Having too much amperage available wouldn't be a problem. Voltage is most definitely an issue.
the 4000 through 7000 modems use 19.5V and 6.5V. I finally found an image online for the 9000 PS that was large enough for me to read the voltages, which were 48V and 13.5V.
Not sure why someone here couldn't tell me that if they had a PS to look at.
Author of hnFAP-Alert, PC-OPI and DSSatTool