Central lock car key repair

[R_J]

Re: Central lock car key

It is still hard to see where the traces go.
sw3 and sw4 have a common connection at the C6 point
sw4 goes to D2 (a); sw3 goes to D2 (k) but where do those lines go after that?
sw1 and sw2 have a common point also which connects to the sw3 & sw4 common point
sw1 connects to D1 (k) and U1 pin5
Does sw2 connect to U1 pin 3 or 4? I can't follow it under the ic
Are D1 and D2 connected to each at their anode or cathodes?

And last where does U1 pin 8 connect? does it connect to the common point of the switches?
I still can't see how U1 gets its 12 volts to operate. I suspect it detects a button push then draws current through the led for its vdd voltage which in turn lights the led.

[R_J]

Re: Central lock car key

The transistor should not be shorted, but that is just the rf amplifier, If it is shorted, it can be removed and the ic,led etc should still work. this is the pdf of the transistor.
Here is a basic diagram for a one button remote

[Morsus]

Re: Central lock car key

If I remove the transistor should I jumper connect the remaining contacts?

[R_J]

Re: Central lock car key

I don't understand, what contacts are you talking about?
If you remove the transistor You can check and see if itis shorted or if something else on the board is shorted.
The ic/tranmiter would work without the transistor but the working range would be about a foot if that.