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Asus 486 mobo PVI-486SP3 won't POST.

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First post, by retro games 100

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PCB revision 1.2. I'm using a couple of sticks of single-sided FPM 16MB (32MB total) SIMMs. I've tried 2 different CPUs: an AMD DX4-100 (write back model), and also a Cyrix DX-40. At the moment, I've got no other SIMM memory available to test. Is this board/1.2 revision fussy about what memory you use with it? Any thoughts please?

The mobo's configuration is here -

http://stason.org/TULARC/pc/motherboards/A/AS … PVI-486SP3.html

However, my 1.2 revision board doesn't exactly match up with this configuration. For example, the 1.2 board has a button battery, instead of a real time clock block as featured in this stason webpage.

Also, the Asus manual is available here -

ftp://ftp.asus.com/pub/ASUS/mb/sock5/486sp3/ (for revision 1.1)

Reply 1 of 25, by retro games 100

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I managed to find my box of old RAM SIMMs. I tried half a dozen different sticks - either a single stick or a pair, and I can't get this board to POST. I tried 2 graphics cards, both were PCI. I wonder if I need to try the VESA slot, for the video? Also, I tried a 3rd CPU, this time a DX2-66. No joy. The board was supplied to me without a button battery, so I put a new one in. There's a jumper near the battery called JP31, which is closed. I wonder what it does, it isn't mentioned in the (PCB 1.1) manual. (This board is 1.2).

I even tried removing the BIOS chip, and replacing it with a chip from another Asus board - but this board is slightly different, it's a PVI-486AP4 board. Perhaps that wasn't a good idea.

Also, the BIOS jumpers are set to EEPROM. The manual says leave these jumpers on the default setting, which is not EEPROM. Strange.

Reply 2 of 25, by 5u3

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AFAIK jumper JP31 clears the BIOS settings when removed.

On my rev. 1.2 board the voltage regulator for 3.3V CPUs has failed and needed to be replaced. However, even if this also happened on your board, 5V CPUs should still work.

retro games 100 wrote:

Also, the BIOS jumpers are set to EEPROM. The manual says leave these jumpers on the default setting, which is not EEPROM. Strange.

You mean the JP32/JP33 jumpers? These determine the flash ROM voltage (5V/12V) and should be set according to the ROM chip used. The setting only matters when you write a new BIOS to the ROM.

Reply 3 of 25, by retro games 100

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I am looking at the mobo at this location: just south of the white PSU socket area, and one inch north from the top of CPU white socket area. There are 2 chips here, which appear to have mini "heatsinks" attached to them. Is this area connected with voltage regulation? One of these mini "heatsinks" (the one furthest away from the PSU socket area) looks ominously discoloured, almost as if it's been "burnt", or exposed to a high level of heat.

Reply 4 of 25, by 5u3

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retro games 100 wrote:

I am looking at the mobo at this location: just south of the white PSU socket area, and one inch north from the top of CPU white socket area. There are 2 chips here, which appear to have mini "heatsinks" attached to them. Is this area connected with voltage regulation? One of these mini "heatsinks" (the one furthest away from the PSU socket area) looks ominously discoloured, almost as if it's been "burnt", or exposed to a high level of heat.

Yes, that's the 3.3V CPU voltage regulator. Look here for a photo of my board after I replaced the converter (I admit the heatsink is a bit over the top 😉).

Do you have a "vanilla" 5V 486 to test in the board? The voltage regulator is only needed with 3.3V CPUs, the board should boot normally if you use a 5V processor.

Reply 5 of 25, by retro games 100

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Spectacular heatsink! 😁

Regarding a "vanilla" 5V 486 CPU: I currently have an Intel DX/2-66 CPU in it; code SX911. I think this is a 5V CPU. SL enhanced=Yes, Writeback cache=No.

Is this SP3 mobo fussy about what SIMMs you can use with it? Would 1 (or 2) stick(s) of single-sided FPM be OK? (I have a pair of them, and used them successfully in an Asus AP4 mobo.)

Thanks a lot for any additional comments.

Edit: Recently, I bought an Intel 486SX-25 CPU. It is not enhanced, and has no writeback. So, quite basic. I hope it will arrive sometime this week. I will try it in the SP3...

Reply 6 of 25, by 5u3

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SX911 is a 5V model.

The PVI485SP3 is not particularly picky about RAM, except that it doesn't run with EDO modules. With EDO RAM inserted, mine shows a garbled screen instead of the BIOS screen and crashes.

More troubleshooting: Do you have a beeper connected? There should be error beeps when you start the board without RAM or video card. If it doesn't beep, there is something wrong with the power or the BIOS.

Reply 7 of 25, by retro games 100

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I have just attached a "mobo testing kit" speaker to the mobo's speaker pins. All tests below produced no sound:

Both video card and RAM inserted.
Video card removed. RAM inserted.
Video card removed and RAM removed.

Also, I have tried booting with and without the HDD/FDD plugged in to the mobo's integrated IO pins.

I am using an ATX PSU (no -5V rail), with an ATX to AT PSU adapter. This works OK on my other 486 mobos. I've had good success with these ATX to AT PSU adapters.

