Hi Everyone, I recently built a 486 machine after getting my hands on some retro components which really got the nostalgia furnace going. I used a LS486E Rev. D motherboard, but have stumbled upon either some weirdness in the motherboard or there is an error in the manual provided at http://motherboards.mbarron.net/models/486pci/ls486ed.htm.

I received the motherboard with a jumper over the pins indicated in the manual as being turbo mode. However, in the finished system I found the turbo button had no effect on performance, and the turbo LED was glowing faintly regardless of whether the button was depressed or not. After some experimentation I found that bridging the pins labelled in the manual for the LED resulted in turbo being deactivated. Regardless of the turbo state though, the pins labelled for the button produced no voltage sufficient for an LED (intermittently 120mV).

Has anyone else experienced this on this revision of the board, or have conflicting information to that in the link I provided? I suspect a current limiting resistor may have burned out due to the LED pins being shorted, but now that it's working and I can have some fun with it I don't really feel like pulling the motherboard and tracing the issue out.