Well, it is definitely a cache problem.
I have been able to set it up with a working DOS hard drive and dos tools.
The dos tools report that the external cache is non-existent.
I only have 16kb of cache by default.

I checked the traces and found one trace solder weld to be connecting two jumpers as it was over soldered
And linked two separate jumpers which should not be linked.
So I will fix tomorrow.

Other than that the motherboard works fine with external cache disabled.

So I have everything working now but the external cache.
I can enter bios okay and posts okay.
But posts menu reads that no cache is installed.
I can boot off a DOS hard drive and run some tools.
“Cachechk” Benchmark tool reads only 16kb is installed.
I think this is what the computer defaults to when no cache is found.

I ran other benchmark tools an the computer is running fine and stable.
CPU and jumpers are setup correctly.

The only problem I have now is that the external cache is not being detected by the bios.
I have external cache enabled in bios.

So I am going to try to remove half the cache chips and see if it will work with only 4 cache chips.
The manual reads that it should work.

I have tried everything I can think of and I still can’t get this computer to enable external cache.
It just hangs at the post screen right before booting from hard-drive.
If I disable external cache the computer works fine.

I replaced all the cache chips with new ones.

I think something is wrong with this motherboard.
If I try to disable features like “power management” or change from write-back or write-through.
It just boots into a black screen.

What do you think ?

Are your cache jumpers set properly and working?
Did you try a cache setup with just one bank (128K)?

Yes, I tried everything.
The only thing I can think of is maybe I have the wrong TAG chip.

Here is what I need.
Where can I find this TAG chip ?

How do you know it is wrong? Did you install it yourself?

You should be able to use a bigger chip as soon as it fits in the socket.

Intel486dx33 wrote on 2020-01-13, 22:00:

Yes, I tried everything. The only thing I can think of is maybe I have the wrong TAG chip. […]
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Yes, I tried everything.
The only thing I can think of is maybe I have the wrong TAG chip.

Here is what I need.
Where can I find this TAG chip ?

Using the same type of 32kx8 SRAM (for data AND tag ram) should be fine.
But actually there are some mainboards, that have a jumper for example when a Aster Tag Ram is used, so there must be differences.
But for sure it does not matter if you use a 16kx8 or a 32kx8 size (both are 28 pin) for the tag ram.

Therefore I already asked, which exact sram chip (the tag ram) did you remove?
Was it the same chip type as the data sram?

Intel486dx33 wrote on 2020-01-13, 22:00:

Yes, I tried everything. The only thing I can think of is maybe I have the wrong TAG chip. […]
Show full quote

Yes, I tried everything.
The only thing I can think of is maybe I have the wrong TAG chip.

Here is what I need.
Where can I find this TAG chip ?

Hi,

I had the same issue with some boards and it usually bad cache chips.
If the TAG RAM is faulty that will be reported during post or it will hang there.

Most likely that short you have mentioned destroyed one ore more of your cache chip.

You cannot easily identify the faulty cache chip or chips. To report a bad cache chip during post that chip it needs to be first in the row otherwise the motherboard reads the address from the first chip and considers that all the others are good and then POSTS to the screen you mentioned and there it will hang because it will need to fill the memory address in the chips.

I suggest that you go again inspecting the mainboard!
Do a thorough check on the traces for the cache sockets both visually and for continuity.
You will see that the cache sockets have a lot of common pins. The Input/Output connection are not linked. That is ok!
Also check the chips for shorts. A theoretical working chip will not have any pin shorted with another.
Install the chips and check the temperature on the chips. During normal working condition the chip might be warm to the touch but if it is too hot means that the chip is faulty, or the voltages are wrong.

After you have checked and everything looks fine, with the chips you already have installed start swapping them into sockets. All chips should go through the first socket (I cannot tell you which is the first one). If it is bad it will be reported during post as bad or missing cache.
The bad chip replaces it with another one from your old stash and repeat until you have gone through all chips.

Hope this helps!
If you need further assistance let me know. I have also a list of correct voltages for 32 Pin Cache socket.