CoffeeOne wrote on 2024-02-09, 16:49:

rasz_pl wrote on 2024-02-09, 15:28:

by Chkcpu analysis:
>Apart from this extra routine, these BIOSes are identical.
you wont gain anything by flashing official bios

That's what I wanted to say, too. Complete overkill to get a programmer and buy a new chip in this case.
Changing to the official BIOS does not hurt is true, but only if you have everything at hand.

But I will buy some real cache chips. I'm asking for that case.

Chkcpu wrote on 2024-02-08, 19:09:

I agree, the official 2A4X5H03C BIOS should work fine and will indicate the actual L2 cache size. With the fake chips it will di […]
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mkarcher wrote on 2024-02-08, 17:14:

fsinan wrote on 2024-02-08, 14:33:

WOW Great find, thank you. Mine is "2A4X5000C"...So it is fake...What happens if I change the bios? Does it boot? Later I'll change the chips.

Changing to the official BIOS does not hurt. Of course the message "256KB Cache" during boot will disappear as long as no cache is installed, but the official BIOS is fully prepared to work on a board without any working cache chips. You might get a BIOS complaint like "CACHE MEMORY BAD - DO NOT ENABLE CACHE", but IIRC that's a message on earlier BIOSes, and most likely AMI. If I remember wrong and you get that message with the original BIOS, just disable the L2 cache and you are fine.

I agree, the official 2A4X5H03C BIOS should work fine and will indicate the actual L2 cache size. With the fake chips it will display “None”. 😉

Because the 2A4X5000C only “fixes” the L2 cache size display to 256KB and doesn’t display any cache warning messages, I believe the 2A4X5H03C BIOS won’t complain about the fake L2 cache either.

Note that your BIOS is stored in a D27C010 128KB UV-EPROM chip and can’t be flashed.
Do you have an (E)EPROM programmer to program a new chip? It is usually easier to get a new 27C010 or equivalent (E)EPROM chip to program the official BIOS in, and keep the old BIOS chip as backup. It saves the hassle of erasing the old chip with UV-light first.

Cheers, Jan

Can I change D27C010 to a flashable bios chip?

fsinan wrote on 2024-02-09, 18:23:

Can I change D27C010 to a flashable bios chip?

Yes. Any usual 5V 128K x 8 flash chip will at least work like a ROM in that board. I don't know whether that board supports in-system flashing or you need to program the chip using a programmer or a different computer and doing a hot-swap flash.

fsinan wrote on 2024-02-09, 18:20:

But I will buy some real cache chips. I'm asking for that case.

yes, in that case "you wont gain anything by flashing official bios". Your fake bios will work fine with real cache.

Same combination of "cache" and "tag" chips:
https://youtu.be/NWUtn0mslgo?t=742

😁

Removed the fake chips. Still reporting 256K. Real ones on the way.

rasz_pl wrote on 2024-02-10, 00:18:

fsinan wrote on 2024-02-09, 18:20:

But I will buy some real cache chips. I'm asking for that case.

yes, in that case "you wont gain anything by flashing official bios". Your fake bios will work fine with real cache.

Today I installed a set of srams total of 512. Set the jumper, reporting 512 but did not boot into DOS, stalls after bios info screen before dos boot. Changed the set of SRAMS again it does not boot. When disabling cache from bios it boots.

Either I installed two sets of bad srams or there is something wrong with this "fake cache" bios.

Should I change the bios? What can I do to understand that these chips are real with multimeter?

picture of the chips installed?

Are the sram chips purchased from a "legit" place ?

because theres an large amount of fake chacke modules being sold everywhere... fuuny when replacing fake cache with not working cache..

weedeewee wrote on 2024-02-09, 17:02:

Chkcpu wrote on 2024-02-08, 19:09:

I agree, the official 2A4X5H03C BIOS should work fine and will indicate the actual L2 cache size. With the fake chips it will di […]
Show full quote

mkarcher wrote on 2024-02-08, 17:14:

Changing to the official BIOS does not hurt. Of course the message "256KB Cache" during boot will disappear as long as no cache is installed, but the official BIOS is fully prepared to work on a board without any working cache chips. You might get a BIOS complaint like "CACHE MEMORY BAD - DO NOT ENABLE CACHE", but IIRC that's a message on earlier BIOSes, and most likely AMI. If I remember wrong and you get that message with the original BIOS, just disable the L2 cache and you are fine.

