with your fingers.

- To remove the knob components, you will need to unfold the GNS into the two components, NAV and COM, as shown in the PICS. This will expose the other ends of the ribbons and give you easy access to pulling the connectors out. Take care, of course, not to damage or bend the delicate pins. Once the ends are separated from the mother boards, you can unscrew the knobs in the face plate. The large hex nut (about 1/2 inch) holding down each of the two big knobs are difficult to fit with a socket ... I used needle-nosed pliers to grab opposite flats on the nut and twisted it off, one flat at a time, until I could unscrew it with my finger.

Overall, not too difficult. I recommend doing this on a comfortable work bench or table with lots of bright lighting. It is important to see small movement of screws and fasteners to know if you are making the right moves, else you might end up forcing something.

CLEANING:
I have sprayed the tops of the metal snap caps with an electrical contact cleaner. I can't figure out how to get the caps off so sprayed sideways hoping to get under them. I did the first one yesterday and re-assembled the unit and put it back into the panel and it started up.

Whew!

However, while each button operation is generally improved, one of them is still majorly sticky. I will re-do this in the second stage of this project when I am replacing the battery. I think the problem is that the cleaning agent didn't get into the contact area because it is covered by the metal snap caps.

If someone can help me with how to expose the contacts underneath, I would really appreciate it.

BATTERY REPLACEMENT:
I am at the stage of waiting for my new batteries to be delivered and I am preparing to de-solder the old battery. I have not yet removed the mother board as I want to keep the two projects separate. But I have exposed the batteries above the mother board as you can see in the PICs. I have to remove the motherboard and expose the battery terminals and de-solder them. Never done this before but will practise on a scrap circuit board when all the de-soldering equipment arrives. I have my ESD wrist bracelet ready for that operation.


PICS Here:
https://1drv.ms/f/s!AnnmZEt4LXEIheoQFK6MFkbqBQHuDw
 
BarranAir -

Thx for adding the hints! I will move them to the top if I can...

First of all, please make sure you use Deoxit and nothing else...that is important.

I looked at your pictures and it's not evident that you finished taking it all the way apart - Did you get it to the point where you're looking at the PC board with the snap caps (see my pictures on first post)? If so, all you need to do is peel off the top part - the caps are held on with clear packing tape.

Get some new clear packing tape to use when you put them back on. I am pretty sure that spraying them without removing the tape will not be very effective.
 
Hi Brian,
No I did not take the tape off; it was practically invisible and didn?t seem to be what was holding down the caps on the micro switches. Thanks for pointing me in the right direction.
I will reopen the units, one at a time, in a couple of weeks. DeOxIt to be delivered, then I am diving in.
Wish me good luck with the buttons and with the battery replacement.
Cheers.
 
How did you spray some switches?

Can anybody provide details on how you applied the contact cleaner to the metal dome switches? On my 430 they are protected (held in place?) by a thin clear film so spraying will not get inside the dome switches where the electrical connection takes place. I could peel the film off but I suspect it holds the switches since they do not appear to be soldered to the PCB. Thanks.
 
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Hi - they are held in place by clear tape, much like packing tape. I removed all of them, along with the tape and used qtips and the Deoxit to clean off any oxidation. Then I used clear packing tape, and an x-acto blade to put them all back in place.


UOTE=FloridaMan;1461782]Can anybody provide details on how you applied the contact cleaner to the metal dome switches? On my 430 they are protected (held in place?) by a thin clear film so spraying will not get inside the dome switches where the electrical connection takes place. I could peel the film off but I suspect it holds the switches since they do not appear to be soldered to the PCB. Thanks.[/QUOTE]
 
Quick question for those of you who have done this repair already. I'm in the middle of doing it now, and am wondering two things:
- When I was removing the screws from the unit housing, I noticed what looked like a bit of red thread lock coming off? Did others apply thread lock when they put it back together? And if so, and assuming you're using Loctite, assume you used the blue stuff and not the red?
- For folks who've done this previously, any issues with packing tape coming unstuck (especially during the summer) over time? The pressure-sensitive surface mount tape manufacturers use on these PCBs tends to adhere to the PCB a bit better and have more tack than regular packing tape.
 
I did not use Loctite when putting back together although blue Loctite would be fine...

My initial "repair" was accomplished over 3 years ago if I recall correctly. Just recently had 1 button having issues due to the tape not sticking properly. Having done the repair before, it was a pretty quick job to fix this time. I'm sure you could find some "stickier" tape if you looked around. I just used what I had on hand at the time which was cheap packing tape...




QUOTE=mattmo10587;1475038]Quick question for those of you who have done this repair already. I'm in the middle of doing it now, and am wondering two things:
- When I was removing the screws from the unit housing, I noticed what looked like a bit of red thread lock coming off? Did others apply thread lock when they put it back together? And if so, and assuming you're using Loctite, assume you used the blue stuff and not the red?
- For folks who've done this previously, any issues with packing tape coming unstuck (especially during the summer) over time? The pressure-sensitive surface mount tape manufacturers use on these PCBs tends to adhere to the PCB a bit better and have more tack than regular packing tape.[/QUOTE]
 
Not to be the rainmaker here, but you should realize that opening a TSO approved radio without the appropriate FAA Avionics Repair Station authority means that the unit is no longer TSO approved. FAA policy says that you have to remove the TSO identification and that it no longer legally meets the IFR navigator requirements.

