retro games 100 wrote:

Does anyone have some tips on how to get this mobo to show any sign of life? […]
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Does anyone have some tips on how to get this mobo to show any sign of life?

I DL'd the manual from the Asus website, then set up jumpers for both an Intel 486 SX-33, then an Intel 486 DX2-66. No POST. Then I tried about 6 different sticks of RAM. No POST. The cache is jumpered for 256k, but the TAG slot is empty. Is this a problem? I've tried all 3 PCI slots for my Trio64v+ graphics card. No POST. 😢

The mobo looks in good condition - no visible signs of damage. It's a pity that I don't have an ISA-based graphics card. I was wondering whether the cluster of IRQ jumpers on the board need to be set for a PCI-based graphics card?

I'm going to dig out another PCI graphics card and try that soon...

I remember mine was very picky about RAM, it would only boot with a couple of 100% 32mb double sided FPM sticks

Check the manual again, I don't have it right in front of me but I suspect you're using the wrong type of ram/in the wrong sockets, wrong jumper settings

Amigaz, you are a shining beacon in the murky world of retroland. 😉 As luck would have it, I have two sticks of double sided FPM sticks. Bingo! It's alive!! 😁 Cheers ears! 😀

retro games 100 wrote:

Amigaz, you are a shining beacon in the murky world of retroland. 😉 As luck would have it, I have two sticks of double sided FPM sticks. Bingo! It's alive!! 😁 Cheers ears! 😀

Glad to be of assistance 😁

May god speed you in your further quests with this fine Asus motherboard 😎

I have heard about this asus motherboard before. What makes it so good? Besides the fact that asus made it. 😁

2Mourty wrote:

I have heard about this asus motherboard before. What makes it so good? Besides the fact that asus made it. 😁

According to old magazine tests, the Intel Saturn/Aries chipsets offer the best PCI performance, but this seems to be a myth.

Usually 486 boards with 72-pin memory slots will start with only one SIMM installed, but the PCI/I-486SP3G (and other Saturn boards) needs two, because of a chipset feature called "memory interleaving", which is a bit like today's "dual channel" RAM access, but nowhere as efficient.

I once had a PCI/I-486SP3G, but it was half dead and the performance was rather unimpressive. Since the chipset is from Intel, support for other CPUs is poor, and it doesn't have a 40 MHz FSB setting (which is very nice to have on a 486 board).

2Mourty wrote:

I have heard about this asus motherboard before. What makes it so good? Besides the fact that asus made it. 😁

What makes it "good" is that it's easy to work with..good documentation and layout as usual on Asus mobo's
But as 5u3 says the performance isn't staggering, but it's better than on it's borother AP4 and as fast as the PVI 486SP3...and it's very stable
The built in SCSI-2 on the mobo isn't a screamer either...but it does it's job and is way better than the built in IDE
I used an Evergreen am5x86 133mhz upgrade cpu on mine..but it didn't give top notch performance..I guess the chipset is a big bottleneck for the cpu

An interesting problem has occured. In "pure DOS" only, the mobo cannot detect the presence of an ATAPI CD-ROM drive. However, inside Windows 98, there is no problem with the CD-ROM drive detection. The hardware being used is -

PCI #1 : Graphics card (BIOS IRQ set to 11)
PCI #2 : IDE HDD controller (BIOS IRQ set to 14 & 15, and using 1 HDD only ATM)
PCI #3 : empty, but the adjacent ISA slot #1 is being used for...

ISA #1 : CD-ROM controller card (controller card's IRQ jumper is set to 12)

Windows 98 seems happy with the above "arrangement", but "pure DOS" is unable to detect the CD-ROM drive.

Any ideas please people? 😀

retro games 100 wrote:

An interesting problem has occured. In "pure DOS" only, the mobo cannot detect the presence of an ATAPI CD-ROM drive. However, […]
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An interesting problem has occured. In "pure DOS" only, the mobo cannot detect the presence of an ATAPI CD-ROM drive. However, inside Windows 98, there is no problem with the CD-ROM drive detection. The hardware being used is -

PCI #1 : Graphics card (BIOS IRQ set to 11)
PCI #2 : IDE HDD controller (BIOS IRQ set to 14 & 15, and using 1 HDD only ATM)
PCI #3 : empty, but the adjacent ISA slot #1 is being used for...

ISA #1 : CD-ROM controller card (controller card's IRQ jumper is set to 12)

Windows 98 seems happy with the above "arrangement", but "pure DOS" is unable to detect the CD-ROM drive.

Any ideas please people? 😀

You have it hooked up to the IDE on the mobo?
These old IDE I/O stuff is very picky that you follow the ancient "nazi" standard that you have you master device at the middle IDE connector and the slave at the end connector.
Try junpering the cd-rom to cable select, if it doesn't work try another cd-rom drive

I decided to abandon using both the PCI-based IDE HDD controller card, and also the ISA-based IDE CD-ROM controller card. Instead, I plugged an old HDD directly on to the mobo's onboard IDE controller, using an old 40 pin cable. I connected the cable's middle master connector to the HDD, and also set the HDD's jumper to master. Then, I connected the ATAPI CD-ROM drive to the end of this cable, using the end slave connector. I also set the CD-ROM's jumper to slave setting. This all works.

