The Vcc pins should all be in parallel. It should be sufficient to just check some random subset of them.
I don't know about the jumpers, sorry.

Don´t worry about the 5V voltage. If your PSU is o.k. it delivers exactly 5V at the 5V rail. The mainboard just passes it to the (multiple) pins of the CPU.
If your board has an additional voltage regulator for later CPUs you don´t have to manually select 5V for a 5V CPU by jumpering since the circuit on the mainboard gets a "5V CPU present" signal from the CPU that makes it turn off (bypass) the regulator.

You cannot damage a 5V CPU here by false jumpering, there´s only a problem when you use a Cyrix, AMD or Intel DX4 CPU (that demand lower core- voltages) without jumpering correctly before.

Why not take a picture so we can see the details...

Thanks majestyk I found another manual that says for jumper JP32 (the only one I have for voltage):

Intel DX4/Cyrix DX2-V Voltage Selector: JP32
This jumper selects the CPU voltage for these two CPUs. The Intel CPU uses 3.45 volts and the Cyrix CPU uses 3.6 volts, so you must make sure that these jumpers are set correctly. The default setting is for the Intel CPU, so you do not need to change the setting if you do not install a Cyrix DX2-V.

Clock Speed JP32
Intel DX4 (default) 1&2
Cyrix DX2-V 2&3

In another manual it says JP12 and JP15:

Function: JP12 JP15
3.3V (DX4) pins 2&3 closed pins 2&3 closed
5V pins 1&2 closed pins 1&2 closed

On my rev 2.0 board JP12 and JP15 are missing you can see where they were next to the second voltage regulator on the right in the picture below

I would still like to see if the socket 3 is supplying 5 volts even with JP32 set to 1&2 and IIRC there is a bios update to enable a DX266 overdrive I cant remember where I saw this maybe from Phills Computer Lab, youre right this board has 2 voltage regulators so when you said that a 5 volt CPU tells the motherboard/socket to supply 5 volts straight from the power rails can you tell me which pins on the socket 3 are for this so that I can jumper them and test if its supplying 5 volts.

In this Socket 3 generation what you see at the bottom-right corner does not mean "2 voltage regulators" but 1 voltage regulator (the left one with cooling) plus 1 MOS-FET (the right one) as a simple switch to bypass the voltage regulator in case a 5V CPU is present.
That´s why JP12 and JP15 have become obsolete for this mainboard revision.

Ok thanks for clearing up about the second one as a mos fet which means to me there are pins that still get used to detect if a 5 volt CPU is used or not do you know which pins they are?

Hi GabrielKnight123,

As explained by majestyk, this nice 486SV2GX4 board has Vcore autoswitching to support all 486 CPU models. With JP32 set at 1&2, it automatically switches between 5V and 3.45V, depending on the installed CPU.

If you are set on testing this, you can use the procedure from my Am5x86 upgrade story at http://www.steunebrink.info/amd5x86.htm
Look under the header “CPU Voltage” and omit step 3 (wire between pins S-4 and R-4) if you want to test for 5V Vcore.

The latest BIOS for your Rev 2.0 board is Rev. #401A0-0402-1. This 11/03/95 BIOS supports all 486 CPU models, including the Cx586 and Am5x86-133. But software wise, your DX2OPDR66 is just an 80486DX2 and will be supported by all BIOS revisions for this board.

Happy New Year,
Jan

Edit: updated the link to my website

It´s the "S4" = VOLDET pin.
It drives the gate of the switching MOSFET.

Thank you majestyk and Chkcpu I'll test it when I can I mainly want to check everything because this motherboard will have my MPU-IPC-T Midi card and Pro Audio Spectrum 16 and maybe a Am5x86

Thanks Happy New Year to everyone too