I agree, the official 2A4X5H03C BIOS should work fine and will indicate the actual L2 cache size. With the fake chips it will display “None”. 😉

Because the 2A4X5000C only “fixes” the L2 cache size display to 256KB and doesn’t display any cache warning messages, I believe the 2A4X5H03C BIOS won’t complain about the fake L2 cache either.

Note that your BIOS is stored in a D27C010 128KB UV-EPROM chip and can’t be flashed.
Do you have an (E)EPROM programmer to program a new chip? It is usually easier to get a new 27C010 or equivalent (E)EPROM chip to program the official BIOS in, and keep the old BIOS chip as backup. It saves the hassle of erasing the old chip with UV-light first.

Cheers, Jan

Does the modified bios display the correct amount of cache when real cache is present, ie 64, 128, 256, 512K, or will it always display the fake 256K amount ?

Tried with 128K and 512K config, it shows the correct amount. But it hangs after "Starting MS-DOS"

fsinan wrote on 2024-03-21, 17:36:

weedeewee wrote on 2024-02-09, 17:02:

Chkcpu wrote on 2024-02-08, 19:09:

I agree, the official 2A4X5H03C BIOS should work fine and will indicate the actual L2 cache size. With the fake chips it will di […]
Show full quote

I agree, the official 2A4X5H03C BIOS should work fine and will indicate the actual L2 cache size. With the fake chips it will display “None”. 😉

Because the 2A4X5000C only “fixes” the L2 cache size display to 256KB and doesn’t display any cache warning messages, I believe the 2A4X5H03C BIOS won’t complain about the fake L2 cache either.

Note that your BIOS is stored in a D27C010 128KB UV-EPROM chip and can’t be flashed.
Do you have an (E)EPROM programmer to program a new chip? It is usually easier to get a new 27C010 or equivalent (E)EPROM chip to program the official BIOS in, and keep the old BIOS chip as backup. It saves the hassle of erasing the old chip with UV-light first.

Cheers, Jan

Does the modified bios display the correct amount of cache when real cache is present, ie 64, 128, 256, 512K, or will it always display the fake 256K amount ?

Tried with 128K and 512K config, it shows the correct amount. But it hangs after "Starting MS-DOS"

Did you buy ISSI61C1024 chips? One of those has 128kB. Tons of it are sold on Ebay, they are sold in 10ns and 15ns. 10ns is 100% re-labelled, because it never existed in this speed rating, only 12, 15, 20ns.
I lately bought 20 pieces of it from a Chinese seller, 8 of it were dead.
Do you have TL866II-Plus programmer? It is has a SRAM test functionality.
So when you test it with that and it fails, then you know 100% that the chip is not working.

Unfortunately when a SRAM chip passes the test, you don't know really, if it works, because it does not test the timing of the chip.
But still you can easily filter out the completely broken ones, so it is a great speedup in finding good chips. So I have now 12 chips and have to check, whether they are really good or not, .....

nuno14272 wrote on 2024-03-21, 17:21:

Are the sram chips purchased from a "legit" place ?

because theres an large amount of fake chacke modules being sold everywhere... fuuny when replacing fake cache with not working cache..

Bought them from ebay reseller, from china. Declared as new but these are not new pieces as I understand. Properly printed above and below and they seem to be legit.

Bios cache detection might be performed using slowest timings (the case in two bioses I disassembled), then bios applies your speed settings and its no longer stable.
You can try lowering FSB and setting slowest timings.

fsinan wrote on 2024-03-21, 18:23:

nuno14272 wrote on 2024-03-21, 17:21:

Are the sram chips purchased from a "legit" place ?

because theres an large amount of fake chacke modules being sold everywhere... fuuny when replacing fake cache with not working cache..

Bought them from ebay reseller, from china. Declared as new but these are not new pieces as I understand. Properly printed above and below and they seem to be legit.

