# Turbo is not turbo

2026-09-15 (prehistory). I spent weeks calling the PB686's speed control "turbo". There's no turbo switch at all; it's a keyboard shortcut that flips between 8 and 12 MHz.

Source page: https://barelybooting.com/atlas286/journal/2026-09-15-turbo-is-not-turbo/

Another one from before the from-scratch Atlas, while I was still working out what the PB686 actually was. My notes kept calling its speed control "turbo", and when I opened the case on 14 September my plan included checking the turbo jumper or switch. There isn't one. No jumper, no switch.

The next day at the bench I found the keys: Ctrl + Alt + keypad minus. Press them and the machine changes speed right there. At the slow speed its serial console even started dropping characters. What I said at the time: "it seems like a 8MHz and 12Mhz toggle - there's no 'turbo' verbiage". The front panel has two little lights, 8MHZ and 12MHZ, and that's it.

None of my documents had ever mentioned those keys. "Turbo" was my word all along, never the machine's.