Dell fried

Alan Case · May 24, 2005

Well the end of another **** day.
Plugged my notebook in to a Trio datacomm radio via the serial port, 10 seconds later the notebook dies with a horrible burning smell. Has anyone else ever fried a ??? from the serial port and what was involved in the repair. Dell Inspiron 8500
Regards Alan Case

panic mode · May 24, 2005

i can't think of any way of frying laptop through com port.
was this the ONLY cable that was connected to laptop?
how about laptops power supply? i could see someone frying
laptop if PSU goes bad (not isolated anymore) and someone
screwed with panel wiring (programming port or plc/radio modem).

Mark Buskell · May 24, 2005

Fried Port

I haven't fried the serial but my company has fried the PCMCIA ports on a Dell 8600 4 times. We believe that the voltage is underrated. Dell has since upgraded our service agreement to 3 years because of this problem. Our solution is to let the laptop boot up first before connecting any aux interfaces (PLC5 or SLC504 using DH+).
As far as repair, if it is under warrantly, Dell has that next day onsite repair. If you need to send it back and you do not have the box, you can request that the UPS / DHL man bring a box when contacting Dell.
Dell is generally good with repairs, make sure contact the business repair and not home repair, otherwise you will be speaking to some Indian named Jim or Tina that will have you jump through hoops before finally refering you back to the states.

rsdoran · May 24, 2005

Its possible if wrong cable was used and you connected to a power source.

icky812 · May 24, 2005

The usual cause of this (at least the few times I have seen it) is that the ground is floating on the RS-232 port on the device that you connected to. In this case the Datacomm modem.

The voltage that is present shorts the port out and presto you have a paperweight.

If it makes you feel better I did this myself once to a desktop. Not quite as bad since it only smoked the port, but I went ahead and changed the motherboard anyway.
Now before plugging into a device I usually check for ground voltage just for kicks.

Alan Case · May 24, 2005

I triple checked the serial cable connections. The notebook was running for an hour or so before connecting to the radio unit which was brand new.
The radio port B (the port I connected to) has a voltage of 0 - 5 V on pin 9 that is scaled to the transmit power, but the lead I was using has no connection to pin 9. Seems to much of a coincidence but at least the hard drive and work is salvageable. Alan

gbradley · May 24, 2005

I fried the serial port on my AMS roadster a few years back.
I was hooking up to SLC /03.
Anyhow, I didn't know what I was doing (Like I do now

yeah right

)
That's how I found about PCMCIA to serial converters

RRobbins · May 25, 2005

I fried the serial port on a Dell 840c laptop. I had the extended "in home" warranty. They sent a new motherboard to a local repair guy. He came out and replaced it in an hour. The mother board was overnighted to him. I have all Dell computers, now. I was impressed. The origial problem was a NEW operator panel had shorted the 24vdc to the 5vdc pin.

S7Guy · May 25, 2005

I had the same experience as RRobbins, except I caused the problem myself. It was a Dell 8500, and I was reaching around trying to plug in the power, when the round power plug grazed the com port pins. It blew the motherboard instantly. In my defense, I found it an idiotic design that the power plug is right next to the com port and has a shape that allows it to contact a pin. My earlier Dells weren't like that.

Anyway, I always buy the priority warranty from Dell, and a tech was onsite the next morning with a new motherboard. From my experince, Dell service has been awesome.

panic mode · May 25, 2005

it's time to invest in optically isolated RS232 port...(preferably USB<>RS232)

Steve Crotty · May 25, 2005

It was my understanding that most RS232 ports nowadays are optically isolated? Maybe on the the odd motherboard they decide to try and save a penny or two and not include that.

jimbo3123 · May 25, 2005

Mark Buskell said:
I haven't fried the serial but my company has fried the PCMCIA ports on a Dell 8600 4 times. We believe that the voltage is underrated. Dell has since upgraded our service agreement to 3 years because of this problem. Our solution is to let the laptop boot up first before connecting any aux interfaces (PLC5 or SLC504 using DH+).
As far as repair, if it is under warrantly, Dell has that next day onsite repair. If you need to send it back and you do not have the box, you can request that the UPS / DHL man bring a box when contacting Dell.
Dell is generally good with repairs, make sure contact the business repair and not home repair, otherwise you will be speaking to some Indian named Jim or Tina that will have you jump through hoops before finally refering you back to the states.

I've had this exact same thing happen to me on an 8600. I've seen it on a couple of other 8500s too. Never had any problems with the serial port though.

Steve Meisel · May 25, 2005

I have had my Dell 8600 in for repairs two times in the last year. First time the volume buttons stopped working, had to replace the motherboard. The second time the PCMCIA slot wouldn't recognize when a card was inserted. Replaced the motherboard then too. We had another 8600 that the PCMCIA slot stopped working in it too. New motherboard in it too.
Dell's service has been outstanding on the getting the repairs done quickly.

RussB · May 25, 2005

A few (6-8 or more, time goes too fast) years ago one of our local machine builders went to start up a PLC that was powered from a control transformer in the cabinet. He plugged his computer into the outlet on the wall near the machine. These two power sources must have been out of phase and/or had very large ground differentials. When the serial cable was plugged into his compter a "lunchbox" (remember those?), the RS-232 to RS485 converter that was plugged into the PLC literally blew up. It took out the serial ports on both the PLC and PC along with it. It could have been much worse, as no one was hurt. Scared the wind out of everyone in the area too.
The really bad part is that I was supposed to have been there to make sure that everyting went smooth on this start up.

Doug_Adam · May 26, 2005

I've never fried a PC, but I have got a tingle from a serial port due to a floating power supply. In this case, with no earthed DC, the voltage could float to 240V and thus give that nice tinglly fealing when touched.

Dell fried

Alan Case

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panic mode

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Mark Buskell

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rsdoran

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icky812

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Alan Case

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gbradley

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RRobbins

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panic mode

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