VOGONS


First post, by RBretrox

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A Socket 370 motherboard forms the base of my Windows 98 project PC, but its got a problem that I can't find an answer to and I've tried everything I can think of/

Motherboard is a QDI Advance 9 Motherboard (Award BIOS), with ISA/PCI/AGP slots and USB ports - so its a very useful board for this type of project. Pentium III 800 CPU.

When I start the machine it does the normal POST Beep, then starts a continuous string of fast repeating beeps from the internal PC speaker. Windows will boot ok.

In the BIOS it reacts very slowly to keypresses, like a few seconds delay to each, the beeping continues. Sometimes the beeping is broken up, like a floppy disk access pattern sound (its not disk access). This is most often like a fast string of short "ticks" but also the normal high pitched beep at the same time.

It sounds like a stuck keypress, but it happens with any keyboard, even without one attached.

Also PS/2 ports are not working. USB keyboard works.

Things I've tried:

  • Different PS/2 keyboards and mice
  • Unplugging everything except RAM and CPU
  • Different RAM, Video Card, PSU
  • Updated BIOS successfully
  • Desoldered the PS/2 ports (in case it was a short on that)
  • Tested two small fuses on the board (continuity good)
  • Tried different HDDs
  • Checked for bottom of board shorts on the case
  • Checked voltages and temperatures in the BIOS - all ok

Can anyone suggest a cause and possible solution to this?

Thanks in advance!

Reply 3 of 29, by RBretrox

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wiretap wrote on 2020-02-03, 12:47:

Did you try desoldering the speaker? 😜

Just unplugging the speaker is a perfect solution to that crazy noise, but the slow bios responsiveness will still be there and I think it's causing problems in Windows/DOS too relating to keyboard and crashes.

Got to solder the PS/2 ports back on, but they came off very cleanly thankfully.

Reply 4 of 29, by RBretrox

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derSammler wrote on 2020-02-03, 10:57:

Fan alarm maybe?

I did think if it could be this

The CPU fan is spinning ok, CPU temperature seems ok too.

No other fans connected to the motherboard

It's not overheating according to temperatures in BIOS and there's no top on the case during this testing

Reply 5 of 29, by RBretrox

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I sometimes get a small static shock off the inside of the case when it's on. Not common, but it does happen.

At first I tried to swap the PSU, isolated the bottom of the board from the case, swapped the power cable, it still happens rarely

However, I'm usually sat on this shiny smooth plastic chair that I'm convinced gives me a static charge, when I slide off it to go and unplug some cable in the machine. Could be that, as my son knows too well when I give him a shock when he's playing a game on a computer next to me!

Reply 6 of 29, by RBretrox

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I'm waiting on another CPU and stick of RAM to arrive to rule those out

I will also try one of those cheap PCI diagnostic cards to see how that reacts.

Maybe even try another monitor

I'll try anything I can think of

Reply 7 of 29, by appiah4

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Your PSU is probably not giving it -5V because it lacks the -5V rail as it was removed from the ATX standard in 1.2 (?), try finding an older PSU with a -5V (white) rail. You can possibly eliminate this by going into the BIOS and checking out PC Health / Status Monitoring etc. options and disabling monitoring of voltages if there is such option.

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 8 of 29, by RBretrox

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Thanks, I'll check the -5V out tonight. I'm fairly sure that the voltage all looked ok in the BIOS and there didn't seem to be options for disabling warnings.

Its a fault that causing a slow down in the BIOS and also causing that rapid error clicking/beeping from the pc speaker, so turning off a warning may not solve it.

I'll report back

Reply 9 of 29, by appiah4

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RBretrox wrote on 2020-02-03, 13:53:

Thanks, I'll check the -5V out tonight. I'm fairly sure that the voltage all looked ok in the BIOS and there didn't seem to be options for disabling warnings.

Its a fault that causing a slow down in the BIOS and also causing that rapid error clicking/beeping from the pc speaker, so turning off a warning may not solve it.

I'll report back

I've had a very very similar problem in the past and it was -5V. Check it.

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 10 of 29, by RBretrox

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In the System Monitor part of the BIOS it shows voltages for:

VCCVID(CPU)
VTT(+1.5V)
+3.3V
+5V
+12V
-12V
VBAT
5VSB

All values seem ok

No mention of -5V

The PSU is from 2005 and shows -5V , 0.8A on the label.