I could remove the non -5V ATX PSU, and replace it with a -5V ATX PSU.....?

Edit: I just tried another combination:

-5V PSU with just the video card. Again, no sound. The seller shipped the mobo to me without a button battery in it. Perhaps it wasn't tested?

Reply 8 of 25, by Amigaz

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Proof it works
http://cid-1fa95f4397ce8214.skydrive.live.com … 486sp3%5E_2.m4v

Either jumpers are set wrong, wrong type of RAM

My retro computer stuff: https://lychee.jjserver.net/#16136303902327

Reply 9 of 25, by retro games 100

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Amigaz wrote:

Proof it works
http://cid-1fa95f4397ce8214.skydrive.live.com … 486sp3%5E_2.m4v

Either jumpers are set wrong, wrong type of RAM

In that video, you're using a type of graphics card I haven't seen before. I'm guessing it's an ISA card. Unfortunately I don't have any ISA graphics cards. However, I might be able to test this mobo with a VLB graphics card in the next couple of days.

I'm almost positive the jumpers are correct, because I've double-checked them many times. Also, the RAM should be fine. I've tried about 10 different types, none of which are EDO.

Reply 10 of 25, by Tetrium

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retro games 100 wrote:
Amigaz wrote:

Proof it works
http://cid-1fa95f4397ce8214.skydrive.live.com … 486sp3%5E_2.m4v

Either jumpers are set wrong, wrong type of RAM

In that video, you're using a type of graphics card I haven't seen before. I'm guessing it's an ISA card. Unfortunately I don't have any ISA graphics cards. However, I might be able to test this mobo with a VLB graphics card in the next couple of days.

I'm almost positive the jumpers are correct, because I've double-checked them many times. Also, the RAM should be fine. I've tried about 10 different types, none of which are EDO.

The graphics card is indeed ISA.
This is proving to be a hard nut to crack...

Have you checked the mobo for any broken traces? (deep) scratches and the like? Could it have any loose solder joints?
Long shot: Have you tried both parity and non-parity FPM simms?

Edit: You could try disabling and/or removing the onboard cache! That could be worth a try.

Last edited by Tetrium on 2010-04-13, 09:31. Edited 1 time in total.

Reply 11 of 25, by Amigaz

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retro games 100 wrote:
Amigaz wrote:

Proof it works
http://cid-1fa95f4397ce8214.skydrive.live.com … 486sp3%5E_2.m4v

Either jumpers are set wrong, wrong type of RAM

In that video, you're using a type of graphics card I haven't seen before. I'm guessing it's an ISA card. Unfortunately I don't have any ISA graphics cards. However, I might be able to test this mobo with a VLB graphics card in the next couple of days.

I'm almost positive the jumpers are correct, because I've double-checked them many times. Also, the RAM should be fine. I've tried about 10 different types, none of which are EDO.

Yeah, it's an 8bit ISA VGA card

The CPU I'm using is a intel 486DX2 66mhz 5volt CPU
The ram is a double sided 8meg FPM stick

Have you tried with a different PSU?

My retro computer stuff: https://lychee.jjserver.net/#16136303902327

Reply 12 of 25, by retro games 100

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Amigaz wrote:
Yeah, it's an 8bit ISA VGA card […]
Show full quote
retro games 100 wrote:
Amigaz wrote:

Proof it works
http://cid-1fa95f4397ce8214.skydrive.live.com … 486sp3%5E_2.m4v

Either jumpers are set wrong, wrong type of RAM

In that video, you're using a type of graphics card I haven't seen before. I'm guessing it's an ISA card. Unfortunately I don't have any ISA graphics cards. However, I might be able to test this mobo with a VLB graphics card in the next couple of days.

I'm almost positive the jumpers are correct, because I've double-checked them many times. Also, the RAM should be fine. I've tried about 10 different types, none of which are EDO.

Yeah, it's an 8bit ISA VGA card

The CPU I'm using is a intel 486DX2 66mhz 5volt CPU
The ram is a double sided 8meg FPM stick

Have you tried with a different PSU?

I've tried the mobo with the same CPU as yours, and also I've just tried a 2nd PSU. The only thing I need to ensure is that I correctly identify and then use a double sided FPM stick. I must have one, because I've got a box with dozens of 72pin sticks. But the problem is correctly identifying one. I guess I need to look for the words 36 rather than 32. So for 8MB, something like this: 2M x 36. (And also, nothing to do with EDO.) Many sticks have the number 6 or 7 written on them. Do I avoid all sticks with the number 6?

Reply 13 of 25, by retro games 100

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Tetrium wrote:
The graphics card is indeed ISA. This is proving to be a hard nut to crack... […]
Show full quote
retro games 100 wrote:
Amigaz wrote:

Proof it works
http://cid-1fa95f4397ce8214.skydrive.live.com … 486sp3%5E_2.m4v

Either jumpers are set wrong, wrong type of RAM

In that video, you're using a type of graphics card I haven't seen before. I'm guessing it's an ISA card. Unfortunately I don't have any ISA graphics cards. However, I might be able to test this mobo with a VLB graphics card in the next couple of days.