Even though you are using it in an experimental aircraft, it is still an FAA approved product.

Just saying if you don’t remove the TSO tag, it is an illegal repair and it is being published for the world to see.
 
Good point Dan!

Thanks for the heads up. Guess Garmin will be the winner here. Another thread about to disappear due to litigation worries...

QUOTE=RVDan;1475201]Not to be the rainmaker here, but you should realize that opening a TSO approved radio without the appropriate FAA Avionics Repair Station authority means that the unit is no longer TSO approved. FAA policy says that you have to remove the TSO identification and that it no longer legally meets the IFR navigator requirements.

Even though you are using it in an experimental aircraft, it is still an FAA approved product.

Just saying if you don’t remove the TSO tag, it is an illegal repair and it is being published for the world to see.[/QUOTE]
 
Not to be the rainmaker here, but you should realize that opening a TSO approved radio without the appropriate FAA Avionics Repair Station authority means that the unit is no longer TSO approved. FAA policy says that you have to remove the TSO identification and that it no longer legally meets the IFR navigator requirements.

Even though you are using it in an experimental aircraft, it is still an FAA approved product.

Just saying if you don’t remove the TSO tag, it is an illegal repair and it is being published for the world to see.

It would be most helpful if you would quote the regulatory reference to back up this statement.
 
It would be most helpful if you would quote the regulatory reference to back up this statement.

The full regulatory path with detailed citations will take me a couple of days. I work with these rules every day. The short version is that a TSO article is certified under part 21 subpart O and falls under 14CFR part 43. While part 43 is not applicable to experimental homebuilt airplanes, it is applicable to a TSO article. Under part 43 only certain persons are authorized to repair avionics which happens to be repair stations under part 145 with the appropriate authorizations (Radio). If you open the radio you have performed an unauthorized activity under part 43. When you return it to service by reinstalling in an aircraft, part 43 is violated. Also since the repaired article was improperly repaired (not done by an authorized entity) it is not longer in compliance with the TSO authorization and under part 45, the markings are no longer in compliance.

So the question remains, the airplane is in experimental and if you remove the markings can you still use the radio. Yes, for VFR where there are no specific requrements, but for IFR a TSO approved GPS is required.

Let me know if you want the exact citations and I’ll dig them up.
 
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Well then I guess it's a good thing I only fly my experimental aircraft under VFR 😀


QUOTE=RVDan;1475438]The full regulatory path with detailed citations will take me a couple of days. I work with these rules every day. The short version is that a TSO article is certified under part 21 subpart O and falls under 14CFR part 43. While part 43 is not applicable to experimental homebuilt airplanes, it is applicable to a TSO article. Under part 43 only certain persons are authorized to repair avionics which happens to be repair stations under part 145 with the appropriate authorizations (Radio). If you open the radio you have performed an unauthorized activity under part 43. When you return it to service by reinstalling in an aircraft, part 43 is violated. Also since the repaired article was improperly repaired (not done by an authorized entity) it is not longer in compliance with the TSO authorization and under part 45, the markings are no longer in compliance.

So the question remains, the airplane is in experimental and if you remove the markings can you still use the radio. Yes, for VFR where there are no specific requrements, but for IFR a TSO approved GPS is required.

Let me know if you want the exact citations and I’ll dig them up.[/QUOTE]
 
for IFR a TSO approved GPS is required.

Thanks for that summary.

There's one small interpretation which many here (and at least one experimental avionics vendor) believe can be applied, and it's an important one. For amateur-built aircraft one's navigator doesn't need to be certified under a TSO, it just needs to provide performance equivalent to the TSO-mandated performance. This has been discussed at length in these forums. A GPS which has undergone a minor repair to something as simple as a front panel switch is unlikely to have suffered a material change in navigation performance.

ELT's, on the other hand, don't benefit from this same "equivalent performance" dispensation - a TSO'd device is required, period.
 
Thanks for that summary.

There's one small interpretation which many here (and at least one experimental avionics vendor) believe can be applied, and it's an important one. For amateur-built aircraft one's navigator doesn't need to be certified under a TSO, it just needs to provide performance equivalent to the TSO-mandated performance. This has been discussed at length in these forums. A GPS which has undergone a minor repair to something as simple as a front panel switch is unlikely to have suffered a material change in navigation performance.

ELT's, on the other hand, don't benefit from this same "equivalent performance" dispensation - a TSO'd device is required, period.

I have no do in the fight so to speak, I was just concerned that if the FAA took issue it could be problematic for some.
 
So the question remains, the airplane is in experimental and if you remove the markings can you still use the radio. Yes, for VFR where there are no specific requrements, but for IFR a TSO approved GPS is required.

That sounds like an interpretation of the rules and not specific language from the rules.

As we have learned from the ADSB GPS antenna happenings of the last few years, we need products that meet the perfromance specifications of the TSO, possibly with proof of that, and not necessarily have the certification. Opening the case to clean oxidation from buttons is not likely to change the fact that the units performance meets the specificatoin. We know that it did prior to opening it.

Larry
 
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Irony in the fact you need to fix oxidation on a TSO'ed product that is tested for this.

TSO means nothing to me, what is more important is that Garmin's product scale is large enough to find these issues and weed them out so the reliability exceeds any arbitrary government standard.

Deoxit is a fantastic product BTW.
 
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