Pentium 5Z Motherboard Smoking!

[gatewayrepairs1985]

Hi all, and happy thanksgiving!

Just a few minutes ago, I was working on a Gateway 2000 Pentium P5-90 motherboard that has been completely dead for years. I had last powered it on around two years ago and got nothing displayed on the screen. I finally got around to troubleshooting it - I placed a POST card in the first PCI slot and powered on the motherboard. I used the original power supply for this machine. However, it started smoking! I quickly turned off the machine and observed the area where the smoke was emitting from. I have come to these forums for help - these two brown squares seem to be the culprit. The smoke was emitting from them. I have no clue what they are or what they do. Is there any chance I can save this motherboard? Pictures of the motherboard and the culprits of the smoking are attached.

Thank you in advance for any help provided!

 

[NeXT]

Those are inductors. It's wire wrapped around a core of some sort with nothing else and are normally used for noise filtering in regulated voltage circuits. They will always read dead-short because it's just a length of wire but if they are smoking either there is a voltage with a high frequency passing through and saturating the core to the point of it dumping energy as heat (unlikely) or that's the point of most resistance and something is shorted so hard it's trying to burn the wire out like a fuse.

 

[Chuck(G)]

If the PSU voltages measure correctly, then you've got a problem in the voltage regulator supply for the CPU. I'd probably start by checking the large diode near the inductor as well as any surrounding capacitors.

 

[gatewayrepairs1985]

Those are inductors. It's wire wrapped around a core of some sort with nothing else and are normally used for noise filtering in regulated voltage circuits. They will always read dead-short because it's just a length of wire but if they are smoking either there is a voltage with a high frequency passing through and saturating the core to the point of it dumping energy as heat (unlikely) or that's the point of most resistance and something is shorted so hard it's trying to burn the wire out like a fuse.

Ah, thanks for the info! I’ve never really had my Pentium boards fail before, so I’m new to troubleshooting this type of board. I really appreciate the reply!

 

[gatewayrepairs1985]

If the PSU voltages measure correctly, then you've got a problem in the voltage regulator supply for the CPU. I'd probably start by checking the large diode near the inductor as well as any surrounding capacitors.

Hi Chuck!
Thanks for the advice - that’s really helpful! The PSU is definitely good, so I’ll have to check what you recommended. Hopefully I’ll have time to get to it this week! Thanks for the reply!