GPSrChive Discussion Forum

Hello,
I recently acquired a GPSmap 60CSx at a good price. After cleaning it up, I had a couple of months of use, really liking the display and the receiver accuracy. The unit was acquired in the USA.

A couple of weeks ago, back in Scotland, I find that the unit was behaving oddly. Initially I thought it was related to the maps, since it only had a US south west topo map loaded on the SD card. I swapped the maps for routable OSM and set it in a good position to "soak" and figure out where satellites are.

Current situation is that the buttons have stopped working. All buttons will make it beep (i.e. they are making contact), and occasionally the Page button will cycle. I am able to press Page and Ent on start to get the reset dialogue, but I am then unable to navigate to reset the device.

I have dismantled the unit, and cleaned out battery corrosion material which had managed to make it into the unit at some point. There is some corrosion between layers on the kapton button layer, but it does not look like it has broken any traces, and I believe it is only on the circuit for the backlight LEDs. I can see that there are many test pads under the button layer, but I have been unable to find a service manual to make them useful.

I have exhausted my limited skills, and wonder if anyone here has any thoughts.

Cheers,
Tobias

Hi Tobias, you probably have another GPS now. The fault button thing is pretty terminal in my experience of fixing and keeping this model working for trampers and pest control contractors - lately with 3D printed parts I got made to replace the top cap and internal frame.

Only one of about a dozen such faults over the years was able to be fixed - I saw corrosion on the board at the edge of the flat metal cover so lifted the cover after melting the solder and cleaned the corrosion away with isopropyl alcohol on a cotton bud. It worked.

This is the answer I received from ChatGpt

The problem is most likely caused by the keypad membrane (button foil) — damaged or corroded due to battery leakage.

1. What we already know

The buttons still make confirmation beeps, which means the microcontroller detects a short, but the signals are not consistent.
The Page button works only occasionally — indicating partial breaks in the conductive traces.
The reset menu appears with Page + ENT, but navigation is impossible — keypad signals are missing.
Corrosion from leaking batteries has reached inside and probably damaged the membrane.

2. Most common causes

Damaged keypad foil (membrane) — broken or corroded conductive traces.
Dirty or oxidized connector between the keypad membrane and main PCB.
Corrosion under the controller IC that reads the button matrix (less common but possible).

3. What to try

Thorough cleaning
Use 99% isopropyl alcohol (IPA) with a soft brush or lint-free cloth to clean the connector and contacts.
Inspect with a magnifier for green/blue corrosion deposits.
Check continuity of traces
With a multimeter in continuity mode, test the button lines from the test pads.
If a trace is broken, you can repair it with conductive paint/lacquer (e.g., CircuitWorks).
Connector re-seating
Sometimes pressing or reseating the ribbon cable connector restores proper contact.
Replace the keypad membrane
If many buttons are dead, the best solution is replacing the entire keypad membrane. Replacements are still available on eBay/Aliexpress (~15–25 USD).
If damage is deeper
If battery leakage reached under the keypad controller IC, the PCB may need professional SMD repair.

4. First steps to take

Disassemble and clean everything again with IPA.
Check a few traces with a multimeter.
If just one or two lines are broken → try conductive paint repair.
If most buttons don’t work → replace the membrane.

Summary:

The issue is almost certainly with the keypad membrane — corroded or broken inside. Cleaning may give a short-term improvement, but if corrosion spread between layers, only a replacement membrane will solve the problem reliably.

Link to the new keyboard

https://www.ebay.com/itm/127157879789

Never rely on ChatGPT answers!
There is no separate keypad membrane, the contacts are on the mainboard. Also, the problem is not the rubbery keypad. It doesn't contain contacts at all, it just connects the contacts on the mainboard so replacing it doesn't help.
The problem may not even be caused by corroded contacts itself, but by corroded traces on the mainboard. Not very visible on the photo, but the traces at the bottom are corroded on this GPSMAP 60Cx mainboard. (Also, two of the contacts are slightly corroded)

Spoiler

IMG_5899.jpg