Are some of the capacitors on ATI 9800 Pros glued on? I just got one in the mail from an eBay seller and one of them was off. It is about ¼ inch diameter and ¼ inch high... perhaps closer to 3/16th on both height and diameter, silver with a black part to it. It has the numbers 100/15S/3P3 on it in a vertical order. The bottom is black plastic with two wires sticking out to the left and the right. There seem to be four such capacitors like this one on the board…. The three others are all in a row. It sure looks like it was glued on. It was an as/is untested deal, so I will get nowhere with the seller… from the UK. I would rather attempt to fix the thing. It was poorly wrapped and the heatsink/fan was missing one screw; it was completely off, and the fan sure could have knocked this thing off.
Thanks... I found a picture online that has the layout of this card... it is not quite the standard ATI or Sapphire layout, but it has the stock ATI looking fan on it. On this card, the place where the capacitor came off is a 1/2 inch below where the fan usually plugs in. If the image below makes it up, the wire to the fan is over the top of the capasitor.
It is an R350 core... but if it does not work, I will not have to worry about that...
"Surface mount chip capacitors on an Asus video card. See their black surface mount seats which are at the bottom of each cap. The black mark on the silver top of the cap indicates the negative lead. The seat is also square at the negative side. It is not clearly apparent from the markings, who manufactured these caps. Why would they use these surface mount chip capacitors instead of normal radial lead capacitors? Well it is easier to place and solder them to the board with machines."
You could have used the card without the capacitor. Capacitors don't complete circuits; no current actually goes through them from point A to point B. They just act like little batteries in the event that a ripple needs to be smoothed in the signal. The better the input current, the less the need for capcitors. That's why you see few capacitors on eight phase motherboards compared to four phase boards.
I've knocked off four rice grain sized surface mount caps on a single motherboard and it never affected the mobo in the slightest. If you have a lousy PSU you could even replace the caps with ones of higher capacitance if the opportunity presented itself.
Good job on finding a place that can fix surface mount solders. Most places don't have the skill.
I brought the card into a local electronics shop today and the guy there charged me $2.25 + tax to solder it back on. He seemed to do a fine job, and the card was up and running.
I still cannot believe the poor packing job the guy who sold it did.
They just act like little batteries in the event that a ripple needs to be smoothed in the signal. The better the input current, the less the need for capcitors
Theese small capacitors on very high speed circuits don't act as ripple leveller, they are here for theese 2 purpouses:
1. they provide very high current (in the order of 100-200A) for very short sudden peaks (in the order on tenths of nanosecond): no PSU in the world can react so fast, if it would do this, it would be unstable and start self-oscillating at the moment of load reduction.
2. they filter the high frequency switching noise generated by RAM, GPU and DAC in order to limit EMI and not disturb other circuits connected to the same rail
If you have a lousy PSU you could even replace the caps with ones of higher capacitance if the opportunity presented itself.
Nothing more wrong than this!
You never must replace capacitors with others of different value or dielectric material in a high current DC-DC converter, because ir's calculated for the exact load capacitance and ESR inserted. If you raise or lower the load capacitance or ESR or transient response it can become unstable and burn out in a matter of seconds also damaging your CPU.
If you have a poor PSU replace it, not the capacitors.