View Full Version : Acer ext modem power supply

15-03-2002, 09:38 AM
I have an Acer external modem, model no.FB M56ESF. no power supply.

Does anybody know how many volts to apply, to see if it works, and how many milliamps it will consume?

Even an experienced guess will do.

Thanks KO

15-03-2002, 10:32 AM
This could be a guide, or it may not be applicable at all:)

Have 2 external US Robotics modems, one has a 12volt AC 1 amp plug pack, the other has a 9 volt AC 1 amp plug pack.
I have also heard of US Robotics being supplied with 15v AC plug packs.

I would be inclined to try a 9v AC plug pack first of all, its almost certain that there will be a bridge rectifier and voltage regulator built into the modem.


15-03-2002, 11:00 AM
Thanks Terry

15-03-2002, 09:26 PM
Well, after what Erins says it really looks as though you may have to take it apart as Graham says to see if its AC or DC, and if it's DC, try to work out the polarity.

Maybe someone with the same model will come up with the answer.

16-03-2002, 07:01 AM
Thanks guys, its definately ac. Has a bridge rectifier, and four diodes.

It won't light up until I apply 15v, then it all works ok.

After about a min, the twin 7508 voltage regulators begin to overheat, then the modem stops being recognized. Could be faulty capacitors, I'll have to dive a bit deeper. Should be quite fixable. Probably should run on 9v.

Cheers KO