sizzlinbeef wrote on 2026-05-31, 17:17:

Yes, jumpering JV6 gets the correct 2.5v. […]
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Chkcpu wrote on 2026-05-30, 19:51:

First close only JV6 and check if you indeed get 2.5V Vcore. Then also close JV7 and check the voltage. Depending on how the JV6 […]
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First close only JV6 and check if you indeed get 2.5V Vcore.
Then also close JV7 and check the voltage. Depending on how the JV6/JV7/JV8 resistor network is connected, you will see the Vcore either go down or go up.
Repeat the experiment with all other JV6/JV7/JV8 combinations.

If the voltage goes up with more than one JV6/7/8 jumper closed, a final test with all three JV6/7/8 jumpers open may reveal the lower Vcore you want to find.

I hope this procedure is clear and I’m curious what you will find.

Happy testing,
Jan

Yes, jumpering JV6 gets the correct 2.5v.

6-7 closed 1.93v
6-7-8 closed 1.73v
7-8 closed 2.04v
6-8 closed 1.95v

Unfortunately I can't confirm any of these result in a working system. I tried booting this board before testing. Using default settings for a pentium MMX (I tried a 166, 200, 233), can't get the thing to post. No video output. Tried different VGA, RAM, deoxit on all slots, alcohol clean, etc. I think time has taken it's toll on something on the board. It may be related to getting 3.6v on the VIO transistor when it should be 3.3v with JV1 and 2 open and JV3 set to 2-3. It has been probably a decade since I last tried booting it, so not surprising.

Thanks for reporting your test values.
So a 2.2V setting was not among them, but you found a nice 2.04V setting for a K6-2+! 😀

I’m sorry to hear the board won’t boot. The CMOS backup battery inside the DALLAS or BENCHMARQ RTC chip is probably dead. This sometimes causes a board to stall early during the Power-On-Self-Test.
Do you have a POST analyzer card to see where the boot process hangs?

Cheers, Jan

Ciao Jan,
I wanted to let you know that I downloaded the BIOS version 2.0 that you provided me, but currently I can't try it, because I'm away for work, but I have the ZIDA 5SVA-E motherboard on the bench, so as soon as I have the opportunity to dedicate a few minutes to it, I'll upgrade the BIOS, then I could try other CPUs, currently there is a Cyrix MII 300 (233 MHz), but if I remember correctly, it is possible to select lower voltages, for AMD K6 CPUs from 2.2V for example, maybe it could be possible to get up to 2.0V, but I don't think you can select lower voltages, this I think is possible only after modifying the motherboard, which I wouldn't do anyway, not having this need.
Greetings 🖖

PC@LIVE wrote on Yesterday, 09:08:

Ciao Jan,
I wanted to let you know that I downloaded the BIOS version 2.0 that you provided me, but currently I can't try it, because I'm away for work, but I have the ZIDA 5SVA-E motherboard on the bench, so as soon as I have the opportunity to dedicate a few minutes to it, I'll upgrade the BIOS, then I could try other CPUs, currently there is a Cyrix MII 300 (233 MHz), but if I remember correctly, it is possible to select lower voltages, for AMD K6 CPUs from 2.2V for example, maybe it could be possible to get up to 2.0V, but I don't think you can select lower voltages, this I think is possible only after modifying the motherboard, which I wouldn't do anyway, not having this need.
Greetings 🖖

Ciao Elio,

Thank you for going to test the patched Zida 5SVA(-E) BIOS.
If you can test it with a K6-2+ or K6-III+ that would be great.
But there is no hurry, so take your time.

Earlier you found that this board uses a HIP6008CB controller, so by using the four JP9 jumpers, the Vcore can be set from 2.0V to 3.5V in 0.1V increments.

Pulling all JP9 jumpers OFF will generate 2.0V.
Placing jumper JP9/1-2 will add 0.1V
Placing jumper JP9/3-4 will add 0.2V
Placing jumper JP9/5-6 will add 0.4V
Placing jumper JP9/7-8 will add 0.8V

Using any combination of these 4 jumpers, all 16 Vcore settings from 2.0V to 3.5V can be made.
And of course the JP8 jumpers block must be at position 1-2 for dual-voltage CPUs.

Greetings, Jan

Chkcpu wrote on 2026-05-31, 19:47:

I’m sorry to hear the board won’t boot. The CMOS backup battery inside the DALLAS or BENCHMARQ RTC chip is probably dead. This sometimes causes a board to stall early during the Power-On-Self-Test.
Do you have a POST analyzer card to see where the boot process hangs?

Cheers, Jan

Interesting. I've had many dead Dallas rtcs, this particular one is an ODIN clone, but haven't heard of a dead one preventing a computer from posting. They've always just annoyingly lost the BIOS settings on reboot. I'll battery mod this one and see if that changes anything. I do not have a post analyzer board.