Hello, the GPU I'm trying to repair produces no signal, fans spin at 100% all the time and isn't recognized in Windows at all. All chokes have voltage, resistance from GPU power delivery to GND is at ~1.1 Ohm (1.7 on multimeter) so I guess it's OK. It recognizes no PCIE power plugs with its speaker. The weird thing is that the core hardly heats up - by that I mean that the MOSFETs on power delivery are hotter than core, but at the same time I can't feel any component burning hot. Previous owner told me that it had artifacts, so I feel like it might have been in oven or under hot air gun guessing by weird looking sticker right over PCIE connector. My random guess is that it has corrupted BIOS or dead GPU core. As I don't have an external programmer can I do anything to rule out one or the other?
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8800 GTX no signal
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Re: 8800 GTX no signal
Take meassures of other rails, 5V, 3.3 and so on. (Resistance to ground and voltages). Meassure bios chip voltage, look for its datashhet and look if its 1.8V or more. Start from that. Look for a temperature gun or something to meassure temperatures. The core heats first, then the memmory few seconds later. Look for shorts, test all the fuses you can see and in PCI express connector meassure 12 and 3.3V. Without all that you cant determine what is going on.
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Re: 8800 GTX no signal
So far I've found 2 missing caps - one under the core and one marked as C529, replaced them and I feel like everything heats up more and faster - the core definitely heats up the fastest, then the power delivery, RAMDAC and memory next, but when I try it with heatsink the heatpipes are cold, fan at 100%.
VBIOS is MX25L1005, 2.7V-3.6V, gets 3.29V, but CS# is always high, SO is always pulled to ground and there is no SCLK signal.
The closest I can see to 5V is 4.45V at the MOSFETs gate, core side.
There is only one fuse marked on the PCB, very close to DVI, it's good.
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