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First post, by egbertjan

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I have an Asus pvi-486sp3. What is the best way to do a hard bios rest?

Reply 3 of 10, by Disruptor

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Pull the coin cell battery out of the mainboard?

What do you aim for?
Which error do you have?

If you have strange mainboard behavior (booting to boot block), try to replace EDO RAM by FPM RAM.

Reply 4 of 10, by spacesaver

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I need to do the same. For some reason, I can get into the BIOS by pressing delete, but after that, it doesn't respond to keys any more. Same if you boot to DOS. I think it's because I did "load BIOS defaults" earlier, which isn't the same as "load setup defaults"
I tried taking out the battery and removing the jumper from JP31 (Re: Asus 486 mobo PVI-486SP3 won't POST.) while powered off, but it still isn't resetting. I know because the floppy configuration stays at 2.88MB, which is what I set

Last edited by spacesaver on 2023-09-04, 07:59. Edited 1 time in total.

Reply 5 of 10, by spacesaver

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I tried taking out the battery and shorting the battery posts. Then on the next boot, it says CMOS checksum mismatch, loading defaults, but I can't proceed because it's not responding to the keyboard and it seems it doesn't save the restored values until you press F1. Ugh.

Reply 8 of 10, by spacesaver

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Actually, I'm not sure if "load BIOS defaults" triggered it. It was working right after I did it. I attached an oscilloscope to the data and clock lines and see normal clock activity when keys are pressed until the end of the mem test. Then the clock line stays at 0 almost all the time. The clock being pulled low means the host wants to send data to the keyboard (but there's very little activity on the data line) so the keyboard can't transmit. What could that mean? The keyboard works fine on another machine

Reply 9 of 10, by spacesaver

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It was a bad keyboard controller! I took a gamble and ordered a DIP socket and Amikey 2, but it paid off.
file.php?mode=view&id=174110

I wonder if the Amikey 2 is programmable. Then I might be able to reflash it with the image from the working chip.

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