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Everex 486 dx2-66 with UM8886f (umc) motherboard. no ide hdd wants to boot. not even with ontrack partition. Thanks

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First post, by renejr902

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i bought a not really tested Everex 486 dx2-66. see the picture. i got it for 100$ in local pick-up while visiting the guy, i didnt buy it on ebay, but its the real one in picture that i bought. the guy removed the ebay ad after i bought it.

https://www.cafr.ebay.ca/itm/256079108504

First time i boot it black screen. i remove the cirrus logic isa video card and put a S3 pci video card.
The PC boot normally, but cmos battery dead but not leaking at all.

I tried maybe 10 ide hdd. 9 of them were detected in ontrack manager overlay but no one were detect with fdisk while booting with a 1.4mb disk in a:
Even ide hdd with correct booting parition made with another pc cant boot on this everex 486.
with 7 of them i tried to install ontrack manager. But very strangely ontrack manager overlay utility was very very slow for each step and for format, really slow, i didnt see that before in last years and i use ontrack manager overlay very often.

I tried different hdd size from 1.6gb to 80gb.
1.6gb were detected corrected in bios in auto detect.
For most hdd i use custom hdd parameter 1024 15 63 for 495mb. otherwise ontrack manager overlay didnt find any disk. with these parameter ilontrack manager overlay detect the ide hdd correctly.
I still succeed with each ide hdd to finished the ontrack manager partition, even if it was very very slow. But no ide hdd boot anyway. i can only boot from 1.44mb.

I tried ide slot 2 a lot and it doesnt work too.

Note: i dont think its the problem. But is it possible that dead cmos battery prevents the hdd to boot ?

My next idea is to disable integrated ide 1 and ide 2 with jumper and try a i/o card.

Thanks a lot for advice and help guys 😀

Reply 1 of 4, by BitWrangler

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With the 1.6GB in, when you reboot, does it try to redetect, or does it have it correct already in the system summary? Can you see it from Fdisk if you boot a DOS floppy?

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 2 of 4, by renejr902

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BitWrangler wrote on 2024-10-03, 02:05:

With the 1.6GB in, when you reboot, does it try to redetect, or does it have it correct already in the system summary? Can you see it from Fdisk if you boot a DOS floppy?

its detected correctly in bios, automatically without my help. But while booting it says: no booting operating system installed. But the booting blue screen show the 1.6gb detected in master ide 1

No. it cant see it with fdisk, while booting with floppy 6.22 with fdisk on the floppy disk

only ontrack manager see it and install partitions on it very very slowly like other hdd. its like ontrack manager froze for a few second before each step

Reply 3 of 4, by renejr902

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I disabled ide 1 and ide 2 with jumper.
I tried a multi i/o isa card. Same problem exactly
hdd were detected the same way, slow as ever with ontrack manager. fdisk didnt detect the 1.6gb hdd.
I changed ram. i change all cable. I tried the hdd test in the ontrack manager boot disk, hdd work great.
I made other tests with sysinfo too on a floppy disk.
no more idea.

I think the cmos dead battery prevent hdd from booting, i dont see any other possibility. I will remove the battery and put a socket with a new battery in a few days.

Thanks a lot for help and advices, its really appreciated.

While booting the pc show this, it should be the motherboard model

8810P AIO v2.1 27/1/1995

I think the everex desktop pc have the same motherboard than this one:

https://theretroweb.com/motherboards/s/ecs-um … 10p-aio-rev-2.x

Everything is exactly the same and same jumper function at same place.

It should be the battery i just read this on the last link:

Known issues:

DALLAS RTC coin cell empty
The motherboard's Real-Time Clock (RTC) chip contains a coin cell that may have drained, causing the loss of CMOS settings. This can result in an inability to save settings, causing system instability or failure to boot. To fix this, the RTC chip can be replaced with an equivalent or repaired by cutting into it and soldering on a new external coin cell holder.

Reply 4 of 4, by renejr902

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Everythings good 😀 We made a battery adapter and put a new battery in it and original ide hdd 1.6gb boots to dos. So some 486 motherboard dont boot without a valid cmos battery. Its my first time i saw this. See my pictures. Have a nice evening guys 😀

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