I would say there's likely to be three multiplier switches, like on a motherboard, but overriding the motherboard ones, that go to the pins on the top CPU socket, and they are likely to have 10Kilohm resistors on them. Then there's likely to be 5 for setting voltage on that chip you see, which probably have a variety of different resistance values and work like voltage settings on a lot of motherboards. So if original docs are not to be had, you can bleep out the multi pins from a CPU pinout and figure out the voltage settings from the datasheet of the chip and the resistance values.

I found a datasheet for the RC5036: https://www.datasheets360.com/pdf/635297678915034898

Page 9 has an example/refernce circuit, which Kingston may have followed and could be useful to work out what the switches connect to.

Many thanks for the tips and datasheet, I'll look into it a bit more!

I’m trying to figure out jumper settings on mine, did you have any luck?

I can find manuals for it but no dip settings listed..

Unfortunately not, the motherboard I wanted to use for the K6-2 did not support the processor properly so I gave up on the subject.

I think as Bitwrangler suggested, that if the manuals don't include DIP switch settings (they're factory set and sold with CPU fitted, so probably not), then it's going to mean working out what's connected to what. Better photos would help, showing the resistor values. Some traces will show what the connections are, and knowing resistor values might mean it's possible to make a guess about which the voltage output resistors are, based on the Vout=1.5*(1+R1/R2) given in the RC5036 datasheet (same formula for both outputs). But there will be enough traces going under components that any guess will need to be confirmed by checking.

Garrett W wrote on 2021-12-20, 10:39:

Unfortunately not, the motherboard I wanted to use for the K6-2 did not support the processor properly so I gave up on the subject.

Ask user chkcpu to mod your bios if it isn’t listed on his website (jan)

http://web.inter.nl.net/hcc/J.Steunebrink/k6plus.htm

snufkin wrote on 2021-12-20, 12:19:

I think as Bitwrangler suggested, that if the manuals don't include DIP switch settings (they're factory set and sold with CPU fitted, so probably not), then it's going to mean working out what's connected to what. Better photos would help, showing the resistor values. Some traces will show what the connections are, and knowing resistor values might mean it's possible to make a guess about which the voltage output resistors are, based on the Vout=1.5*(1+R1/R2) given in the RC5036 datasheet (same formula for both outputs). But there will be enough traces going under components that any guess will need to be confirmed by checking.

On mine I’m pretty sure that the first three left to right are probably the bf0, bf1, bf2 registers for setting multiplier

And the rest to the right I’m pretty sure are the voltage settings

Assuming that it works like any old socket 7 motherbord all off should give the lowest voltage and probably from left to right should be +.1v, +.2v, + .3v+, .4v, +.8v or something like that

I’ll have to do some experiments

The 3 clkmul pin positions on the cpu/socket are in known positions

You could on a bench use an ohm meter testing each clkmul pin by flipping every dip switch one at a time to see which dip attaches to which clkmul

If I had to guess the 3 dipp switches that are up relate to the 5.5x multiplier and unless you want to use 6x there is likely little reason to change them

The other dips likely affect other things like voltage and it’s doubtful they go below 2.2v

rmay635703 wrote on 2021-12-20, 19:42:

The 3 clkmul pin positions on the cpu/socket are in known positions […]
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The 3 clkmul pin positions on the cpu/socket are in known positions

You could on a bench use an ohm meter testing each clkmul pin by flipping every dip switch one at a time to see which dip attaches to which clkmul

If I had to guess the 3 dipp switches that are up relate to the 5.5x multiplier and unless you want to use 6x there is likely little reason to change them

The other dips likely affect other things like voltage and it’s doubtful they go below 2.2v

I am suspecting that my adapter in it’s curent state is likely in the 5.5x 2.2v or 2.4v configuration but I am unsure.

Do you know what pin configuration is required for 2/(6x)?

