I assembled the module and it worked fine. Then I connected to the dooropener (velleman) and it did not work. No beep, no relais, nothing. Only the blue and red lights work. I thought the programming had been erased or was wrong and I connected the module to the pc. I can read/write the registers but it refuses to read the cards. I have used a 1 amp psse1210. The dooropener has a max of 500ma, the circut 100ma. So it should be sufficient? Is there a common known part that might be broken? How can I check?
It happend also while testing it, but powerdown for a few seconds solved it then… But now it doesn’t.
Most likely there is a mechanical problem (bad or loose soldering, broken PCB track or pad, bad contact, etc…)
Since you can access it through a PC, the controller is most likely not damaged.
If you have a scope, or maybe a multimeter set to ‘AC’, you could check if data from the card arrives at pin 15.
This will allow you to narrow down the area where to look for a problem.
Pn 15 has a constant voltage of 3.41 V. No changes when I use a card. I checked the antenna coil, no broken circuit there. Will try to look to the pcb, but under a magnifier I can’t find broken connections or shortcuts. Difficult to see anyway because of the green layer. If I should be able to see a v change then a broken diode of lm would be the most logical. Unfortunately I don’t have a scope.