Maybe it could be worth looking closely at the small chip near the buzzer?
It is slower than a 286-16 😀

Edit:
Near to the chip and the buzzer are also two connectors, 34 and 40 pin.
So there is only left to make sure that the PSU connector actually is P8/P9 compatible, so that the self-destruct function does not get triggered.

wbahnassi wrote on 2021-10-01, 15:32:

Hi, I'm looking for your help identifying this 286 motherboard I recently found.

Nope, that is a 386 board. You have 16MHz Intel 386SX on it, you even took a photo of it. That socket is for 387SX NPU.

I think this is it https://www.ultimateretro.net/motherboards/1805

Philips P3345 ?

Is that no written on the board? Still not 100& this is the board, as slightly different shape.

Ok a few more pics around the buzzer and the P8/P9 power connector:

I don't see where it says Philips P3345, but looks like Mr.Slug's link is indeed showing the right schematics. I wasn't familiar with this CPU package type before. Nice.

Now, looking at the manual linked in Mr.Slug's link, it doesn't seem to include neither an HDD led connector, nor a Turbo button connector, right? I thought all mobos from this era had a Turbo switch.

BTW, the previous owner said the machine that was using this board was turning on but not showing anything on the screen. I haven't tried it yet, but I hope it was something stupid that was preventing it from working.

DEC was a business orientated manufacture and turbo buttons probably weren't high priority. Sometimes there is a key combination to switch speeds. Shift-ctrl-+ I think, perhaps someone else can remember. Dunno about the HDD light though.

Can we use your image on our site? Ultimate Hardware 19 now has close to 9000 motherboards.

mR_Slug wrote on 2021-10-02, 19:11:

Can we use your image on our site? Ultimate Hardware 19 now has close to 9000 motherboards.

Sure no problem. I can try to take better or detailed pics if needed also.

Hooked it up last night and started to hear sweet music to my ears: beeps and blips 😀
At first I didn't get any picture (just like previous owner said). I hooked it up on a CRT he gave me, which I tested on a different machine and it lit up and gave a beautiful picture. However, on this 386SX it failed to show any picture. It's hooked up to an ATI Wonder 16 VGA card, so I tried a modern LCD monitor and I got picture.. 🤷‍♂️

For the record, to enter the BIOS setup utility on this mobo keep pressing Ctrl+Alt+Insert at different times during the POST screen. POST doesn't show any help messages on how to enter the BIOS, so I thought this might come in handy for any Philips 386SX mobo owners to come.

SDumas wrote on 2021-10-01, 22:30:

Philips P3345 ?

Correct, I own one

mR_Slug wrote on 2021-10-02, 19:11:

DEC was a business orientated manufacture and turbo buttons probably weren't high priority. Sometimes there is a key combination to switch speeds. Shift-ctrl-+ I think, perhaps someone else can remember. Dunno about the HDD light though.

Can we use your image on our site? Ultimate Hardware 19 now has close to 9000 motherboards.

The speed can be changed in the BIOS
The HDD light is directly connected to the HDD

Coming again for this. Anyone knows what "burn in mode" switch is for on this motherboard:

https://stason.org/TULARC/pc/motherboards/D/D … SX-CE-P334.html

Cheers!

usually runs looped self test

Some more digging. Apparently this motherboard was used in the Magnavox Headstart 500

https://wiki.preterhuman.net/Magnavox_HeadStart_500

I found a manual convering several similar Magnavox models, and it revealed a secret key combination to toggle Turbo mode on/off. It beeps on toggle. You press Alt+LeftShift+RightShift.

Manual: https://drive.google.com/file/d/1Xqjl7oJK3_lm … iew?usp=sharing

POST codes can be found here (look for Magnavox Philips):
https://mrbios.com/techsupport/award/postcodes.htm

Funny it is mentioned this motherboard was made in Montreal, which is where I got it from as well 😀

Setup disks:
https://vetusware.com/download/Andy%20Samuels … 01991/?id=10018

I couldn't find exactly what CMOS battery it used. It is visible in the photo above. Anyone has experience what type of battery/voltage it could be? I'm assuming it is not rechargeable...