I've been reading the I-Opener board for the last 5 weeks and decided to take the plunge and upgrade the CPU.
I carried out Tackheads mod as described in this thread:
K6-III mod w/adjustable Vcore for V1
But wherever the 50K pot is set to I always get 2.5V on the VCore of R60/61 I've checked in the BIOS and it also says 2.5V I'm ideally looking for a variable Vcore voltage of between 1.6 and 2.9 but can't for the life of me figure it out.
I've checked and double checked my work and everything is fine as regards to soldering.
This is the picture of the resistor mod near the max chip:
(The other wires are just for multiplier adjustment)
I enabled Split-plane voltage by moving R60/61 to R184/185 and checked continuity.
I've removed R202 and now it's bare OC
I lifted pin 3 of U16 and soldered a link from the pin on the IC to one side of the 50K pot.
I soldered a 100K resistor on the 2.5V side of R276 then linked to the other side of the 50K pot. Then from the same pin on the 50K pot I linked to the other side of R267 (GND)
As far as I know this should be correct.
Across the resistor I got 100K
Across the pot I'm getting between 0 and 49K adjustable
From the pin of U16 to the output of the pot I'm getting 0 ohms
From the pin of U16 to the 100K resistor I'm getting between 0 and 49K adjustable by the pot
From the pin of U16 to after the 100K resistor where it's soldered to R276 I'm getting 92K to 143K
If you could help me I'd be exremely grateful, this has been driving me crazy for a while now.
Thanks for any help, if I can give you any more info just ask.