New Spare Key W211 3 Button (NEC chip) Options Where to Buy ?

[pmcgsmurf]

Hi folks

The daily used key on the old W211 has failed.

Starts car ok, RF does not work for Lock/Unlock though.

After testing key I can see that the IR LED on top side PCB (shown side) is triggering all the time.
Thought this may have been a low resistance on one of the switches but sill the same after removing these, cleaned and checked PCB but can't see any obvious problems.




What's cheapest source for a key, can I get a blank and program in Star (not looked yet)?

Anyone any old ones laying around, thinking I could maybe swap the chips across or even do some tests between a good one and mine to trace fault?

Is it possible to upgrade to the chrome key?

 

[55AMGCLK]

In response to “Is it possible to upgrade to the chrome key?”:

I ordered a new car for my car a couple of months and the new one was the chrome key.

The old key I have is the same as the pic you posted.

 

[pmcgsmurf]

In response to “Is it possible to upgrade to the chrome key?”:

I ordered a new car for my car a couple of months and the new one was the chrome key.

The old key I have is the same as the pic you posted.

Thanks, should be possible then.

Thinking about it I have chrome keys on the E55, not sure if these were standard or an upgrade @Alps

 

[Alps]

They came with my E55 Pat.

You can buy the outer shells, plenty of aftermarket ones on Alibaba or Ebay

 

[pmcgsmurf]

They came with my E55 Pat.

You can buy the outer shells, plenty of aftermarket ones on Alibaba or Ebay

Thanks, think I can buy one and swap the NEC chip over, worth a go if I can't get an old one.

 

[pmcgsmurf]

There are a few keys on ebay for around £21 that list NEC so I might take the chance and buy one and swap the chips over.

Thing is you then worry that £20 here, £20 there will soon add up to more than it should.

 

[pmcgsmurf]

I've been examining the old key, as I mentioned the IR transmitter is triggering all the time.
Non of the tact switches are short, have removed all these and cleaned PCB.

On measuring the resistance from the tact switch points to ground I get around 260 KOhm on each.
On a good key this is in the 40 MOhm range.

Lifting the pins on the chip shows that it is the chip to ground that has this low resistance.

Need another key now to swap the NEC chip over.

 

[55AMGCLK]

MERCEDES 3 BUTTON SMART REMOTE CAR -van KEY FOB | eBay

Maybe worth a punt at just under a tenner.

 

[pmcgsmurf]

Thanks, I'll get one ordered to play with

 

[pmcgsmurf]

Sorted now.

Got a replacement PCB from en ebay seller for just short of £20, tested the RF & IR on this working ok.
Removed the NEC processor from my broken key.



Fitted this to the replacement PCB I got and also got a new shell for it too for £6 on ebay.



Tested and all working ok so quite pleased it only cost me £25 and I now once again have a spare key.

So it would seem that the RF front end chip on my key was faulty.

Worth considering swapping the NEC chip to a known good PCB for anyone with a broken key, thread updated in case it helps anyone in future.