https://www.youtube.com/watch?v=iHcJDzbZPng

The Turbo button on my XT also doesn't seem to do anything. That is, until you reset the computer.
Seems like the chipset only checks the state of the turbo button on startup.
The bios has the ability to switch speed using a key combo, though the moment you load a keyboard driver that functionality is lost.

Maybe your 286 is similar ?

weedeewee I found a fix for it but I dont know if your XT has the same bios settings as mine I looked at the video Nexxen posted above and I forgot about the CTRL+ALT+"+" and "-" I was able to get it sort of working but that meant I had to use the keyboard first then it was ok for me to use the turbo button every time at boot, but the fix is if you have it in your bios is to turn "power up speed" from fast to normal, below is a video of my 286 but the first 5 seconds is just a black screen but after that its ok but ide like to see if there is a way to use "fast" instead of "normal"

https://drive.google.com/file/d/1GAsQLRncm2d- … iew?usp=sharing

GabrielKnight123 wrote on 2022-10-07, 15:05:

weedeewee I found a fix for it but I dont know if your XT has the same bios settings as mine I looked at the video Nexxen posted above and I forgot about the CTRL+ALT+"+" and "-" I was able to get it sort of working but that meant I had to use the keyboard first then it was ok for me to use the turbo button every time at boot, but the fix is if you have it in your bios is to turn "power up speed" from fast to normal, below is a video of my 286 but the first 5 seconds is just a black screen but after that its ok but ide like to see if there is a way to use "fast" instead of "normal"

https://drive.google.com/file/d/1GAsQLRncm2d- … iew?usp=sharing

my XT has no bios settings aside from the dipswitches on the board. the key combo just writes to a specific register to switch between high & low speed.
The turbo button behaviour is also described in the datasheet of the chipset... ali m1101 ? which is a relabeled umc chip.
I do not have an issue with it. It's documented behaviour, known and expected.

Ok weedeewee but is there a way to fix my 286 so I can get it to run as "fast" in the bios what about a bios update but I dont have a flasher so if there is a dos program instead that would be better for me

GabrielKnight123 wrote on 2022-10-07, 16:48:

Ok weedeewee but is there a way to fix my 286 so I can get it to run as "fast" in the bios what about a bios update but I dont have a flasher so if there is a dos program instead that would be better for me

I guess there's a slight lost in translation going on, but no worries.

my XT starts in hi or lo mode, dependent on how the turbo switch is set on bootup.
while started, the turbo button does nothing, until a reset or powerdown/powerup.
I was contemplating that your 286 might have similar behaviour.

as for the switch you are using...
Is it a latching switch, not a momentary like a reset button
Are the wires still properly connected
Can you measure if it is still properly switching on/off
?

OK, just watched your video, and yeah the bios is somehow being a nuisance for you.

There's plenty of boards out there with the HT12 chipset out there. I have two or three that look very similar to yours.
https://theretroweb.com/motherboards/s/tidalp … i-025c-ht12-286
That seems to be yours, and the available bios is an AMI one according to the download listing.
If you have a programmer, save your bios and upload it to the ...frigging thread that eludes me at the moment. then try that AMI one that's for download on theretroweb site.

I found the exact same board as in my picture amongst my hoard with everything the same like chipset and CPU etc. so I thought maybe this one would be ok but I'm getting the same turbo button problem in my video so could this be on purpose for some strange reason or is this motherboard just some sort of el cheapo bottom of the barrel that was sold at the time back when 286's were sold

AT class machines sometimes have an option to enable or disable turbo function in CMOS setup. Enabling mean the switch and keyboard combos if supported work, disabled meaning they don't. On an XT portable I have, clamshell style, bit of a stretch to call it a laptop, there is a setup function key always available, and that pops up the setup screen where turbo is turned on and off on the fly, in that case, enabled means full design speed (7 or 8Mhz I think) and disable means it runs at IBM PC 4.77Mhz... though some diags claim 4, but not sure if that's seeing the V30 as a 286 and thinking it's a 4mhz AT or what.