Reply 12 of 29, by Horun

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RBretrox wrote on 2020-02-02, 19:37:
When I start the machine it does the normal POST Beep, then starts a continuous string of fast repeating beeps from the internal […]
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When I start the machine it does the normal POST Beep, then starts a continuous string of fast repeating beeps from the internal PC speaker. Windows will boot ok.

  • Different RAM, Video Card, PSU

Can anyone suggest a cause and possible solution to this?

Thanks in advance!

I have had that happen twice, once was dirty ram socket the other was faulty video card though got good image on monitor. You say you swapped both out so you might try cleaning the ram sockets with IPA and also try a PCI video card to eliminate issues with the AGP slot.
Added: the only other thing comes to mind: could be something awry around the I/O controller chip that handles the PS2 port (bad cap, loose solder joint, etc)

Last edited by Horun on 2020-02-03, 23:28. Edited 1 time in total.

First computer was an IBM 3270 workstation with CGA monitor. 🤣

Reply 13 of 29, by SirNickity

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RBretrox wrote on 2020-02-02, 19:37:

In the BIOS it reacts very slowly to keypresses, like a few seconds delay to each, the beeping continues. Sometimes the beeping is broken up, like a floppy disk access pattern sound (its not disk access). This is most often like a fast string of short "ticks" but also the normal high pitched beep at the same time.

It sounds like a stuck keypress, but it happens with any keyboard, even without one attached.

Also PS/2 ports are not working.

It's your PS/2 interface. On older boards, you could trace all that stuff back to the keyboard controller, but on a S370 board, it'll be on the Super I/O chipset. Look for a PS/2 port pinout online and make sure you're getting +5V where you should. You should also get +5V on the clock and data pins unless they're sending something. There are pull-up resistors connected from those to the +5V rail. If you get 0v, or substantially not +5V, then either there's an issue with the circuit somewhere, you have a jumper that enables PS/2 voltage and it's not set correctly, or your Super I/O chip is shot. You might be able to get around this by disabling PS/2 in the BIOS if it works OK otherwise.

Reply 14 of 29, by RBretrox

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Some good advice on more items to check. Thank you for the help so far.

There are 4 capacitors near the CPU socket, 1500uF ones. They look ok but the tops have some thing grey marks on them, compared to all the others. Not bulging, no leaks top or bottom (can see under).

Is it worth changing these?

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Reply 15 of 29, by bofh.fromhell

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RBretrox wrote on 2020-02-04, 17:18:
Some good advice on more items to check. Thank you for the help so far. […]
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Some good advice on more items to check. Thank you for the help so far.

There are 4 capacitors near the CPU socket, 1500uF ones. They look ok but the tops have some thing grey marks on them, compared to all the others. Not bulging, no leaks top or bottom (can see under).

Is it worth changing these?

IMG_20200201_134118_1~2.jpg

If you are comfortable doing it and you think the MB is worth it.
They are probably OK tho.

But I'd check for shorts, especially in and around the rear connectors and in (and under) the expansion sockets.
Or missplaced/missing jumpers.
And if work previously have been done on this MB check for flux residue and/or bad solderjoints.
A thorough clean of the entire board might also be a good idea (dish soap and warm water and dry in the oven at 50C or so then soak the BGA chips in IPA to remove any stubborn water).
You have tried the MB outside a case?

Reply 16 of 29, by RBretrox

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Oh dear, it's got worse.....

I tried a new CPU and it did the same beeping

Turned it off and on again, then there was some buzzing, then the "magic" smell (burning) and turned it off.

Now it won't turn on at all, with either CPU and with 2 PSUs. Swapped the power cable, no effect.

The PSU fan doesn't spin either. Sometimes the CPU fan will try to turn a tiny bit then nothing happens.

So it's dead, but nothing looks burned or blown

It's some sort of short somewhere

Thinking about what can be done next. If it's fixing components then I can live with that as long as it's not too obscure a part

Reply 19 of 29, by RBretrox

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I didn't see any magic smoke, but it smelled like it!

Are the CET items in the photo attached the VRMs?

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I think these smelled a bit at the time, but don't appear to be burned out.

Is this something that could be swapped for replacements? Are they very specific parts or are there generic replacements? I'll do a search now.