GA-686LX Motherboard capacitor value (KBC Pin 40) \ VOGONS

GA-686LX Motherboard capacitor value (KBC Pin 40)

Topic actions

Post a reply

First post, by appiah4

Posted on 2021-05-02, 16:07

appiah4 Offline

Rank l33t++

Rank: l33t++
Posts: 9138
Joined: 2017-02-19, 07:36
Location: Sea of Sorrows

While desoldering a damaged ISA slot from my GA-686LX motherboard I accidentally damaged an SMD capacitor (I think).

The IC in question labelled BC1 is connected to Pin 40 (Vdd) of the KBC on one end and GND on the other. I need to replace it but have no idea what it is.

It's apparently a decoupling cap, but I don't know what the value should be. My gut feeling is something like a 0.1uF part, but I'd like to know if anyone can confirm..

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

Reply 1 of 2, by Horun

Posted on 2021-05-03, 02:57

Horun Offline

Rank l33t++

Rank: l33t++
Posts: 6023
Joined: 2019-09-19, 02:19
Location: USA

Sorry do not have that board and none match. Is that the SMD cap near the corner of the KBC ?
If so am sure near any low capacitance (less than 0.01mFD) would work. Closest is on a Pentium board with similar AMI-Key KBC and is a 104 (100nF) off the same pin.
Maybe someone else has a more similar board....

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 2 of 2, by appiah4

Posted on 2021-05-03, 07:33

appiah4 Offline

Rank l33t++

Rank: l33t++
Posts: 9138
Joined: 2017-02-19, 07:36
Location: Sea of Sorrows

Horun wrote on 2021-05-03, 02:57:

Sorry do not have that board and none match. Is that the SMD cap near the corner of the KBC ?
If so am sure near any low capacitance (less than 0.01mFD) would work. Closest is on a Pentium board with similar AMI-Key KBC and is a 104 (100nF) off the same pin.
Maybe someone else has a more similar board....

It is exactly as you describe, at the edge of the board next to the KBC and connected to Pin 40, and (I think) an 0805 package. This is enough confirmation for me, I'll just slap on a 100nF and see how that goes, thank you so much.

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

Go to top of page Go to top of page

Back to General Old Hardware

Main menu

Common searches