It's interesting, because when "pure DOS" detects the CD-ROM drive, it states: "Programmed I/O" mode. I guess the mobo's BIOS only understands this mode, and not UDMA? This could be why my previous tests were failing. In these tests, I had connected the CD-ROM drive to a 16-bit ISA-based CD-ROM controller. My guess is that this controller card was trying to use UDMA mode, and the mobo wasn't happy about it. Just a guess.

Edit: Actually, I'm not sure if my guess above is right. Perhaps this test failed for another reason. I notice the mobo only has 1 onboard IDE header (because the other header is a SCSI connection). Maybe on this specific mobo, you can only have 1 master IDE device, and 1 slave IDE device? My previously unsuccessful test had 1 master IDE HDD, and also 1 master IDE CD-ROM drive. I'll retry this test, but set the IDE CD-ROM drive to slave, even though I'll plug it in to its own ISA-based CD-ROM controller.

Edit 2: I think I was right! (Wow, that's a first!) I set the CD-ROM device to slave, even though it was plugged in to its own controller, on its own, and effectively had no master device. It worked. "Pure DOS" detected the CD-ROM device, and stated "Programmed I/O" as before, for its mode of operation.

I knew it would work 😉

My guess is that your PCI card is PCI 2.1 or something and your mobo only is PCI 2.0 standard

Aargh! Stop the wild guesses! You're getting it wrong! 🤣

Wikipedia article on ATA

It's a long read, because the ATA interface is a rather chaotic "standard", especially with old drives/controllers.

Here is a list of things to consider:

• Putting multiple IDE controllers in one machine is only a good idea if you sort out the resources they use. Many ISA/VLB controllers default on the standard resources (1F0/3F6H, IRQ 14; 170/376H, IRQ15), so watch out for conflicts! PCI/ISAPnP controllers can be a pain to set up with ancient and buggy 486 PnP BIOSes.
• According to the ATA standard, the master drive is connected to the end connector and the slave drive to the middle connector, not the other way round. The position is only relevant when using the "cable select" jumper setting on both drives. It shouldn't matter when you set the jumper to master/slave directly. Some old drives don't conform to the standard and may not work in certain configurations (this caused major headaches in the mid-90s).
• Older DMA modes (Single/Multiword DMA, sometimes called "block mode") might be supported by older ISA/VLB and onboard controllers, but they were considered as unreliable, since they don't offer error correction. The biggest chance to use these modes is with chipset-integrated mainboard controllers.
  Ultra-DMA was introduced when PCI had been mainstream for quite some time, so only PCI cards support it. It relies on some more advanced PCI features, so forget about them if you have a 486 board.

My guesses regarding the slave/master stuff has some thruth in it since it's the only way I've gotten many of my 386 and 486 setups working...don't ask me why my "non standard" methods has worked 😵

This matters only if you use some special kind of cable. With a normal cable it can't tell the difference.

Hmm, very old cables actually were wired the other way round. Instead of omitting pin 28 at the middle connector, they had a cut wire between the middle and the end connector.
However, there's one possible problem with this setup: IDE cables don't have terminators. If you have only one device connected to the middle connector, the unconnected end causes signal reflections. This is no problem at slow transfer modes, but can cause errors in the faster ones.

@5u3, thanks very much for your valuable information. In future, I will be more careful with my silly guesses.

@Amigaz, thanks for the PCI 2.0 info - it's useful to know that the board doesn't cover the 2.1 standard.

During my testing, I spotted an interesting side effect. If you launch a "pure DOS" session from the win98 desktop, so that it reboots in to DOS, the CDROM drive door will not open, no matter how many times you press its eject button. However, if you bypass windows 98 entirely by booting from a win98 diskette, or if you disable the ISA-based IDE CDROM controller driver inside windows 98, then reboot to DOS, the CDROM eject button works fine. Curious.

5u3 wrote:

Hmm, very old cables actually were wired the other way round. Instead of omitting pin 28 at the middle connector, they had a cut wire between the middle and the end connector.
However, there's one possible problem with this setup: IDE cables don't have terminators. If you have only one device connected to the middle connector, the unconnected end causes signal reflections. This is no problem at slow transfer modes, but can cause errors in the faster ones.

Whats a signal reflection, is there nay fix like a better cable?

The fix is not to use those old cables 😉

Signal reflection occurs when a signal bounces back from the end of an unterminated cable, generating echos of the original signal.
Also, long wires not connected to anything act as antenna for electromagnetic interference, which is generated by the other PC components.

Some IDE cables are the perfect example for provoking this.
In order to avoid trouble with IDE setups, consider these points:

• Use only standard cables not exceeding a length of 18 inches (46 cm).
• When plugging only one drive to the IDE cable, make sure to connect it to the end connector.
• 80-wire cables work on any old IDE setup and offer the best signal quality. Also, old cables often have become brittle or otherwise damaged.
• On some old chipsets, the higher transfer modes were buggy. Don't use them if your drive isn't fast enough to actually make use of the higher bandwith.
• The IDE/ATA standard was poorly defined in the early years, so many old harddisks and CD-ROM drives are not fully compatible. This often results in two specific drives not wanting to work together on the same IDE channel.