jerry@sfsup.UUCP (Jerry Theisen) (02/03/88)
I have an AT&T PC 6300 that has worked without a problem for 2 and a half years. Now for some reason, the serial port has up and died. These are the symptoms: I hook up a modem (AT&T 4000) and an rs232 cable. I enter my communication program (ctrm). As I enter characters the transmit light on the modem blinks, but nothing is echoed on the screen, and indeed the receive light on the modem (those that have one) never blinks. And I cannot get the usual modem prompts. I hooked up the cable and modem to another 6300 and both work fine (same settings of 1200 baud, 8 data bits, 1 stop bit, no parity, and com1 as the port). I ran the customer diagnostics program and it says the serial port is installed and working fine. But if the serial port is fine, and the modem is fine, and the cable is fine, then what could the problem be? Since the modem and cable work on other machines, I have to believe it's the port. I tried installing another serial port, but can't get the 6300 to recognize it. Is there a dip switch somewhere that I set to tell the 6300 that there are 2 serial ports installed? If not, should it automatically recognize the additional port? Is there a way to simply disable the primary port? Thank you in advance for any help you can give me. Jerry Theisen attunix!jerry
prn@whuts.UUCP (NEWELL) (02/04/88)
In article <2742@sfsup.UUCP>, jerry@sfsup.UUCP (Jerry Theisen) writes: > I have an AT&T PC 6300 that has worked without a problem for 2 and a half > years. Now for some reason, the serial port has up and died. > These are the symptoms: > I had the same problem on a 6300 once. The cause was a failure in the -12V output of the power supply. I opened the supply to find a cold solder joint on the -12v regulator. It cold also be a failed line driver chip. These chips are not tested by the standard diagnostics. Good luck. Paul Newell whuts!prn
aptr@ur-tut.UUCP (The Wumpus) (02/05/88)
In article <2742@sfsup.UUCP> jerry@sfsup.UUCP (Jerry Theisen) writes: >I have an AT&T PC 6300 that has worked without a problem for 2 and a half >years. Now for some reason, the serial port has up and died. >These are the symptoms: > > I hook up a modem (AT&T 4000) and an rs232 cable. > I enter my communication program (ctrm). > As I enter characters the transmit light on the modem blinks, but > nothing is echoed on the screen, and indeed the > receive light on the modem (those that have one) never > blinks. And I cannot get the usual modem prompts. > >I tried installing another serial port, but can't get the 6300 to recognize >it. Is there a dip switch somewhere that I set to tell the 6300 that >there are 2 serial ports installed? If not, should it automatically >recognize the additional port? Is there a way to simply disable the >primary port? The first question is "Did the problems start to occur just after adding a board to your computer?" If so, the problem is not the serial port, but the interrupt structure of the hardware you are using. There are a fixed number of interrupt lines that can be used by hardware. Some of these lines are already used by the 6300's onboard parrellel and serial ports. Since you say you tried to install another serial port, was it before or after the problems started. If it was before, the problem is in how the serial board is configured. Check your documentation on the serial board and make sure the board is set up to be COM2:. The change would be done on the board and will probably involve moving jumpers. If you installed the serial board after the problems started and installed another board before the problems started, check to make sure that the other board is not trying to use the same interrupts as COM1: (the 6300 serial port). The information on the interrupts that the board is using should be in the manual. A simple way to check if the interrupt problems were caused by a new board is to remove the board ans see if the built in serial port works. There is no switch on a 6300 to tell it the number of serial ports you are using. The hardware and software will recognize the number of ports if they are configured each as a seperate port (ie. 1 serial port is COM1:, the next is COM2:). I know of no way to disable the onboard serial port. -- The Wumpus UUCP: {cmcl2!decvax}!rochester!ur-tut!aptr BITNET: aptrccss@uorvm Internet: aptr@tut.cc.rochester.edu Disclaimer: "Who? When? Me? It was the Booze!" - M. Binkley