Serial Port got burnt?

Posted on 2001-08-17
Last Modified: 2008-03-04
I troubleshooted PDA (Personal Digital Assistant) connection with PC via cable to PC serial port. So I adjusted the serial port setting. Then no matter how, both serial ports refuse to work. Removing the ports then reboot and recreating --- all in vain.
I tested with serial mouse, loopback serial plug and hyper terminal -- all no response.
The ports are solidly grouped with the parrallel port, they shouldn't have wiring fault.

Previously, when failed to get connnected to synchronize, the PDA could still auto switch on, but not now. Only, sometimes later on the hard disk on PC made sounds -- "tick..tick...tick...tick".

BIOS checked.

Parralel port still OK.

Got burnt?
Question by:simala
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LVL 32

Expert Comment

ID: 6396988
>>Got burnt?

Very unlikely.  The serial port is based on RS-232 drivers chips which are very tough.

More likely you don't have your serial ports configured properly in the BIOS setup or have some program running on your PC that is grabbing the serial port.

Please be more specific about "refuse to work".

Author Comment

ID: 6397024
I closed all programs apart from explorer, systray, and the Psion PDA connectivity program itself.
"Refuse to work" simply means even if you try a serial mouse (this mouse was tested on other PC to be OK) on it, it won't work. Both of them.
In Bios setup I had tried to change to other com setting.
LVL 63

Expert Comment

ID: 6397221
I just read that there is the beginnings of a lawsuit agains Palm for known problems with burning out serial ports on certain computers.

This could be  your case !!

I hope this helps !
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LVL 63

Expert Comment

ID: 6397228
LVL 32

Expert Comment

ID: 6397245
Interesting article and I'd agree with:

>>"I wouldn't call it impossible, but at the very least extremely unusual," he added.

Of course when lawyers get involved, nothing can become a big problem.  Even if something is technically impossible there may be legal liability involved.  

In all my years of abusing serial ports I can't ever remember burning one out even once...
LVL 14

Expert Comment

by:Don Thomson
ID: 6397432
If your Serial ports are turned on in your bios and even a mouse won't work then either the bios needs to be flashed or you have blown them up. This can happen via static electricity.  I have serviced serveral PCs that the users complianed that their mouse stopped working. I asked if anything unusual had occured  and they all said that they walked up to their PCs, sat down and heard a loud pop or crack when they touched the mouse. If they are on an ATX motherboard you can either replace the MB (or get it replaced under Warranty if it's fairly new)  or you can add a dual Serial PCI card (lava makes a good one)  and just disable the on-board ones in the bios.

Before you check anything - check in the device manager to make sure there are no conflicts with other devices.

Expert Comment

ID: 6397836
I WOULd say check the bios first and make sure they are both turned on.

also when booting up read the device list which normal pops up and see if they are listed in there.

if all fails for the cost of a comms card id disable if enable in the bios the com port and insert an isa or pci comms card.

windows will automaticaly set this up for you upon boot up./

this maybe the easiest way if you feel they are damaged.


Expert Comment

ID: 6397839
a lawsuit agains Palm for known problems with burning out
serial ports on certain computers.
Funny, I have had to replace about 10 mobos for people running the palms mostly the Vxs.  They said it worked fine until their @home was installed.  I think they were blaming the wrong cause now.  I think they may have been looking for a nedw mobo and already had a failing mobo before we got there.  It is something common I have noticed in pulling work orderd for mobos replaced for that reason.(could no longer access palm after our installation, some several months later)  I am surprised by a couple of things now.  First that a large corporation would replace components in peoples computer systems months after our being there because the customer claims it is our fault without doing any testing.  If the problem was real(occuring during our install), why would the customer wait 3-5 months to call in?  I appreciate the info and will inform the right people in my company.  Anyone need some evidence?

Expert Comment

ID: 6398422
I have replaced 16 motherboards from customers who had the palm. We did our own research and found that the only strange thing was that all the customers were using "import" palms that they had purchased while in the US and brought back to the UK. Could this be the problem?

I would recommend an ISA IO controller card for test purposes. However this will only confirm your findings. if the board is ATX then you may be looking at a new mobo. Also what chipset are you using? All of ours were based on the SIS chipsets.

LVL 31

Accepted Solution

rid earned 100 total points
ID: 6398497
Repeating, but nevertheless: During boot, ensure you have detailed boot messages showing and check if COM ports show up at their normal addresses. Disable them and then reenable. Do a CMOS reset. Connect a known good modem to one and try some old fashioned DOS exercise: Boot to DOS prompt only. At command line type:
copy con COMX  (X being port tested...)
Each line followed by <Enter>
You should see and/or hear *some* reaction from the modem as atz resets modem (if command is coming through).
If no positive reaction at all perhaps your hardware is indeed damaged.

Author Comment

ID: 6399568
Thanks for so many responses. I will try the suggestions and get back to you all.
The PDA is Psion, I am in Australia. The program called PsiWin is used for the synchronization.
LVL 11

Expert Comment

ID: 6399819
May be an issue palmwise with crappy PC standard RS232 implementation which is not to spec. I have seen problems with ports only using +/- 12v  when they should support full RS232 levels, and they don't have the current capacity they should often either.

Author Comment

ID: 6420564
Hi All,
During the booting the serial ports were shown as 3F8, 2F8. Then I removed them from Windows and rebooted to reinstall again. Then I went to DOS. When I plugged to com2, only CS is on on the modem LEDs, when I plugged to com1, TR, CS, TD, RD all on. However, no matter using which port, the only reaction I got is?Write fault error writing device COMx. Abort, Retry, Ignore, Fail?? when press Enter after Ctrl+Z as told by rid.

So I think it is true they got burnt.

I am using Giga-byte mobo, GA-6bxc, the chipset in charge of the ports is ITE 8671.

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