Can't really help with the jumpers but I do have questions:
- Is that an 80287-10 next to 20MHz 286? This actually works?
- There seems to be 1MiB of DRAM in sockets?

I don't see parity chips for the on-mobo DRAM so it's a good candidate for those "new" 4MiB SIMM sticks? But then again it would need two, and 286 with 8MiB (well, 9 in total) seems like a waste.

Deunan wrote on 2022-02-08, 14:53:

Can't really help with the jumpers but I do have questions: - Is that an 80287-10 next to 20MHz 286? This actually works? - Ther […]
Show full quote

Can't really help with the jumpers but I do have questions:
- Is that an 80287-10 next to 20MHz 286? This actually works?
- There seems to be 1MiB of DRAM in sockets?

I don't see parity chips for the on-mobo DRAM so it's a good candidate for those "new" 4MiB SIMM sticks? But then again it would need two, and 286 with 8MiB (well, 9 in total) seems like a waste.

I haven't gotten the board yet, but here are two more pictures with closeup views of the ram and 80287. The pictures are from the seller I am getting the motherboard from.

Most of the jumpers look labeled and are the front panel connectors .
JP9 and 12 look to be Turbo Switch and Turbo LED
JP10 Mono or Colour graphics
JP13 Reset
JP11 Speaker
JP14 (?) Power LED and Keylock.

JP4 by the PSU connector looks like an external (pin 1&4)/internal (pin 1&2) battery selector, and at a guess it'll also work as a clear CMOS jumper by moving the jumper to either 1&2 or 3&4 (whichever of pin 1 and 4 is the ground, I think pin 2 is the battery +ve pin, so clear CMOS might be 3&4).
JP2&3 might be to select which RAM banks are active.

Can't just see where JP1 is and JP5,6,7,8 aren't fitted. Maybe they're something to do with enabling/disabling the co-processor.

[edit: oh, there it is, over by the barrel 'o doom battery, hard wired as 2-3. No idea about that one.
Oh, and on the battery, top of board looks fine, but there's what looks like some minor damage to a trace on the bottom, so you may want to remove the battery and give that area a clean.]

Deunan wrote on 2022-02-08, 14:53:

Can't really help with the jumpers but I do have questions: - Is that an 80287-10 next to 20MHz 286? This actually works? - Ther […]
Show full quote

Can't really help with the jumpers but I do have questions:
- Is that an 80287-10 next to 20MHz 286? This actually works?
- There seems to be 1MiB of DRAM in sockets?

I don't see parity chips for the on-mobo DRAM so it's a good candidate for those "new" 4MiB SIMM sticks? But then again it would need two, and 286 with 8MiB (well, 9 in total) seems like a waste.

Some 286 chipsets have divided clock outputs for the KBC etc. that are used for the NPU as well

maxtherabbit wrote on 2022-02-08, 15:55:

Deunan wrote on 2022-02-08, 14:53:

Can't really help with the jumpers but I do have questions: - Is that an 80287-10 next to 20MHz 286? This actually works? - Ther […]
Show full quote

Can't really help with the jumpers but I do have questions:
- Is that an 80287-10 next to 20MHz 286? This actually works?
- There seems to be 1MiB of DRAM in sockets?

I don't see parity chips for the on-mobo DRAM so it's a good candidate for those "new" 4MiB SIMM sticks? But then again it would need two, and 286 with 8MiB (well, 9 in total) seems like a waste.

Some 286 chipsets have divided clock outputs for the KBC etc. that are used for the NPU as well

I will be out swapping out the 80287-10 for a 80287XL that I have put aside.

Looks like JP5 had something soldered to it at one point, so if you do take the existing NPU out then it might be worth trying to trace what JP5-8 connect to.

I'm setting up this board right now. Haven't figured out the jumpers yet, but they do affect the amount of RAM the system sees when SIPP modules are installed (got 5 megs recognised only when the jumpers are set like in your picture, otherwise it's 640K or around 2.5 megs). So two theories so far is that they either affect memory banks 0-3, or change waitstates (RAM from 0 to 1, ROM from 2 to 3).

I'll benchmark the system with various jumper settings to test the waitstates theory. However, this board with the same chipset does have two jumpers to switch between RAM configurations. https://theretroweb.com/motherboards/s/biosta … r.-01#downloads

Have you been able to find the EMS driver for this chipset? I've been looking everywhere without success 🙁

jheronimus wrote on 2022-11-25, 04:41:

I'm setting up this board right now. Haven't figured out the jumpers yet, but they do affect the amount of RAM the system sees when SIPP modules are installed (got 5 megs recognised only when the jumpers are set like in your picture, otherwise it's 640K or around 2.5 megs). So two theories so far is that they either affect memory banks 0-3, or change waitstates (RAM from 0 to 1, ROM from 2 to 3).

I'll benchmark the system with various jumper settings to test the waitstates theory. However, this board with the same chipset does have two jumpers to switch between RAM configurations. https://theretroweb.com/motherboards/s/biosta … r.-01#downloads

Have you been able to find the EMS driver for this chipset? I've been looking everywhere without success 🙁

The PC Chips M218 uses the VLSI VL82C311L "SCAMP" chipset. I have been able to get a full 16MB of ram working by changing the JP2 & JP3 jumpers which control the ram banks used. As to an EMS driver, I found one but have not had any real success getting it to work. I am uploading a copy in the hope you can figure out how to get it working. Here is a post on the DOS Days website which mentions the PC Chips M218 motherboard and some performance info:

https://www.dosdays.co.uk/topics/get_a_286_ru … e_a_386_pt1.php

Thanks for the image! At least now I know the filename, finally 😀

Doesn't seem to work for me either. Tried all window options, tried unshadowing all addresses in the BIOS just to make sure and also enable/disable EMS Global control — still says "EMS Disabled" at boot.

With the full respect to the dosdays author, the linked page is incomplete and misleading in many places.
Still, an enjoyable read.

jheronimus wrote on 2022-11-25, 06:08:

Thanks for the image! At least now I know the filename, finally 😀

Doesn't seem to work for me either. Tried all window options, tried unshadowing all addresses in the BIOS just to make sure and also enable/disable EMS Global control — still says "EMS Disabled" at boot.

You ran into the same thing I did. The EMS driver does not work. My alternative was to use UMB_DRVR and UMB_EMS package v5.22. This gives me upper memory and although the EMS driver is a software solution, it works quite well for me with DOS applications. I am attaching a copy.

I used to have 286 in 1991 but never had any need for EMS - at least that's my memory. What programs/games require EMS on a 286?

kixs wrote on 2022-11-25, 19:31:

I used to have 286 in 1991 but never had any need for EMS - at least that's my memory. What programs/games require EMS on a 286?

My main use for EMS on a 286 is for development tools and programs like Lotus 123. As far as games go, I think some of the Commander Keen series and Wolfenstein 3D can make use of EMS memory.

kixs wrote on 2022-11-25, 19:31:

I used to have 286 in 1991 but never had any need for EMS - at least that's my memory. What programs/games require EMS on a 286?

I think there are a few games that use EMS for extra features/effects — Wing Commander, X-Wing, for example.