VOGONS


First post, by assasincz

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Hi all,

My first post here - Nostalgia got to me recently, so I decided to build myself a shiny new-ish 486 setup to play with
I got a PC with Shuttle HOT-419 DZ R2 mainboard with Intel DX20DPR66 CPU accompanied by 2pcs of not-identical 4MB 72pin SIMM in banks 0 and 1.
With a faster CPU being is on its way, in the meantime, I wanted to upgrade the RAM to more than 8 megs.

I got a 5pc bunch of identical non-branded 16MB double-sided 72-pin SIMM modules (don't know if they are EDO, or FPM, nice condition but unknown if working), and had high hopes, since the MB manual I found (multiple sources) say that it supports up to 64MB modules and up to 128MB total.

Needless to say, not one of the 5pcs work, the PC does not post with any of them.
I tried working on jumpers' settings, trying modes with 4 banks and with 3 banks, to no avail.

Even with same module on multiple power-ups, one time the speaker beeps (long low-pitch repeating buzz), the other time it does not, and at no time does to screen come on.
When pairing with working modules that were already there, again, no post.

Either all of the five units are dead (I doubt), or I am doing something wrong which is obscure to me, can you advise? What could be the issue?

Reply 1 of 4, by gerwin

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-Are you sure your 486 can handle EDO RAM? 486s normally insist on FPM.
-You can check whether or not your sticks are EDO or FPM yourself. Reading the markings on the memory chips and enter them in a search engine to look for a datasheet.

--> ISA Soundcard Overview // Doom MBF 2.04 // SetMul

Reply 2 of 4, by assasincz

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gerwin wrote:

-Are you sure your 486 can handle EDO RAM? 486s normally insist on FPM.
-You can check whether or not your sticks are EDO or FPM yourself. Reading the markings on the memory chips and enter them in a search engine to look for a datasheet.

The chips are marked HY5117405BJ-60, I could not find an exact match datasheet,

However I found HYB 5117405BJ-60 which seem to be EDO 😐
The package size is the same
http://pdf.datasheetcatalog.com/datasheet/inf … /1-hb17405c.pdf

Case closed then?

I intend to use these SIMMs eventually with A80486DX4-10SV8B CPU, is there any chance it might work?

Reply 3 of 4, by gerwin

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assasincz wrote:

I intend to use these SIMMs eventually with A80486DX4-10SV8B CPU, is there any chance it might work?

CPU does not matter in this regard. It is the motherboard chipset that has to support RAM of the EDO type. It seems your board has an OPTi 895 chipset. I don't know the particulars of this one.

Also there is another issue: The datasheets you linked to mention 3,3 Volt instead of 5 Volt.

--> ISA Soundcard Overview // Doom MBF 2.04 // SetMul

Reply 4 of 4, by assasincz

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Sorry that was supposed to be A80486DX4-120SV8B CPU...120mhz
Well, I could not find a specific mention of OPTi 895 supporting EDO, only a past rig sale on Ebay claiming that with same board as mine, there are 4MB EDO SIMMs, apparently working

https://www.ebay.ie/itm/Shuttle-HOT-419-OPTi- … M-/273084888984

The SIMMs which are already in the machine working seem to be FPM, I think this is the right track