I am having problems with the 125kHz RFID module as well (ELB149C5M).
The demo software is loaded on an Arduino, the Arduino pins and antenna are connected to the RFID module as shown in the wiki documentation and source code.
The power LED on my RFID module lights up as expected, but the signal LED remains dead.
Only when connecting to the 5v power pin from Arduino will the signal LED flash briefly, as the reader starts up.
I have been trying to get a reading using the 125kHz card and key tags (5-combo set) with no luck.
Cannot even trigger a single blink from the signal LED this way (I assume these cards/tags are compatible with this reader).
All connections have been tested/disconnected/connected several times, just to make sure this is not caused by a bad wire somewhere.
Using a multimeter, I measured the antenna DC resistance as well - it does not seem to be broken (resistance is low).
I would appreciate any feedback to help me get this module up and running.