Core voltage 2.2 m571 mod question

[Epoch]

Hi all,

I am planning on replacing my PentiumMMX/233MHz CPU with an AMD K6-III (not plus)/450MHz CPU for my M571 motherboard version 3.5 (not 3.5a).

I need to adjust the core voltage to 2.2 volts as many of you have done. I am planning on following the mod shown at http://m571.com/m571/franczabkar/v32corev.htm but looking at my motherboard and at the ASCII schematic, I have a question.

In his diagram the resistors are ABOVE the JP6 jumpers but on the motherboard they are BELOW the jumpers. Do I attach the 39K resistor to the bottom right or top right pin of the 2V8 (R93) jumper pair?

I do not own a digital voltmeter nor would I know how to use one properly if I did. I have an old needle-voltmeter that doesn't even offer correct readings (spring must be worn or bent inside or something) but is there any way to test this before I fry my new CPU? Any clear input would really help.

Thanks!

[Epoch]

I'll answer my own question:


If you test for resistance between two adjacent pins (NOT across the jumper bridge, but side-by-side) you will find that one row (top OR bottom) will have zero resistance between any two pins in that row, while the other row will vary for each pair you connect. You would want to hang that end of the jumper on any one of the pins in the row with zero resistance. They should all connect to the same bus in that row, and therefore not matter which one you connect to. The corner one is probably just more convenient.

The bottom row gave me zero resistance so that's what I will be trying. I will likely post again (if nothing breaks) to confirm that it worked.

[Epoch]

Yeah, at this point I know I'm talking to myself - it's a habit of the old. :rolleyes: I wanted to document it here anyway for those who search the forums with the same question.

Luckily, I read more on m571.com on the m571upgrade.htm page. He mentions there to connect the resistor to the pin farthest from the edge of the motherboard which is what worked (so far no system halts or glitches from poor voltage or overheating).

My old fan was shot though so I grabbed a new one made for socket 7 & 370 chipsets but while the clips are suitable and fit okay, the heatsink itself is a bit too large! I have it pressed against a capacitor or something right now and I'm thinking that's not good. Is it safe to maybe cut off the extra row of prongs on the heatsink?

[alex zorrilla]

I guess it depends on the heatsink, how heavy it is, and how vital the "extra prongs" are. Do you know the model of the heatsink, so I can look it up? Which part of it is interfering with the capacitors?

If you are talking about cutting off extra fins sticking out the side, that is probably OK, as long as you do not bend or warp the rest of the heatsink in the process.

--Alex

[jim chase]

I have it pressed against a capacitor or something right now and I'm thinking that's not good. Is it safe to maybe cut off the extra row of prongs on the heatsink?

Just take a rat tail file and make a notch in the heat sink where it's touching the cap.

Jim

[Epoch]

I'm going to just shave a bit off with a round (rat tail?) file. Cutting off one row of fins would likely be fine and it wouldn't interfere with the fan clips for mounting the fan either but why shave off more than I need to? And yes, I'll be sure to take care not to damage the mounting surface.

Thanks for the replies.