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Shuttle Hot 433 won't POST

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Reply 60 of 76, by Gary.H

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So you reckon the Dallas chip is hosed or the Shuttle motherboard ?

Could the battery have leaked inside the Dallas and corroded the chip ?

I quite liked the look of the Necroware replacement Dallas with the replaceable coin cell. Is there somewhere you can buy them pre-built ?

Reply 61 of 76, by mkarcher

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It's difficult to tell whether the Dallas chip doesn't work as expected because it is broken, or because it isn't accessed correctly due to the mainboard being broken. If you have a POST card, you might want to take a look whether it displays garbage codes. Writing to an ISA POST card and writing to the Dallas chip is very similar from the mainboard's point of view. So if you get nonsensical POST codes, the main board likely has a problem severe enough to also fail to communicate to the Dallas chip.

Reply 63 of 76, by mkarcher

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Gary.H wrote on 2022-05-04, 23:24:

Ok - I don't have a POST card. They seem pretty cheap. Any recommendations ?

There is this very common PCI/ISA combination model with 8 LEDs and multiple integrated chips. It works just fine. There is an even cheaper knock-off of that card with just a single integrated circuit and only 3 LEDs. This cheap knock-off also works fine in PCI slots, but the ISA interface is incomplete and can not work properly at all. To make matters even worse, the ISA connector on this cheap knock-off is too short and can easily inserted in a misaligned way. There are reports of mainboards being killed by these cards due to shorting +12V to some logic pin. Avoid that knock-off!

Reply 64 of 76, by Gary.H

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POST tester arrived today.

From the description it sounds like I have this one:

" very common PCI/ISA combination model with 8 LEDs and multiple integrated chips."

It fits full length in the ISA slot so the only question now is which way to put it in the slot ?

An arrow on the tester card points to 'Rear'.

I assumed that meant 'rear of the motheboard' ie where the rear of ISA/PCI cards would sit.

Sound correct (before I plug it in) ?

Chinglish manual says it won't harm card or motherboard if it is inserted the wrong way round - but would rather do it right first time !

Reply 65 of 76, by Gary.H

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Looking at it again I think it may need to go in the opposite way ?

The manual says the chip side of the card should 'face the power pin' (?) and seeing as the PCI slot edge connector on the card can only be inserted one way into the motherboard, I assume it should be inserted into the ISA slot with the chip side of the card facing the same way as when it's inserted into the PCI slot...

....which is opposite way to what I first thought !

Reply 66 of 76, by mkarcher

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"Rear" is an ill-defined term. They mean the rear of the PC case, where the slot covers are located. But don't try to wrap your head around it. Use a different approach instead: The card needs to be inserted with the components on the same side as any other card of the same bus type. So just plug it in with the components located the same way as it would be on e.g. a sound card.

This "just like any other card" rule applies both for the ISA and the PCI connector on that card.

Reply 67 of 76, by Gary.H

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mkarcher wrote on 2022-05-12, 12:15:

"Rear" is an ill-defined term. They mean the rear of the PC case, where the slot covers are located. But don't try to wrap your head around it. Use a different approach instead: The card needs to be inserted with the components on the same side as any other card of the same bus type. So just plug it in with the components located the same way as it would be on e.g. a sound card.

This "just like any other card" rule applies both for the ISA and the PCI connector on that card.

Thanks - that's what I reasoned after having a proper think about it.

Irony is that if I follow the 'components on the right side' logic the 'rear' arrow on the card ends up pointing to the front of the motherboard - 🤣

Reply 68 of 76, by Gary.H

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Well - with the chips facing the normal way on the card it won't boot in any of the ISA slots.

Going back to my original idea and following the arrow pointing to the rear of the motherboard (so the card is effectively upside down in the slot) it now boots and displays the POST codes 😀

Now to check them all.

Reply 69 of 76, by Gary.H

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Seemingly nothing untoward reported from the POST check card.

Now in the process of desoldering the old Dallas 12887A chip and trying to select a replacement RTC chip.

Farnell have the 12887+

Is that a compatible replacement for my 12887A ?

Reply 70 of 76, by jakethompson1

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Gary.H wrote on 2022-05-30, 00:23:
Seemingly nothing untoward reported from the POST check card. […]
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Seemingly nothing untoward reported from the POST check card.

Now in the process of desoldering the old Dallas 12887A chip and trying to select a replacement RTC chip.

Farnell have the 12887+

Is that a compatible replacement for my 12887A ?

The + means lead-free, which is fine.
The "A" means the ability for a cmos reset jumper to clear the CMOS RAM. If your board has such a jumper, and you put in a plain 12887+, you will lose that functionality.
So you want a 12887A+.

Reply 71 of 76, by Gary.H

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jakethompson1 wrote on 2022-05-30, 00:42:

The + means lead-free, which is fine.
The "A" means the ability for a cmos reset jumper to clear the CMOS RAM. If your board has such a jumper, and you put in a plain 12887+, you will lose that functionality.
So you want a 12887A+.

Cheers dude !

Yes, my Shuttle MB does have CMOS reset jumpers.

Reply 72 of 76, by Gary.H

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Ok, so.....

  • Desoldered the old dead Dallas RTC chip with solder sucker, solder wick and flux
  • Cleaned off the flux with Flux-Off
  • Soldered on a DIP socket
  • Inserted new 2022 Dallas RTC chip into the socket
  • Powered back on

Noone was more surprised than me (given my ropey soldering skills) when it booted up and successfully saved the new 2022 date settings 😀 !

Only the corners of a couple of PCI and ISA slots were harmed in this ham-fisted effort - 🤣

It now reliably correctly recognises the Am5x86-P75 again.

The back-plate mounted CF IDE emulator is recognised (once I found a jumper and set it as the Master) since it actually remembers the BIOS settings changes I make.

So.....

The only remaining issue is that both the DOS 6.22 disc sets that I have seem faulty so I can't install DOS 🙁

I've tried two separate floppy drives, so assuming they're both not faulty then the issue seems to be the floppies themselves.

Does anyone have a known-good set of DOS 6.22 floppies I can borrow ? (hardly piracy as I already own two copies of DOS 6.22 😉 )

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Reply 76 of 76, by Gary.H

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Thanks - will check.

Still think I need another set of discs as the attempts to fix the two Disc 1's I have with Scandisk appears to have rendered them completely useless - which would fit with the prognosis of a faulty FDD controller 🙁