i have a cable modem that i lost the power cord to. i found another that fits but the output listed on the adapter is 12.5vdc. the modem lists +12vdc. can I use them together? i plugged it in and it lit up for a while but then went out but I don't really know how the modem is supposed to work if there's no internet connected to it.
first! are you sure the modem needs 12 V DC and not 12 V AC? Mine uses AC. OK, you can use a 12.5V in a 12V modem - the extra .5V is not a problem... Next, make sure the polarity is correct!! center pin is the correct polarity? If not, POOF! You will let the smoke out. Have you considered that the modem is bad and the power supply is not the problem here. If the modem is bad, you may have killed the supply you plugged in.
You need the correct voltage and the correct current (amps) from your adapter. Look at the old adapter - it will say what the current output is (e.g., 2 AMPS).
