MrCrocodile wrote on 2023-04-26, 00:22:

Hi Everyone, […]
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Hi Everyone,

Recently I bought a cheap Aptiva, it's a lovely looking case with K6-2 processor inside. Unfortunately it looks like it's dead.
After I power it on, the screen will show the Aptiva logo, however nothing else happens. Keyboard (which I'm sure is working) only blinks the light when I power on the computer, but then none of the lights stays on. The fan on the processor is not spinning, however when I touch the radiator it gets hot pretty quickly.

I disconnected all the drives to make sure that none of the cables causes a short circuit, it didn't help though.

Does anyone have an idea what might be the problem? Is it dead motherboard or a dead processor or both or something else. I'm not entirely sure about the motherboard because it has an integrated graphics card which gives some output, on the other hand the fan on the processor doesn't spin.

Welcome to Vogons 😀

May just be a dead processor fan - it will overheat quickly without one and likely cause a system hang. Do you have any other working fans you could direct at the processor before trying again?

Showing the Aptiva logo is great sign, it's actually pretty alive! Dead would be nothing happening when you press power, that'd be totally dead. Keyboard blinking indicates the PC is at least getting to the keyboard routines in the BIOS which is a good sign. Does pressing Caps Lock toggle the light? Yes = system is still listening, no = it's hung.

Do you have any other memory modules you could try? Do you have another fan or multimeter you could plug into the fan header to verify there's no fan power?

You could also plug in a PCI video card to verify PCI is working and the system knows to output there. Another keyboard with the same results could also be useful to rule out the keyboard.

I haven't personally encountered a dead CPU of this vintage. But there could be other issues preventing a successful boot.

Cosmic wrote on 2023-04-26, 01:06:

Showing the Aptiva logo is great sign, it's actually pretty alive!

This is really encouraging.

This is my first retro PC, and don't have many spare parts. Definitely don't have another CPU fan to try, however I have a multimeter and can measure the voltage. Actually I have another RAM module can try this one one as well. Pressing Caps Lock or Num Lock doesn't toggle the lights (they all stay turned off). I tried another keyboard and the result is the same.

There are no POST beeps either.

MrCrocodile wrote on 2023-04-26, 01:16:

This is really encouraging. […]
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Cosmic wrote on 2023-04-26, 01:06:

Showing the Aptiva logo is great sign, it's actually pretty alive!

This is really encouraging.

This is my first retro PC, and don't have many spare parts. Definitely don't have another CPU fan to try, however I have a multimeter and can measure the voltage. Actually I have another RAM module can try this one one as well. Pressing Caps Lock or Num Lock doesn't toggle the lights (they all stay turned off). I tried another keyboard and the result is the same.

There are no POST beeps either.

Does F1 work to enter setup? Or Tab to "show POST screen"? Indeed if this your first retro PC you may find yourself buying new parts to test and replace, but that's just part of the fun. 😀

Overall it looks like a pretty clean system. The Aptiva series is excellent and this will be a great retro system once it is working. The best one can do without spare parts is to unplug/disconnect everything you can and test different configurations to help narrow down the issue. Different combinations of hardware and cables will produce different results which can be useful for finding the issue. For example I've seen bad ATA cables that needed to be replaced even though they were fine visually.

In my experience the hardware doesn't usually flat out die unless it's an obviously leaking capacitor. It's usually some piece of hardware or cable that's not connected right or isn't supported, but it could be bad capacitors or MOSFETs too, and they don't always fail in an obvious way.

No speaker beep could be an issue, the beep is often a "OK, I completed POST" sound. You should at a minimum acquire a POST card (they're inexpensive) to see what the bus says.

The finding so far, I've just measured the voltage at the CPU fan header- it's 11.7V between GND and VDC and 100mV DC between GND and the third pin (which I guess is the control one). I'm not really sure what's the expected voltage on the third pin. I've also ordered a PCI POST card, however it will arrive the next week.

MrCrocodile wrote on 2023-04-26, 04:58:

The finding so far, I've just measured the voltage at the CPU fan header- it's 11.7V between GND and VDC and 100mV DC between GND and the third pin (which I guess is the control one). I'm not really sure what's the expected voltage on the third pin. I've also ordered a PCI POST card, however it will arrive the next week.

The third pin (yellow or white wire usually) it's for rpm monitoring (most of the times). Just try another fan with the same connector, if you have it (the size is not important) for the test. Leave the one that is not spinning disconnected until you find a replacement with the same size so it will not potentially damage something on the motherboard. Also new thermal paste (between the cpu and the heat sink) is recommended.

Update, I found a bigger fan, however with the same connector and it started spinning nicely! Now, the end result is the same, even if I place the bigger fan directly above the heatsink - the computer doesn't go past the IBM logo and there are not beeps. Which makes me think that because of the bad fan the processor got fried...

MrCrocodile wrote on 2023-04-26, 07:14:

Update, I found a bigger fan, however with the same connector and it started spinning nicely! Now, the end result is the same, even if I locate the bigger fan directly above the heatsink - the computer doesn't go past the IBM logo and there are not beeps. Which makes me think that because of the bad fan the processor got fried...

If that was the case, you would not had any picture on the screen. There is something else that is causing that behavior. Have you tried a clear cmos ?

You can start from here:
https://www.manualslib.com/manual/1244089/Ibm … page=104#manual

1) enter bios and check. change to default, deactivat the logo, to show the post and see where it hangs
2) replace memory
3) disk may be dead and stoping the boot, disconnect it and try
4) take out and re-set the cpu, take the opportunity to change the cooler paste

I had some time this weekend to play around. Still no success, however it looks like it isn't memory. After I changed the RAM stick there is no difference - only the logo is shown after I turn the computer on. I also replaced the cmos battery, the old one was completely flat. This didn't change anything. The only thing that makes a difference is removing memory altogether, then there is no display output and the computer keeps beeping. Now I'm waiting for the POST diagnostic card I ordered earlier this week. I don't think I can make any further progress without it.

What type of keyboard do you use? Is it ps2 or usb?

This isn't the keyboard, I have a ps/2 keyboard that I verified.

Today I received a POST PCI card which I plugged in and the POST code it showed was 50 FF. This is the Award BIOS and the most descriptive error explanation I found is this:
Write all the CMOS values currently in the BIOS stack areas back into the CMOS. Write CMOS; Write all CMOS values back to RAM and clear screen.

I tried to google what is a reason for this failure but couldn't find much. Does anyone have an idea what is the reason?
I replaced the BIOS battery a couple days ago.

Update: It's working!

I took out the ram, cleaned the slot and the pins on the RAM stick, removed the CMOS battery and bended the top handle so it touches the battery with more pressure and removed the modem that was installed in one of the PCI slots. It booted to the BIOS!

I thought that was probably the battery that didn't properly power the CMOS RAM so I removed it and put the modem back. It stuck on the logo screen again. Then I put the battery back and again it was stuck! I removed the modem and it booted again! Which makes me think it's actually the modem causing troubles.

If I have any more findings I'll update this thread. I wanted to thank everyone who helped me to troubleshoot this computer!

When trouble shooting, always remove the 'non essential' cards. I assumed from your first picture that you had nothing else plugged in the slots. Glad to hear it works!