:( got my graphics card back from rma :(

[markiemrboo]

Well this is absolutely typical of my terrificly extreme bad luck.

I sent my dieing (graphics corruption) 6800 back to get it RMA'd, about 2 months(!!!) ago now. It *just* arrived back to me today (9 weeks ish, terrible). I've been waiting so patiently for this card so I can play games again. Serious withdrawl. It's not even funny!

So, it's a brand new spanky shiny card. Very nice. I put the card in, turn computer on. Naturally, because of my apparent "below average" good luck factor, I don't trust many things, so I left the case side off and watched to see if it blew itself up. What happened? A tiny little transistor(???) on the card decided to spark and set fire to itself, followed by an inevitable burning smell.

How's that for a swift hard kick in the family jewels?

*sigh*



I'd probably have a go at hunting down the dead component and replacing it myself, but I am far from an electrician and wouldn't know if anything else had been damaged etc etc. I can use a soldering iron, but that's about as far as I go. I'm all set for another 2 month wait

[Per Hansson]

Re: got my graphics card back from rma

Don't even bother replacing it, it will most certainly just blow up again untill you find the real cause...

[markiemrboo]

Re: got my graphics card back from rma

Don't even bother replacing it, it will most certainly just blow up again untill you find the real cause...

Thought as much

I'll see if I can send this one back for RMA then. Knowing my luck they'll refuse, say they tested it before hand and blame it on a user error or some crap... and I know it wasn't anything to do with me

I am curious though, what exactly is that little component? Is it a transistor?

[tiresias]

Re: got my graphics card back from rma

Thought as much

I'll see if I can send this one back for RMA then. Knowing my luck they'll refuse, say they tested it before hand and blame it on a user error or some crap... and I know it wasn't anything to do with me

I am curious though, what exactly is that little component? Is it a transistor?

It's a transistor, yes. Marked Q518. Q for... erm.. Quansistor.

.

PS. Why are transistors marked "Q"? Just because T (transformer) was taken?

[tiresias]

Re: got my graphics card back from rma

Just took a closer look at the photo you provided, markie.

Q518 and Q519 are two transistors arranged in 'series'. Darlington pair?

[markiemrboo]

Re: got my graphics card back from rma

Just took a closer look at the photo you provided, markie.

Q518 and Q519 are two transistors arranged in 'series'. Darlington pair?

I heard of "Darlington pair" when I was reading stuff for amps the other day, I still dont really know what it actually means though

[PeteS in CA]

Re: got my graphics card back from rma

It's two transistors connected so that the emitter of the input transistor is connected to the base of the second transistor. The two collectors are connected together. The pair can be packaged as a three-terminal device. Why would this be done? The emitter corrent of the I/P transistor is the base current for the second transistor. This means that the net current gain (beta) of the circuit is the product of the betas of the two transistors. For example, if the beta of each transistor is 100, the net beta is 10,000. Stated another way, an I/P current change of 1uA will cause a current change of 10mA in the O/P circuit. One thing that is given up is that the collector-emitter saturation voltage of the device will be about 1V, where a single transistor's sat voltage is about .2V or .3V.