VOGONS


Need help identifying 8088 motherboard

Topic actions

First post, by sqeeek

User metadata
Rank Newbie
Rank
Newbie

Hello!

I've got an ADDS PC-I that won't post. Two beeps, then repeated 1 long 3 short. It had an expansion card with RTC/RAM/Serial on it that someone added, my best guess so far is that they were trying to set it up for the extra RAM and messed up the DIP switches.

There are no jumpers, just two sets of DIP switches, SW1 and SW3. SW2 is on the keyboard controller's daughter board rather than on the motherboard itself.

The motherboard says it's a Multitech MPF-V PB8307010, I can't find any info anywhere, even on arvutimuuseum.ee.

Here it is:
ylgA9kQ.jpg
https://i.imgur.com/ylgA9kQ.jpg
https://i.imgur.com/ySItrB6.jpg
https://i.imgur.com/YDZDV2V.jpg
https://i.imgur.com/piwvDir.jpg

Any guesses? Any advice would be appreciated.

Reply 1 of 22, by bakemono

User metadata
Rank Oldbie
Rank
Oldbie

It seems that Multitech was the predecessor of Acer, and their first few MPF models were Apple clones. MPF-V is briefly mentioned here:
https://archive.org/stream/nzbitsandbytes-2-0 … e-2-08_djvu.txt

MPF-V is an IBM compatible. 16-bit […]
Show full quote

MPF-V is an IBM compatible. 16-bit

8088 machine with 128K bytes,
expandable to 256K. It has colour
graphic capability and full tilt and
swivel display monitor.

Taking a wild guess, since the 8255 is on the daughter card, maybe the switch block located nearby has similar function to an XT. And SW3 being next to the DRAM chips pertains to memory config? Sorry, that's all I've got.

GBAJAM 2024 submission on itch: https://90soft90.itch.io/wreckage

Reply 2 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie
bakemono wrote:
It seems that Multitech was the predecessor of Acer, and their first few MPF models were Apple clones. MPF-V is briefly mentione […]
Show full quote

It seems that Multitech was the predecessor of Acer, and their first few MPF models were Apple clones. MPF-V is briefly mentioned here:
https://archive.org/stream/nzbitsandbytes-2-0 … e-2-08_djvu.txt

MPF-V is an IBM compatible. 16-bit […]
Show full quote

MPF-V is an IBM compatible. 16-bit

8088 machine with 128K bytes,
expandable to 256K. It has colour
graphic capability and full tilt and
swivel display monitor.

Taking a wild guess, since the 8255 is on the daughter card, maybe the switch block located nearby has similar function to an XT. And SW3 being next to the DRAM chips pertains to memory config? Sorry, that's all I've got.

That's helpful, thanks!

Reply 3 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie

Looking at some beep charts again, it's looking like I might have a RAM problem. I'll start looking up chip numbers, I know I have enough to replace the RAM istelf but when it comes to the controller I'm pretty new to the 8088 world so I'll have to do some homework.

Reply 4 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie

I spent another couple of hours on it over the weekend. So far, I've tried:
1. Searching extensively for any information based on the BIOS stickers, board/chip numbers, etc
2. Many DIP switch combinations
3. Testing a few capacitors
4. Replacing the RAM, but cutting it down to one bank instead of all 4
5. Multiple video cards

This one is kicking my butt. I'm not really sure where to go next. Buy an EEPROM reader? Start testing every board component? For some reason, I'm determined to get this to work.

If any of you have any advice on next steps, I'd appreciate it.

Reply 5 of 22, by Predator99

User metadata
Rank l33t
Rank
l33t

Indeed, without documentation you will not find out what the beep codes mean.
Does it change when all RAM is removed?

Yes, I would suggest to buy a EPROM reader and try a diagnostic ROM.

Reply 6 of 22, by Caluser2000

User metadata
Rank l33t
Rank
l33t

Dip settings on old IBMs any help? http://minuszerodegrees.net/

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 7 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie
Predator99 wrote:

Indeed, without documentation you will not find out what the beep codes mean.
Does it change when all RAM is removed?

Yes, I would suggest to buy a EPROM reader and try a diagnostic ROM.

No change until I get down to the first bank. If I remove anything in the first bank, it'll beep twice and then halt, rather than beeping twice and then "1 long 3 short" repeatedly.

I'll see if I can get my hands on an EPROM programmer. Have you used those ISA POST code boards? I've seen a few floating around, not sure if that would shed any light but I figured it might be worth the $7 or whatever to give it a shot.

Reply 8 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie
Caluser2000 wrote:

Dip settings on old IBMs any help? http://minuszerodegrees.net/

I've tried everything I could find there and didn't see any change. Thank you though.

