mesure Vcore

[ianomami]

How can I measure Vcore on AMD K6-2 500 and P200MMX?
I have an old board M537DMA. It hasn't got any votage monitor.
I have an ordinary meter that measures votage, amper, resistance etc...[I don't know how is it called in English]. Can I use that?

[This message has been edited by ianomami (edited 10-05-2000).]

[drn]

i dont think there is a way to do it if the mobo does not support it

[embalmerd]

You could try Motherboard Monitor:
http://members.brabant.chello.nl/~a.vankaam/mbm/

[ianomami]

Thanks a lot for the replies but I guess I did not express myself clearly. I wanted to ask a lot using too few words. So I will tell the whole story:
I have a P200MMX running on a PcChips M537DMA at 3.5x75=266MHz and I want to upgrade to a K6-2 500 or so.
My old board doesn't support CPU core voltages lower than 2.5 for AMD's latest socket 7 CPUs that operates at 2.2V and I've found this nice webpage explaining how to get a safe 2.3Vcore only disordering a resistor! And the he explains the procedure on how to check the voltage:
"By wrapping a single strand of a multistranded wire around the Vcore pin on the CPU at location B2 (on the AMD documentation) and leaving it outside the ZIF socket I was able to clamp it to the +ve lead of my DVM, -ve lead was clamped to chassis ground so I could monitor the results of 'dialling in' different resistances."
The problem is: my english sux. I'm not sure what exactly a DVM is. My Webster definition for DVM is "Doctor of Veterinarian Medicine" Well, I have that little eletronic device that measures votage, ampere, resistance, etc. Is that a DVM?
<IMG SRC="http://c.postmypic.com/c.nsf/z/DVMPRUD/$file/DVM.gif" border=0>
I'm asking because I've read the Intel Pentium document about VCC2 and VCC3 Measurement Specification and it says: "The values of VCC2 and VCC3 should be measured at the bottom side of the processor pins using an oscilloscope with a 3 dB bandwidth of at least 20 MHz (100 MS/s digital sampling rate). There should be a short isolation ground lead attached to a processor pin on the bottom side of the board." It sounds very complicated and I don't have an oscilloscope anyway...
And what does "chassis ground" mean? Could it be any grounded piece of metal? What can I use as a "chassis ground"?
And finally... can I proceed the same way to measure the voltage of my P200MMX? If so, which CPU pin should I use for measurement?



[This message has been edited by ianomami (edited 10-05-2000).]

[skeegin]

ianomami
What web page is that?
After you remove the resistor to get a lower voltage, are you sure your motherboard's cpu voltage regulator can put out enough current for the K6-2? You may have to put a heatsink on the regulator.
DVM stands for 'digital voltage meter'
For chassis ground you could use the metal surrounding the keyboard socket.
Isn't a P200MMX a socket 7 cpu? Wouldn't they use the same pins for input voltage?

[This message has been edited by skeegin (edited 10-05-2000).]

[ianomami]

Thanks. this is the page: http://www.zarniwoop.force9.co.uk/index.htm
I've tried to contact him but I think he is on vacation.

"After you remove the resistor to get a lower voltage, are you sure your motherboard's cpu voltage regulator can put out enough current for the K6-2?"
Good question. I don't know much about eletronics.

"Isn't a P200MMX a socket 7 cpu? Wouldn't they use the same pins for input voltage?"
I have both AMD K6-2 and Pentium MMX's pin description diagram and the B2 pin is Vcc2 for AMD and INC [Internal No Connected] for Pentium. There are many Vcc2 and Vcc3 pins. I guess I can use any of them...

[skeegin]

Oh yeah, I remember that web page.
You have the same motherboard as he does right?... so it should work?
Sorry I am not familiar with what the input/output voltage pins are named in technical documents.
It seems likely that all inputs named Vcc2 would be the same.
I hope it works for you.