I can totally figure that out with a volt meter if I have some references to go off of

Edit: confirmed it’s set to 2.2v

Okay 4-8 are voltage switches as suspected

All voltage switches off is 2.020v so this is the base
4 is +0.1
5 is +0.2
6 is +0.4
7 is +0.8

So 2.8v is all voltage switches off except 7

But it gets weird, there appears to be a second tier of voltage settings if you enable switch 8

The second tier has a base of 1.330v

With this new base setting the switch values are cut in half. The +.1v is now a +.05v and so on.

So it seems this adapter can set about whatever voltage you might want!! Awesome!

Ps, not that this would ever happen but be sure power is fully removed when setting these switches, I noted a glitch wherein if full power down wasn’t observed between settings that the regulator would let 5v through instead of the set value.

I can’t imagine a scenario where someone would plug a cpu into a running computer though. But heads up 🤣

Can someone ⭕️ the pins I need to check for those final three switches? Not clear on which ones they are

That voltage pattern rings a bell, and it appeared on some motherboards: Super socket 7 motherboard voltage jumpers.

BF pins are here:

Settings are here:

Okay, I can see 2.020v on all the vcc2 pins and these two images appear to be in the same orientation

Sphere478 wrote on 2021-12-20, 20:16:

Okay, I can see 2.020v on all the vcc2 pins and these two images appear to be in the same orientation

I showed the bottom view of the CPU, forgetting you'd actually want the socket. I think this is right:

Switch 3 is bf
Switch 2 is bf1
Switch 1 is nc (in line with other two pins)

Basically they flip orientation when looking head on a the three switches and pins.

I assume bf is bf0, bf1 is bf1 and nc is bf2

So what settings are required for 2x?

Sphere478 wrote on 2021-12-20, 20:30:

Switch 3 is bf Switch 2 is bf1 Switch 1 is nc (in line with other two pins) […]
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Switch 3 is bf
Switch 2 is bf1
Switch 1 is nc (in line with other two pins)

Basically they flip orientation when looking head on a the three switches and pins.

I assume bf is bf0, bf1 is bf1 and nc is bf2

So what settings are required for 2x?

NC? It looks like switch 1-3 go to R6,7&8 (330 ohm). Seems unlikely they would fit all three resistors for one to be NC. Datasheet (I edited post just above yours earlier) says 2x/6x is BF[2..0] = 110b.

[edit: just looked up the datasheet for the 5057 and it gives the 5 bit voltage table there, seems to match what you found, 1.30V to 2.05V in 0.05V steps, then 2V to 3.5V in 0.1V steps. It's actually quite a different design from Garret's]

snufkin wrote on 2021-12-20, 20:36:

Sphere478 wrote on 2021-12-20, 20:30:

Switch 3 is bf Switch 2 is bf1 Switch 1 is nc (in line with other two pins) […]
Show full quote

Switch 3 is bf
Switch 2 is bf1
Switch 1 is nc (in line with other two pins)

Basically they flip orientation when looking head on a the three switches and pins.

I assume bf is bf0, bf1 is bf1 and nc is bf2

So what settings are required for 2x?

NC? It looks like switch 1-3 go to R6,7&8 (330 ohm). Seems unlikely they would fit all three resistors for one to be NC. Datasheet (I edited post just above yours earlier) says 2x/6x is BF[2..0] = 110b.

Nc is the label for the right most bf pin on the schematic I uploaded.

says 2x/6x is BF[2..0] = 110b.

I don’t understand

Edit, ohh! So we want bf 0,1 on and bf2 off?

Sphere478 wrote on 2021-12-20, 20:39:

Nc is the label for the right most bf pin on the schematic I uploaded. […]
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Nc is the label for the right most bf pin on the schematic I uploaded.

says 2x/6x is BF[2..0] = 110b.

I don’t understand

Edit, ohh! So we want bf 0,1 on and bf2 off?

Ah, missed that, I'd already downloaded a pinout that had them labeled BF2, BF1 and BF0.

Not sure how to describe this, but when giving the setting of a bus of several lines, like BF[2..0], the setting will be in the same order as given in the square brackets.
So BF[2..0]=abc means BF2=a, BF1=b and BF0=c. So BF[2..0]=110b (b for binary, would also make sense to give it in octal/hexdecimal) mean BF2 and BF1 set to '1' and BF0 set to '0'.