Reply 9 of 22, by Predator99

User metadata
Rank l33t
Rank
l33t
sqeeek wrote:
Predator99 wrote:

Indeed, without documentation you will not find out what the beep codes mean.
Does it change when all RAM is removed?

Yes, I would suggest to buy a EPROM reader and try a diagnostic ROM.

No change until I get down to the first bank. If I remove anything in the first bank, it'll beep twice and then halt, rather than beeping twice and then "1 long 3 short" repeatedly.

I'll see if I can get my hands on an EPROM programmer. Have you used those ISA POST code boards? I've seen a few floating around, not sure if that would shed any light but I figured it might be worth the $7 or whatever to give it a shot.

RAM seems to be OK then. Did you try several graphics cards?

On a XT you will only see weird numbers on the POST card, thats of no use. But in general good investment, order one from China.

Buy a TL866 programmer, think most here are using it.

Reply 10 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie
Predator99 wrote:
RAM seems to be OK then. Did you try several graphics cards? […]
Show full quote
sqeeek wrote:
Predator99 wrote:

Indeed, without documentation you will not find out what the beep codes mean.
Does it change when all RAM is removed?

Yes, I would suggest to buy a EPROM reader and try a diagnostic ROM.

No change until I get down to the first bank. If I remove anything in the first bank, it'll beep twice and then halt, rather than beeping twice and then "1 long 3 short" repeatedly.

I'll see if I can get my hands on an EPROM programmer. Have you used those ISA POST code boards? I've seen a few floating around, not sure if that would shed any light but I figured it might be worth the $7 or whatever to give it a shot.

RAM seems to be OK then. Did you try several graphics cards?

On a XT you will only see weird numbers on the POST card, thats of no use. But in general good investment, order one from China.

Buy a TL866 programmer, think most here are using it.

I tried two graphics cards. I guess it would be smart to try them in a new computer, it's definitely possible they're dead.

Oh, good to know, I didn't realize the XT was before the BIOS started broadcasting them on whatever that ISA channel was. I'll grab one though, sounds very useful.

Nice, that makes me feel better. I was just looking at them on eBay - I found a TL866A, I hear the newer ones are limited to 18v so I figured I'd grab one of those instead.

Reply 11 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie

I threw the ISA graphics cards I had into a working machine, a little bit newer, Cyrix 486 clone with PCI slots as well. The VGA card worked, the monochrome RCA card did not. I'm trying to find some jumper settings on the card to set it to monochrome, maybe that would help.

Reply 12 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie

WELL now I feel extremely dumb. It appears that what I have may be a Willow Peripherals Video Publisher card, an 8 bit RCA capture card. That would be why it's not working.

Now to see if I can figure out what settings I need on the other card. Good grief. How much do you want to bet it just needs a video card in it?

Reply 13 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie

So here's the card I have: http://arvutimuuseum.ee/th99/v/U-Z/52859.htm

I've got it working in another machine, but I'm not sure I have the settings right on the 8088. Does this look like it might work in an XT clone?

Reply 14 of 22, by Predator99

User metadata
Rank l33t
Rank
l33t

Yes should work in the XT with same settings as in the 486. But the XT-Board needs to be set to Color graphics, not MDA. Are the beep codes different without the card installed?

Reply 15 of 22, by Caluser2000

User metadata
Rank l33t
Rank
l33t

Yeah the card should work fine jumpered as mentioned above.

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 16 of 22, by Scali

User metadata
Rank l33t
Rank
l33t

Note that on an XT there are dipswitches to select the video... CGA, MDA or other. This is because the CGA and MDA BIOS code are included in the motherboard. When using VGA, this needs to be bypassed, and the BIOS on the VGA card can do its work.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 17 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie
Scali wrote:

Note that on an XT there are dipswitches to select the video... CGA, MDA or other. This is because the CGA and MDA BIOS code are included in the motherboard. When using VGA, this needs to be bypassed, and the BIOS on the VGA card can do its work.

I may have finally found some settings that match! I'll keep you posted. Thanks for the help everyone.
https://www.vintagesbc.it/?page_id=151

Reply 18 of 22, by sqeeek

User metadata
Rank Newbie
Rank
Newbie

IT WORKS
I'M LOSING MY @#$% I'm so excited.

Changed SW2 (on keyboard daughter board) to on/on and it displayed some text. "Error, press F1 to continue". That's a great sign! Officially in business. Thank you guys a ton for your help.

Reply 19 of 22, by Caluser2000

User metadata
Rank l33t
Rank
l33t

Awesome well done.

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