Ok so I managed to confirm the fact that the crystal (Y1) is an 8MHz part using pictures off the internet. The resistor (R28) was easy since it's still there, but I can't find any clear pictures to identify the tantalum capacitor (C45)... can anyone help with that?

Manufacturers usually try to keep their Bill of Materials as short as possible. If you look around the board and find that most tantaum capacitors are the same value, odds are the missing one is too.

Where do the crystal traces go to? If it is 8 MHz, I suspect it is for the keyboard controller. (Crystals of that size can also be the 32768Hz crystal for the real-time clock, but it seems there is another small crystal near the chipset which might be the RTC clock).

It really looks like something is hit there, but make sure you know what has fallen off and what was not there in the first place.

The resistor R28 is broken, but if it is connected between crystal pins, I highly doubt it is a 5k resistor. To me it looks like red-black-green-gold which means 2 Mega-ohms, and crystals pins often have something around 1 mega-ohm between them. Including 2 mega-ohms.

From the pictures, I can't really see the soldering on crystal Y1 pins. But it might have been there and now missing.

But be really really careful about capacitor C45. To me, it looks like it is connected to the crystal Y1 pin. The solder pads do not look like something was soldered there and broken off. And even if there were something soldered there, it is most definitely not a tantalum capacitor. Usually, if there is a capacitor, it is a ceramic capacitor, somewhere between 10 and 47 picofarads, so it will look somewhat different to the other standard power pin bypass capacitors that might be tantalum or ceramic. (In short, the crystal will oscillate at a frequency it is rated at, only when the crystal is connected to a capacitive load it is rated at, so wrong capacitance means the frequency is a bit off or it won't oscillate at all).

I hope this helps. Similar era motherboards could be the best part donors.

The parts I mentioned are definitely missing. The crystal's legs are still soldered to the MB, only the crystal itself is missing, same for the capacitor (part of one leg is still soldered). Also just by googling pictures of the motherboard I can see that the aforementioned parts are supposed to be there.

Judging by the shape and markings on the other capacitors, I drew the conclusion that they are tantalum, not ceramic - but as far as I know from the little experience I have with electronics, both a tantalum or ceramic cap will work provided they are the correct capacitance.

You are correct about the resistor - it's gold not brown...

I don't know about the crystal, I can't trace where it leads to... like you said, it's either for the RTC or KB controller, but the latter is most likely.

Here is a picture of a green PCB Morse 386C - the components I mentioned are visible but the picture's size is too small to read values off them:

Thanks for describing the picture, I can now read the picture better and see one quite short leg of the capacitor (the crystal legs are huge in comparison).

But for a certain job, there is a certain capacitor type (or a few..), and crystal circuits commonly use ceramic caps, because they are the best for that job.
One reason why it is not tantalum is that the smallest value tantalums that are commonly available (today) are 3 or 4 decades (1000x-10000x) larger in value than what is applicable to crystal circuits. Anyway, it might work without a capacitor so try it first without a capacitor. Even better if you have access to an oscilloscope (use 10x probes as crystal circuits are very sensitive) to verify it is working or if the speed is correct.

I tried to scan the whole motherboard picture for the RTC crystal, and I can't find one. There's the 14.318 MHz crystal for the ISA bus and timers, then there are the two oscillators (40 and 50 MHz). I can't find a RTC chip either so it must be integrated into the chipset chips. I am not so sure if the missing crystal is for the KB controller any more (it could get its clock from the other sources), so the missing part could be the 32768Hz RTC crystal. Usually RTC crystals are small cylinders while faster frequency crystals are not, and usually RTC crystal circuits use 2 Mohm or even larger bias resistors than faster frequency crystals that are around 1 Mohm.

Well if you get it booting and the time does not advance, then it is the RTC crystal. If it boots and you can't use the keyboard, then its the KBC crystal.

I see, that would should do it indeed. Unfortunately I don't own an oscilloscope, so probing the crystal is out of the question... I'll have to take a trial and error approach.

In any case, it's almost 23:00 here so I can't set up my test bench and see if whether the KB or RTC don't work, but I'll do it tomorrow first chance I get. I can get a small cylindrical RTC crystal off a dead P5MVP3 or a KB crystal off a dead 486 board, so that will help. I can't find the appropriate resistor on any of my dead boards - I'll have to purchase a new one, but I have loads of ceramic caps.

I'll update the thread tomorrow.

The other picture is from http://cpumuseum.jimdo.com/museum/others/cpus-on-board/ - might be worth asking if he has the board or just the picture

I started it again and it posted after swapping the RAM!

I got 8x1MB of 30 pin simm memory off an old 33MHz 486 as well as a 1GB SCSI toshiba HDD (it's a biggie - double thickness 3.5" 😁). I'm also using my Tseng ET4000 ISA video card and an ADAPTEC AHA-1542C ISA SCSI controller on it. Keyboard works fine. RTC seems to count down in bios so I assumed it works, but it doesn't really. The MB does save CMOS settings (would you belive the batt still works? Tested at 3.1v and it's not leaking 😁 ) but not the time. It does count up tough.

The HDD has Win95 pre installed so I booted that in command prompt only and ran Prince of Persia on it (it was on the drive).

I'm currently running speedsys on it - CPU is read at 13MHz not 25MHz, alltrought the CPU, FPU and motherboard all read 25MHz and they scored 1,64 points.

I'm SO EXCITED it's the first time I used a 386 computer! I've never used anything slower then a 486-66 in my life! 😁

Does anyone have a 386 motherboard with a cylindrical crystal near the keyboard controller? Can you tell me the value written on it?

Hello, I have a motherboard like this Morse KP-386C but I think it is in short because the power supply not switches on.
If I connect the P9, the power supply switches on but if i connect even the p8 the fun of the power supply wont turn on.

The powergood doesn't come back?
May be a problem on the 12volt line?
What should I test or replace?
Thanks in advance.

May these tantalum caps?