VOGONS


Reply 20 of 24, by Rauli

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Mithloraite wrote:

As per the commentary, it's Memdump.exe program.

Thanks. If it dumps the memory, I should obtain the same file than I got (see my previous post)... and it is very different than the file you uploaded. Anyway I will try to dump the EPROM using MEMDUMP utility in your link and compare again.

Mithloraite wrote:

By the looks of it it worked with no problem. What I know this board can surely create fantastic CPU compatibility poblems.
I launched it with a Ti 'SXL' 40 Mhz CPU that seems to be the original unit on this board (and 4x1 mb 30 pin simms.)

Which socket does the TI SXL use? The 386 socket or the 486 socket? And, did you manage to install any CPU on the other socket? I ask because I have found people who can use only the 386 socket, and people (including me) who can use only the 486 socket, but no board seems to support both. I tried with both 30-pin and 72-pin memory modules.

Reply 21 of 24, by Anonymous Coward

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There must be some resistor packs or soldered shut jumpers that determine the CPU type. Either that or a special BIOS.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 22 of 24, by Rauli

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I have used MEMDUMP. It does a memory dump... but in the correct physical addresses, so it gets the real contents of the EPROM chip. And it is... exactly the same as the file that Mithloraite uploaded.

I have also taken a look at the soldered or missing jumpers and resistor packs.
1st: All the jumpers in the manual are really installed (with jumper heads), so the board can be configured for any supported CPU, so 386 CPUs should work... but they don't.
2nd: All the resistor packs and soldered or missing jumpers (which are not mentioned in the manual) are in the same state than the photo of the board posted by another user, with a 386 and a 387 installed and working... and telling that he can't use 486 CPUs.

What I would like to know: Is the TI SXL 40 installed on the 386 socket or on the 486 socket? (I have found contradictory information about this CPU, PGA 132 according to some, PGA 168 according to some other).

EDIT: I have seen the official Texas Instrument manual for the TI486SXL and it was made in both packagings:
PGA 132, for 386 socket (compatible with a TI or Cyrix 486DLC)
PGA 168, for 486 socket (compatible with an i486SX)

Reply 23 of 24, by Mithloraite

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Rauli wrote:

Which socket does the TI SXL use? The 386 socket or the 486 socket? And, did you manage to install any CPU on the other socket?... I tried with both 30-pin and 72-pin memory modules.

It is good to know that 30/72 pin memory is not a factor in the mysteries of this board 😀 My Ti SXL installed on this board is a 386 socket variation. Once I made a photo of it. Please see it.

http://imgur.com/bhF9nvM

What is of iterest is the label "Ti SXL only" beside the 486 socket. It's a LIF uncomfortable pull-up socket and normal 486 CPUs should not work. The label is probably correct because some jumpers are factory hard-wired/non configurable.
So I never tried to use this 'specialized' socket.

Rauli wrote:

I ask because I have found people who can use only the 386 socket, and people (including me) who can use only the 486 socket, but no board seems to support both.

It seems even when we see no label on some boards the 486 socket can also be "special" or non-functional.

If not the BIOS (as you have dumped the same BIOS) - can it be a PCB revision or some component revision that is so critical?

Perfection is the key. Fatality is the key. (c)

Reply 24 of 24, by Rauli

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Thanks for the photo. My board looks like the same, silkscreened "DataExpert EXP4349 Ver 1.0" with the same components and the same missing components.

Differences:
Somebody replaced the original barrel battery with a new one.
All the jumpers around the CPU sockets, and between 2nd and 3rd expansion slots, have jumpers installed.
My 486 socket is a ZIF, instead of a LIF.
I have 8 cache chips, instead of 4, and the cache TAG chip (at the right of keyboard controller) is like the cache chips (W24257AK-15).

It's clear that 1st, 2nd and 3rd differences can't prevent the 386 socket to be used.
The 4th one shouldn't be a problem either, but who knows? I can remove 4 of the cache chips, but with that cache configuration I should change the TAG chip and I don't have one of the proper type, so I can't do this test.

(The photo in the 1st post of this thread shows a photo of a board like mine, with jumpers, ZIF socket and 8 cache chips... and opposite problem than mine)