The following website provides info on how to contact a company that will pick up old electronic equipment that you want to get rid of. There is no charge except for computer monitors and televisions.
You can also call them (toll free) on 855-213-5225
"eWaste eXpress provides consumers with a free and convenient way to responsibly recycle your old computers and electronics.
Simply call us to schedule a pickup. Then leave your unwanted computers and electronics at your curb on your scheduled day."
eWaste express will pick up anywhere in center city including high rises.
The City of Phila also takes these at their drop off center on Domino Lane in Manyunk.
The problem, of course, is that so many people in Center City do not have cars. If they do, NTR at 1524 Brandywine St will take computers, monitors. NTR is Nonprofit Technology Resources and they refurbish the equipment and make it available at very low prices. They train people at the "factory" to improve their computer skills.
Directions at: http://ntrweb.org/contact/directions/