I don't see how the missing pin on the FPU could possibly cause any damage to the board. Are you sure you didn't insert it in the wrong direction?

Anonymous Coward wrote:

I don't see how the missing pin on the FPU could possibly cause any damage to the board. Are you sure you didn't insert it in the wrong direction?

Only if the orientation mark on the chip is wrong... I always align the cut-off corner with FPU cut-off corner or the dot if it has this instead.

I'm wondering if I can bypass the "wait....", whilst I look to find a spare of that IC.

Anonymous Coward wrote:

I don't see how the missing pin on the FPU could possibly cause any damage to the board. Are you sure you didn't insert it in the wrong direction?

Definitely the right direction...

Did you wait a while at 'WAIT'? Did you try to clear the CMOS?

Remove all the cards except VGA and also disable all the IDE and floppys in BIOS and memory cache.

You should wait till some error pops up - around a minute.

That IC is a 74244 buffer, should be easy to find if you do decide to replace it. 74 logic is very common, has been around for years and probably isn't going away any time soon.

For example; http://www.ebay.co.uk/itm/IC-BUFF-DVR-TRI-ST- … aIAAOxy4YdTPxiu

Should give you an idea what you are looking for. Though I'm not sure how a missing pin would break something permanently, I suppose it isn't outside of the realms of possibility. If something was allowed to float high who knows what might have happened and to figure it out would be a long winded exercise requiring intimate knowledge of the internal workings of the chips - I guess maybe some freak occurrence could let the diode protection leak a certain way or something...

Whatever, kixs has the right idea here. Some BIOS has upwards of a 2 minute wait time, so just set the machine off going and go do something else for a while, it will either have failed to boot (implying it can't find a problem) or else will have thrown up an error message by the time you return. At least, assuming all goes to plan.

Thanks for all the tips and pointers.

Yea, I removed all cards except VGA, cleared the CMOS... and waited, and waited. I left the screen like this for up to 10-20 mins at a time still to no avail. One time I did get a message though whilst pressing F1 but it only happened the once and was something to do with "memory size error".

I'm just thinking now that maybe the bios may be corrupt and to maybe pull from another board and try a new 386 AMI bios? If in the rare chance someone recognizes this particular bios let me please know as I could request a copy of it.

Really strange how a co-pro with a missing pin can cause so much trouble.

Ok... time for an update.

Since the last post I have; -

1) Tried a new Bios ROM
2) New buffering IC
3) and a new 386 CPU

All 3 of these replacements make no change and the board still hangs at "Wait..." 🙁

But... when I clear the CMOS, it will go passed the waiting to give a message "CMOS battery low" and looks for (f1) to be pressed (to enter the bios). Once I save changes and exit... it hangs at "Wait...) again!

I'm getting stumped on this and fresh ideas would be appreciated.

The only other thing I can think to do is to find where the missing pin would be on the socket and follow the trace to see where it goes... hopefully leading to where the problem may be (if it is a hardware issue).

I wonder what that missing pin may have been for, I hope that you get it working so that people in the future can have something to reference if they get this problem. Have you tried replacing them ram by chance? I amazed how often the ram acts up on the boards with all kinds of strange out of the blue issues.

maybe the CMOS SRam has a defect ?

What was the replacement buffer type? The original was 74F so chances are other types can be too slow or too fast or otherwise electrically noncompatible.

I agree with Jepael, a 74F ic must be replaced with a 74F, but I doubt that's the problem here anyway.
There is some information lacking here that could help though.

1. A photo of the chip with the missing pin clearly displayed
2. The Brand and model of Motherboard, or full layout photo will suffice

You haven't possibly changed any jumpers as far as FPU configuration is concerned?

Brilliant... the board is now fully POST'ing!

I'd have to say... there is a mixture here of human error at play here 😁 / and lack of information about this board online (i.e. no jumpers avail).

From my part... I've always had an FPU installed on this board since I got it, and since then I've never been able to find jumper config info online anywhere. So when recently I decided to test a bunch of FPU's I'd bought... it was the first time I'd run it without an FPU and getting to this endless "Wait..." state. The one time I did try an FPU back in the socket... I of course had the damn thing software disabled in the bios! 😊

In fairness, I had been toggling the FPU on/off using the option in the bios to troubleshoot (with no FPU installed!)... and did try all the jumpers I could see in the vicinity just in case, to no avail... so to me it looked as if I had covered all FPU configuration options... until last night!

There is a sneaky solitary jumper that eluded me all the way over on the other side of the board by the RAM banks... how / why this is on the the other side of the board I do not know, but I had already removed & inserted jumpers into everything and anything around the bios, FPU & CPU socket which did squat! This one, did the job.

I am extremely happy now to have it working again, and that there are no internal shorts anywhere... (that would not be fantastic).

Thanks to everyone for your help... it is much appreciated.

Good news!

Can You still post a photo of the whole board? You never know, someone here may find some technical information somewhere out there.

Imperious wrote:

Good news!

Can You still post a photo of the whole board? You never know, someone here may find some technical information somewhere out there.

I managed to find a decent stock photo courtesy of Amoretro; -

I have searched far and wide... but there is little to no information on this board anywhere.

I think this might be it, definitely the closest I can find anyway.

http://www.arvutimuuseum.ee/th99/m/P-R/32794.htm

Imperious wrote:

I think this might be it, definitely the closest I can find anyway.

http://www.arvutimuuseum.ee/th99/m/P-R/32794.htm

That's great! Thanks for posting... I think it pretty much is the same board.

I had only the siikscreen to go by as search parameters... though they served more as a decoy.

A working board and now jumper config... brilliant! 😁

Thanks again

Unfortunately the page is still missing the W6 jumper function at the bottom, below the FPU. My best guess is that it toggles between socketed CPU and PQFP soldered CPU.