PowerBook 180 serial ports not working

[jcs]

I can't seem to get any traffic flowing between the modem or printer ports on my PB180, talking to an Apple Modem 300/1200 or any other RS422 device (or RS232 devices through an RS232->RS422 converter that works on my Mac Plus) through an Apple DIN8->DB9 connector.

It does have an internal modem which works, and in the PowerBook Setup Control Panel window, I can toggle between internal modem and external modem with no success. When the internal modem is removed, that option in the Control Panel window is no longer available.

I'm guessing it's a hardware issue with the motherboard, but aren't both serial ports and the modem all connected to the same chip, along with SCSI? The internal SCSI2SD hard drive works fine.

Any ideas?

 

[demik]

My guess is that the SCC part of the 85c80 combo chip is bad given that none of the ports are working. So yes it's the same chip, but one part can be bad and the other can be fine.

The modem, however is not always connected to the SCC. Starting with the PowerBook 160/180, modems could use either the SCC or a different bus (SPI). I'm guessing your modem is a SPI one

No idea except to try a motherboard swap tho.