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Last reply by 11-20-2006 Unsolved
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2 Bronze
2 Bronze
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Dell 2400 serial port dead?

Hi, everyone...

I have a Dell 2400 that is used to display my home weather station, and it also feeds the station data to Weather Underground. The weather display/feed software gets it's data from the weather station via a serial interface.

A few days ago, after rebooting the system after downloading some critical MS updates, the weather software displayed a message that it "Could not open comm port". I checked to make sure the software was set for the correct com port (com 1) and it was. I went into device manager and checked that something didn't happen to the com port, and it showed com 1 was still there. I plugged some other serial devices into the com port and rebooted each time, and nada.

I contacted Dell tech support on-line, and over the course of an hour or so, the tech had me check a myriad of things, and conduct some tests. We made sure the com port was still active in the bios (it was) . We forced it to be com 1 (instead of "auto" ). We rebooted into the diagnostic partition, and checked the com port, and it said it was good. We then tried to test it via Hyperterminal, and thats where things went south. Hyperterminal said the port was in use. It wasn't...nothing was plugged into it, and the modem is on com 3. The tech decided I needed a new motherboard (the one time an extended warranty has actually paid off), and two days later, a technician was at the house with new MB. He changed out the new MB, and when we rebooted the computer, the same error message came up. Obviously it doesn't appear that the original serial port/MB was bad, because we shouldn't have the same message problem again. I told the technician that the problem arose after doing a MS Update, and he suggested that there may have been a problem with one of the updates. He suggested going into system recovery and restoring to a previous time. We went back about 2 weeks. The system did it's thing, and after that, still end up with the same problem. Now I'm stumped.

I think that this problem is actually in the OS. I think that I need to go into device manager, and deleted the serial port, reboot the computer and let WinXP find it again. I'm not sure that'll work, but I can't think f anything else. Anyone have any suggestions?
All help greatly appreciated.

Message Edited by Bob F. on 11-18-200606:34 PM

Message Edited by Bob F. on 11-18-200606:34 PM

Replies (9)
4 Ruthenium
275

Could be you have the wrong irq for that port. Drawing on my memory which is hard to do sometimes com 1 irq should be irq 2 & 4 and com 2 should be irq 1 & 3. Check to see what irq is for com1 and also try to add com 2 if not showing from control panel add/remove hardware. Look in bios setup and see what these 2 pots are set at. But the MB uses com1 and you should avoid putting things like modems or anything on the port with irq 2 and 4.
Look in control panel>device manager and under ports see in the properties if com1 under resources shows it at IRQ 04 and I/Q range at 03F8-03FF
2 Bronze
2 Bronze
275



@dbramlet wrote:
Could be you have the wrong irq for that port. Drawing on my memory which is hard to do sometimes com 1 irq should be irq 2 & 4 and com 2 should be irq 1 & 3. Check to see what irq is for com1 and also try to add com 2 if not showing from control panel add/remove hardware. Look in bios setup and see what these 2 pots are set at. But the MB uses com1 and you should avoid putting things like modems or anything on the port with irq 2 and 4.
Look in control panel>device manager and under ports see in the properties if com1 under resources shows it at IRQ 04 and I/Q range at 03F8-03FF





Thanks for the suggestions. I just checked the port in control panel, and it shows that it is set for the correct IRQ and I/Q range.
8 Xenon
275



Bob F. wrote:
Hi, everyone...

I have a Dell 2400 that is used to display my home weather station, and it also feeds the station data to Weather Underground. The weather display/feed software gets it's data from the weather station via a serial interface.

A few days ago, after rebooting the system after downloading some critical MS updates, the weather software displayed a message that it "Could not open comm port". I checked to make sure the software was set for the correct com port (com 1) and it was. I went into device manager and checked that something didn't happen to the com port, and it showed com 1 was still there. I plugged some other serial devices into the com port and rebooted each time, and nada.

I contacted Dell tech support on-line, and over the course of an hour or so, the tech had me check a myriad of things, and conduct some tests. We made sure the com port was still active in the bios (it was) . We forced it to be com 1 (instead of "auto" ). We rebooted into the diagnostic partition, and checked the com port, and it said it was good. We then tried to test it via Hyperterminal, and thats where things went south. Hyperterminal said the port was in use. It wasn't...nothing was plugged into it, and the modem is on com 3. The tech decided I needed a new motherboard (the one time an extended warranty has actually paid off), and two days later, a technician was at the house with new MB. He changed out the new MB, and when we rebooted the computer, the same error message came up. Obviously it doesn't appear that the original serial port/MB was bad, because we shouldn't have the same message problem again. I told the technician that the problem arose after doing a MS Update, and he suggested that there may have been a problem with one of the updates. He suggested going into system recovery and restoring to a previous time. We went back about 2 weeks. The system did it's thing, and after that, still end up with the same problem. Now I'm stumped.

I think that this problem is actually in the OS. I think that I need to go into device manager, and deleted the serial port, reboot the computer and let WinXP find it again. I'm not sure that'll work, but I can't think f anything else. Anyone have any suggestions?
All help greatly appreciated.
 
I would agree that deleting the port and rebooting is a good next step.

With over 30,000 posts (through early 2007), Rickmktg hasn't bought a Dell computer since July 2005, but has bought two Lenovo laptops...   

http://www.rickmktg.com/delltalk.htm

4 Ruthenium
275

Ok, have you look in bios setup also? You have one or 2 serial ports on that board? Maybe you can open it up and see if the ports are intergrated on the board or are there cables connecting it to the board? Just checking for the most obvios things. If you change the MB and it has cables make sure they are installed correctly. But you should be able to find something somewhere.
2 Bronze
2 Bronze
275



@dbramlet wrote:
Ok, have you look in bios setup also? You have one or 2 serial ports on that board? Maybe you can open it up and see if the ports are intergrated on the board or are there cables connecting it to the board? Just checking for the most obvios things. If you change the MB and it has cables make sure they are installed correctly. But you should be able to find something somewhere.





There is only 1 com port. The ports are integrated to the board, so no cables. When the tech changed out the MB, we did make sure that the port was enabled in the bios.
4 Ruthenium
275

Ok, better stay with rickmktg suggestions and help then.
2 Bronze
2 Bronze
275

Thanks, guys. It seems thats the only option left. I appreciate the help!
2 Bronze
2 Bronze
275

Just wanted to follow-up. I deleted the serial port in device manager, rebooted the system, and the serial port was reinstalled, and now works. Go figure. I would've thought that tech support would've thought of something so simple...
8 Xenon
275



Bob F. wrote:
Just wanted to follow-up. I deleted the serial port in device manager, rebooted the system, and the serial port was reinstalled, and now works. Go figure. I would've thought that tech support would've thought of something so simple...
Yup.

With over 30,000 posts (through early 2007), Rickmktg hasn't bought a Dell computer since July 2005, but has bought two Lenovo laptops...   

http://www.rickmktg.com/delltalk.htm

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