I don't know if it is really interesting, but:
Those were the 20chips, I bought:

The upper 12 passed the SRAM test, the other 8 failed it.
When you have one that fails this test, it will not work, not even on 20MHz FSB. If you have a mainboard that supports such a low FSB. But most likely your chips are good in principle, but the can't keep up with the tight timing.
You should try 3-2-2-2 read and 3T write as a first thing always.

CoffeeOne wrote on 2024-03-21, 18:32:

I don't know if it is really interesting, but: Those were the 20chips, I bought: issi61C1024.jpg […]
Show full quote

fsinan wrote on 2024-03-21, 18:23:

nuno14272 wrote on 2024-03-21, 17:21:

Are the sram chips purchased from a "legit" place ?

because theres an large amount of fake chacke modules being sold everywhere... fuuny when replacing fake cache with not working cache..

Bought them from ebay reseller, from china. Declared as new but these are not new pieces as I understand. Properly printed above and below and they seem to be legit.

I don't know if it is really interesting, but:
Those were the 20chips, I bought: issi61C1024.jpg

The upper 12 passed the SRAM test, the other 8 failed it.
When you have one that fails this test, it will not work, not even on 20MHz FSB. If you have a mainboard that supports such a low FSB. But most likely your chips are good in principle, but the can't keep up with the tight timing.
You should try 3-2-2-2 read and 3T write as a first thing always.

Have you tried the cotton swab with nail polish remover(acetone) test on the printing of the IC ? best to try on the known broken ones first 😉

though maybe considering the amount of scratches on them, it's not necessary.

weedeewee wrote on 2024-03-21, 18:36:

CoffeeOne wrote on 2024-03-21, 18:32:

I don't know if it is really interesting, but: Those were the 20chips, I bought: issi61C1024.jpg […]
Show full quote

fsinan wrote on 2024-03-21, 18:23:

Bought them from ebay reseller, from china. Declared as new but these are not new pieces as I understand. Properly printed above and below and they seem to be legit.

I don't know if it is really interesting, but:
Those were the 20chips, I bought: issi61C1024.jpg

The upper 12 passed the SRAM test, the other 8 failed it.
When you have one that fails this test, it will not work, not even on 20MHz FSB. If you have a mainboard that supports such a low FSB. But most likely your chips are good in principle, but the can't keep up with the tight timing.
You should try 3-2-2-2 read and 3T write as a first thing always.

Have you tried the cotton swab with nail polish remover(acetone) test on the printing of the IC ? best to try on the known broken ones first 😉

though maybe considering the amount of scratches on them, it's not necessary.

No. But the broken ones are not interesting really. I am not interested, if they are fake or just not working. The seller refunded quickly the money for those. I wish they would (at least) test it with a TL866II by themselves, how hard it would it be?

We really need a rp2040/pico SRAM tester 😀

I've tried my 10 512K chips not sstematically but tried so many changes.

And tried 128K umc chips config with 10 chips with many configs, loosened the timings ...

I think there is a problem with Mboard, thats why they HAD to use fake chips with this one. To be able to solve it without problem even if l2 cache is enabled in bios.

Thats my idea.

fsinan wrote on 2024-03-21, 19:42:

I've tried my 10 512K chips not sstematically but tried so many changes. […]
Show full quote

I've tried my 10 512K chips not sstematically but tried so many changes.

And tried 128K umc chips config with 10 chips with many configs, loosened the timings ...

I think there is a problem with Mboard, thats why they HAD to use fake chips with this one. To be able to solve it without problem even if l2 cache is enabled in bios.

Thats my idea.

What do you mean with 512K chips and 128K chips???

CoffeeOne wrote on 2024-03-21, 20:09:

fsinan wrote on 2024-03-21, 19:42:

I've tried my 10 512K chips not sstematically but tried so many changes. […]
Show full quote

I've tried my 10 512K chips not sstematically but tried so many changes.

And tried 128K umc chips config with 10 chips with many configs, loosened the timings ...

I think there is a problem with Mboard, thats why they HAD to use fake chips with this one. To be able to solve it without problem even if l2 cache is enabled in bios.

Thats my idea.

What do you mean with 512K chips and 128K chips???

I'm talking about configs.

4 of 1024 chips and a 256k controller is 512K chips config.

5 of 256K chips(one is cont) is 128K chips config.