run cachechk v7 under dos with no thing else running. no autoexec, or config.sys speedsys is also helpful, because it will generate a picture we all can look at.

Here is SpeedSys report:

And here is Cachechk v7 report:

CACHECHK V7 11/23/98 Copyright (c) 1995-98 by Ray Van Tassle. (-h for help)
CMOS reports: conv_mem= 640K, ext_mem= 7,168K, Total RAM= 7,808K
386 Clocked at 39.0 MHz
Reading from memory.
MegaByte#: --------- Memory Access Block sizes (KB)-----
1 2 4 8 16 32 64 128 256 512 1024 2048 4096 <-- KB
0: 64 63 63 63 63 63 63 63 63 63 -- -- -- us/KB
1: 64 63 63 63 63 63 63 63 63 63 63 63 63 us/KB
2 3 <--- same as above.
4: 63 63 63 63 63 63 63 63 63 63 63 63 63 us/KB
5 6 7 <--- same as above.

Extra tests----
Wrt 35 35 35 35 35 35 35 35 35 35 35 35 35<-Writing
This machine does not seem to have any cache.
Hmmm. It looks like megabyte #1 isn't being cached!
Hmmm. It looks like megabyte #2 isn't being cached!
Hmmm. It looks like megabyte #3 isn't being cached!
Hmmm. It looks like megabyte #4 isn't being cached!
Hmmm. It looks like megabyte #5 isn't being cached!
Hmmm. It looks like megabyte #6 isn't being cached!
Hmmm. It looks like megabyte #7 isn't being cached!
Hmmm. It looks like RAM at megabyte #1 is REALLY slow!
Hmmm. It looks like RAM at megabyte #2 is REALLY slow!
Hmmm. It looks like RAM at megabyte #3 is REALLY slow!
Hmmm. It looks like RAM at megabyte #4 is REALLY slow!
Hmmm. It looks like RAM at megabyte #5 is REALLY slow!
Hmmm. It looks like RAM at megabyte #6 is REALLY slow!
Hmmm. It looks like RAM at megabyte #7 is REALLY slow!
Main memory speed -- 17.4 MB/s 60.1 ns/byte (100%) [reading] 9.0 clks
Effective RAM access time (read ) is 120ns (a RAM bank is 2 bytes wide).
Effective RAM access time (write) is 67ns (a RAM bank is 2 bytes wide).
386 Clocked at 39.0 MHz. Cache ENABLED.
Options: -t0

The cache is definitely off. I would double check your motherboard jumpers. Triple check the resistor packs that are removable. One might be broken.

Jumpers have been checked twice. Checked both of resistor packs and they are ok. You know it's a little bit strange that self-testing doesn't respond to incorrect installed/configured chips or to some circuit disruption.

This might help:http://museum.ttrk.ee/th99/m/M-O/33296.htm
Do you have different cache modules to try? If you were close to my city, I would give you a set of them, I have more then I need anyway.

btw, why is there TEN dip sockets? Why not 5 or 9?

usually with 10 sockets, the tag ram is supposed to be 64kx1 bit rams, or sometimes its for a "dirty bit"

either way, its not as easy ans the "normal" 9 socket L2 cache.

RacoonRider
Already tried with modules which have been borrowed from PVI-486SP3 but with no luck.

luckybob
Indeed. M10 module is for "dirty bit" and is optional.

Tried to install 80486DX2 - still no cache.

Return all settings to 386 setup with no changes, but today I tried to check it with "new" CyrixDX2v66 and you know what... mb didn't start at all. Of course the first think was that CPU had a malfunction so I tried DX2/66 Overdrive which was in last working setup. No success. Both CPU's were checked after that and are non-fault. After getting 386 jumper setup back mb is starting as before (w/o cache).

I'll postpone the mobo and maybe after xx years it'll be the only surviver.

Thanks all for concern.

Now tried with just arrived 20ns cache chips (before that there were 15ns SRAM chips) and you know what? Cache works now! 😁

Can't find 33MHz oscillator but hope the motherboard will start with new one. The old one had been checked with oscilloscope and there is no frequency.

stbunny wrote:

Now tried with just arrived 20ns cache chips (before that there were 15ns SRAM chips) and you know what? Cache works now! 😁

Can't find 33MHz oscillator but hope the motherboard will start with new one. The old one had been checked with oscilloscope and there is no frequency.

I would assume that one of the old chips is bad.

luckybob wrote:

I would assume that one of the old chips is bad.

So I'll try to locate bad chip(s). One thing I can't understand - I replaced these SRAM-chips with working 15ns ASUS PVI-486SP3 cache chips with no luck.

All of old chips are faulty! How could it be?
Trying to find a datasheet for them and can't get any.

Here is picture:

Looks like a real SRAM chip... and behaves like a fake.