I'm almost positive the jumpers are correct, because I've double-checked them many times. Also, the RAM should be fine. I've tried about 10 different types, none of which are EDO.

The graphics card is indeed ISA.
This is proving to be a hard nut to crack...

Have you checked the mobo for any broken traces? (deep) scratches and the like? Could it have any loose solder joints?
Long shot: Have you tried both parity and non-parity FPM simms?

Edit: You could try disabling and/or removing the onboard cache! That could be worth a try.

The mobo does not appear to have any physical defects. Regarding the parity/non-parity FPM SIMMS: this is where I get confused. I don't know how to visually identify old 72pin RAM. I have a box of sticks, and I can only correctly identify the EDO RAM, because these sticks have the word EDO written on them. As for all of the other sticks, it's just a mystery to me what type they are. Is there any internet webpage that can show photos of the different types of 72pin RAM? Many of the sticks have lots of numbers on them, but this does not assist me with identifying their type. Thanks a lot to anyone offering any clues...

Reply 14 of 25, by Tetrium

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retro games 100 wrote:
Tetrium wrote:
The graphics card is indeed ISA. This is proving to be a hard nut to crack... […]
Show full quote
retro games 100 wrote:

In that video, you're using a type of graphics card I haven't seen before. I'm guessing it's an ISA card. Unfortunately I don't have any ISA graphics cards. However, I might be able to test this mobo with a VLB graphics card in the next couple of days.

I'm almost positive the jumpers are correct, because I've double-checked them many times. Also, the RAM should be fine. I've tried about 10 different types, none of which are EDO.

The graphics card is indeed ISA.
This is proving to be a hard nut to crack...

Have you checked the mobo for any broken traces? (deep) scratches and the like? Could it have any loose solder joints?
Long shot: Have you tried both parity and non-parity FPM simms?

Edit: You could try disabling and/or removing the onboard cache! That could be worth a try.

The mobo does not appear to have any physical defects. Regarding the parity/non-parity FPM SIMMS: this is where I get confused. I don't know how to visually identify old 72pin RAM. I have a box of sticks, and I can only correctly identify the EDO RAM, because these sticks have the word EDO written on them. As for all of the other sticks, it's just a mystery to me what type they are. Is there any internet webpage that can show photos of the different types of 72pin RAM? Many of the sticks have lots of numbers on them, but this does not assist me with identifying their type. Thanks a lot to anyone offering any clues...

I can help you with that 😉

It's real easy to identify parity from non-parity, you only need to look at the number of chips.
Memory sticks with an even amount of chips (or better yet, with a number equal to the power of 2, so 2,4,8,16,32 etc) are non-parity and ones with an uneven number (usually) of chips are parity.

So sticks with say 4, 8 or 16 chips are all non-parity and sticks with say 3, 9, 18, 24 or 36 chips are parity.

Parity memory is basically the foreruner of ECC memory.

Lemme find some pics on teh internet...

Edit: Heres some more in dept info on parity:
http://en.wikipedia.org/wiki/Memory_Parity

This page has some nice pics also:
http://damieno.com/sites/MGVwebsite/mem_basics.html

This is what a typical parity module looks like:
72pin.jpg

This is what a typical non-parity module looks like:
72pin1.jpg

Hope this helps 😉

Have you checked my hint on the motherboard cache yet btw? I'm interested wether it works or not

Last edited by Tetrium on 2010-04-13, 13:35. Edited 1 time in total.

Reply 15 of 25, by retro games 100

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Thanks very much. 😀 In the meantime, here's some pics of my old RAM. Can you spot anything which might be useful to try? Also, I am a bit worried that the BIOS is "broken" somehow. The reason is because I hear no beeps from the speaker. I think the PSU is OK.

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Reply 17 of 25, by retro games 100

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Tetrium wrote:

Hope this helps 😉

Have you checked my hint on the motherboard cache yet btw? I'm interested wether it works or not

Awesome, thanks.

ATM, I'm a little bit reluctant to pull out the 9 cache chips, because I always bend the back legs when I pull these type of chips from a mobo. I would like to replace the single BIOS chip first, before attempting to do anything with the cache chips.

I notice in the testing vid, that the stick of RAM used has 8 chips. Also, this is a very long shot, but is there a very minor possibility that if you test a mobo without a battery in it, the BIOS could potentially become a bit "confused" and then put itself in to a kind of non operational state? Just guessing here!

Reply 19 of 25, by Tetrium

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h-a-l-9000 wrote:

> the BIOS could potentially become a bit "confused" and then put itself in to a
> kind of non operational state?

Yes, that's possible.

Oi, I've tested countless motherboards without the battery installed. Important is that you do not ever power on a motherboard with it's jumpers set to clear CMOS!

Just leave the cache chips in, you could try and configure the jumpers to 0kb cache. If I'm correct, the motherboard will then not check the cache, even if it is in fact installed. Please correct me if I'm wrong, I never tried this myself!