VOGONS


First post, by stinkydiver

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Hello fellow vogons

I booted up my Am486 DX4-100 for the first time in 12 months and was met with an unfortunate surprise. Up until now the system has been rock solid but on boot the system would not fully complete its POST ritual.

I power on the system, and it emits a single beep
It completes its memory test then...

It stalls at Press F1 to continue or Del to enter BIOS.

The computer does not respond to any keyboard inputs. I have tried 2 different keyboards and 2 different ps/2 to AT adaptors.

I've torn down the system to only a single stick of ram and the video card and that has made no difference.

The only thing I can suspect is a bulging capacitor near the cpu but I am not sure if that would cause such a problem. Could it be possible the keyboard controller has died?

The mother board is a ASUS VL/I-486SV2GX (see attached photos, ignore the empty battery socket)

Any ideas on what I can do?

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Take that there and put it in here

Reply 2 of 8, by AlexZ

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I would recommend to clear CMOS (I assume you added battery to the board). That capacitor is also a possible culprit however I would unsolder it only after ruling out other causes. I would try to hard reset it a few times when it hangs. Is CPU voltage set correctly? I'm afraid if you want a vintage computer you need to have a spare of everything to troubleshoot these issues. I don't think keyboard controller can die in a computer in storage for one year. If all other causes are ruled out and it still doesn't boot then a voltage spike from an old PSU may have killed it.

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Reply 3 of 8, by stinkydiver

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Doornkaat wrote on 2021-10-21, 07:12:

Did you check wether the keyboard gets stable +5V?

What do you know, I just tested with another power supply and it worked. So I will check the voltages on the original supply and report back

Take that there and put it in here

Reply 6 of 8, by stinkydiver

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I measured the voltages from the 4 pin moltex connectors and they were within range.

I went and tried the original power supply again and lo and behold... keyboard works

So maybe the fault is with the motherboard cap?

Take that there and put it in here

Reply 7 of 8, by canthearu

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Could just have been an iffy power connection.

With 12 months of non-use, connections could have become slightly corroded and not making good contact. Simply reconnecting it (with the same or a different PSU) may have been all it neede.

Reply 8 of 8, by stinkydiver

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I’ve noticed when entering the bios setup instead of showing the setup screen in one go it draws the interface line by line (although it only takes a few seconds).

Take that there and put it in here