Infra-red remote-control not working.

["F.Th.A.Hartendorp" <hartend@domain.elided>]

Hi fellow-digesti,


My name is Frank, from The Netherlands, although "lurking" for the last two
years on this magnificent message-board never posted before.
Never had the audacity to, or the need to do so, until now.
I love to read your posts but you guys write that much I didn't get the time
to write. ;-)
A sorry excuse, I know, but could someone please help me on this one?

What happened.
Last week I tried to open the doors with the RC, but no joy...
First I thought of a flat battery, our kids playing with the interior
light-switch, again.
So I used the key to open the door, everything else worked, besides that
darn remote control!
Might be important to know that only(!) the key-operated door (un)locked.
Normally they all open/close simultaneously as by the RC or switch between
the front seats.
The RC-indicator LED worked and later the IR-LED also found to be
transmitting some code.
(Easy check is to hold the RC in front of your web-cam. Your eyes won't see
the infra-red, but your web-cam is!)  :-)

What I did already.
I replaced the little battery's in the RC to be sure, still no joy.
As soon as I had some spare time, I checked the most obvious things.
The wires in the front-doors, relays , fuses and the "relay/computer" under
the dash have been checked.(glove-compartment)
I even checked the components inside that box and found them to be fine. (2
transistors, 2 relays, 2 diodes and some resistors, nothing fancy to speak
off.)
Which made me conclude there was some more electrickery to search for.
I found the receivercomputer in the courtesy light unit with a
indicator-LED, a infra-red transistors and a little push-button.
It seemed to me that this little push-button is to program some sort of a
programmable device inside this circuitry, but how?
What sequence must I follow, to make it do what it's ought to do?
For the time being I left it alone and began a search on the internet, there
is more to be known for a successful attack on this one.

What did I find?
In the archives of Alfa-digest I found that for my '95 model their is a need
for a 4 digit unlock-code to access this device.
(see Technical Service Bulletin 40.95.01)
This unlock-code should have been provided by the former owner with the
documents for the car, but.... it got lost.
Ouch, found a quote on this device: "If you ain't got it then it's time to
buy a new receiver (200ishGBP)"
In the RC-transmitter I found a 4 digit-number, is this the code transmitted
by the RC? (That would be one hurdle taken already)
But how can I obtain the unlock-code for the receiver or reset it to a known
default unlock-code without a large payment to AR SpA?
Has anyone "hacked" this device ones before? Or maybe, could this code be
retrieved from a AR-dealer or the factory?
They do keep records of such things, I hope?


 If nothings comes up I'm very tempted to try myself, take the receiver out
and will look how this 30 dollar worth of electronics can be "hacked".
How else can this to be explained to my BW?


Thanks,
for your input and many smiles in your Alfa's,



Frank
(Still smiling, but a little frustrated by some electronics)


--
F.Th.A. Hartendorp
The Haque, The Netherlands.

'86 33 (long gone and forgotten.)
'91 75 1.8E Indy (hit in the rear and sold her...
 love to have one again with V6 3.0 engine.)
'95 164 2.0 Super (still troubles to solve...)

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