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key fob repair / cleaning / re-conditioning

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i found this on legacyGT.com for a 99 outback key fob. (alpine 99 - 04)


i would probably add a little WD40 to the drying process.

it can't hurt.





This repair applies to the key fobs supplied for the Alpine security
system used in Outbacks and Legacys from 1999 to 2004, but I'm posting
here because ours is a 99. It may work on non Alpine fobs. It may not
work on your Alpine fobs. But it's something to try on a fob that may
otherwise need to be discarded.



I found a third fob that only functioned when
it wanted, so I decided to do the same repair/de-corroding as described
above. Except this time I took pictures.

1. Take the fob completely apart. You'll need a jewelers sized
Phillips to remove the three small screws that hold in the circuit


Make absolutely sure that you remove the battery. If you use this
de-corrosion method with a battery installed you will actually make
corrosion, and could eat away and possibly destroy the smaller
electrical conductors.

Of the three fobs I've de-corroded one had corrosion on the pins of both ICs on the back of the board.


Two of the fobs had corrosion inside of the push button switches on the
front of the circuit board. The switches are the two identical square
metal items mounted at a 45 degree angle with a round "button" in the


I used Lime Away as a readily available acid that is also fairly safe.
Even so I made my acid solution by diluting it about 50/50 with warm tap


Next I placed the circuit board in a small glass dish of the acid
solution and watched for a reaction with the corrosion, which is a
stream of fine bubbles. This board had no corrosion to speak of on the
back, but the following picture shows the front with bubbles coming out
of the push button switches and a bit of foamy froth floating on the top
of the acid solution.


Because the acid is consumed by the corrosion as it is eliminated you
have to agitate the solution every 5-10 minutes or so. This is to make
sure there is fresh acid at the site of the corrosion. I used my index
finger to shake the circuit board for about 5 seconds, with a quick tap
water rinse after the agitation. (Rinse the finger, not the circuit

I soak the circuit boards until the foaming stops, which was about 20 minutes for this particular circuit board.

After the acid I soak the board in warm tap water to wash out any
remaining acid. I soak for at least 60 minutes and agitate every 10-15
minutes. (I don't use a base, like baking soda, to neutralize the acid
because the base and acid reaction will form a salt. I'd rather use
lots of water to flush the acid out and sidestep the hole issue of
needing to wash out some kind of salt.)

Next step is drying. I used canned air to blow the obvious moisture
away, followed by air drying for a couple of hours in a warm, dry place.
If you don't have canned air then shake it off and leave it overnight
in a warm dry spot.

When dry just put the thing back together. Cross your fingers and see if your fob works again.


Edited by johnceggleston
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