*mad scientist laughter*
The chipped VT242WF is dead. That's a given, as it's missing a piece. I confirmed this by once again plugging in the card and probing the poor thing with a DMM. The other memory voltage read around 1.52v which is ok for GDDR5, but the other was 0.036v. Now that's a problem, and there's little to be done about it. I certainly can't fix or replace the broken VT242WF as it's a BGA part with solder balls under it. I can't practically rebuild the phase. But the thing is, there are
two VT242WFs on a reference HD4890. One produces memory vDD and the other vDDQ. And since these voltages are very close to each... See where this is heading?
I figured I have nothing to lose, right? The card doesn't even boot as it is. I decided to perform a surgical... erm... a soldered "vDD/vDDQ bypass".
Here's what I did:
I desoldered and lifted the anterior leg of the inductor of the broken memory phase, effectively cutting off the broken VT242WF from it's inductor and as such, it's load. Then I simply bridged the two inductors by their anterior legs, meaning both memory vDD and vDDQ are now fed by the same converter. The broken VT242WF has no load anymore. Like it didn't exist anymore.
Installed the HSF.
Plugged it in.
Plugged both 6pin plugs and DVI.
System power on.
Monitor status led was yellow, meaning no signal. But that's normal It will take about 5 seconds for the VGA to give a picture.
Seconds feel unusually long...
Dissapointment creeps below my skin.
But what's this?
Monitor status: BLUE LED!
There's a bloody video signal!
Quarter of a second later: POST screen! Sweet, sweet POST screen!
I have no idea how this hackjob will affect the card in practice. I reckon memory won't OC much after this. It's also quite possible that it wouldn't even be 3D stable... Dunno yet, because just that things wouldn't be
too easy the OS on my Vertex SSD got corrupt earlier today by some weird twist of fate for reasons which are beyond me.
So, it'll be some time to run some 3D on the card...
