VOGONS


First post, by protivakid

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I found an old post where a user was able to manually solder cache onto an OEM Intel NV430VX here: www.oocities.org/sjg/upgrade/cache.html

Besides the chips, he had to add several resistors as he documented here:

  • R1E4 (22 ohm) -clock feed, series termination
    C1E6 (4.7pf to 22pf) -EMI reducing capacitor
    R2D1 (10k ohm) -provides Enable #2 (CE2)
    R2F1 (220 ohm) -provides /Enable #3 (/CE3)
    R4D4 (0 ohm) -provides /OE for Tag RAM
    R4D5 (0 ohm) -provides 5v for Tag RAM (note: R4D1 is used if 3.3v Tag RAM is used)
    C4D1 (.1uf) -decoupling/bypass capacitor
    R3F2 (10k ohm) -MS to V+.

He said he was able to figure out all of this information by using these two guides:
Intel NV430VX Motherboard Technical Product Specification (August 1996) - www.elhvb.com/mobokive/archive/power_ut ... 182101.pdf
Intel 430VXPCIset Design Guide (June 1997) - ftp://ftp.efe.hu/doc/297469.pdf

I am looking to do the same with an OEM Intel 430TX. Using his post as a guide, what I can't figure out is how from just the two guides linked above, he was able to (A) determine resistor values, and (B) determine resistor location.

Can any of you make sense of this?

Last edited by protivakid on 2018-12-06, 15:26. Edited 1 time in total.

Reply 1 of 9, by Mister Xiado

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As an electronic engineer, I understand the concepts, but my question is, "is it worth the time and effort"? Either way, I believe the first step would be to check the data sheets for the chips(s) being added, to at least see what the expected voltage levels would be for each input, and compare that with the line voltages on the board that would be going to the leads. When it comes to capacitors, as long as the voltage rating and the capacitance value of the capacitor exceeds what you need, you're not likely to have any magic smoke festivals. Might save a lot of time if you can find someone with a similar or identical board already outfitted with the cache memory you intend to add.

b_ldnt2.gif - Where it's always 1992 (or so).
Icons, wallpapers, and typical Oldternet nonsense.

Reply 2 of 9, by protivakid

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Mister Xiado wrote:

As an electronic engineer, I understand the concepts, but my question is, "is it worth the time and effort"? Either way, I believe the first step would be to check the data sheets for the chips(s) being added, to at least see what the expected voltage levels would be for each input, and compare that with the line voltages on the board that would be going to the leads. When it comes to capacitors, as long as the voltage rating and the capacitance value of the capacitor exceeds what you need, you're not likely to have any magic smoke festivals. Might save a lot of time if you can find someone with a similar or identical board already outfitted with the cache memory you intend to add.

Hey, this is totally just a project for fun to see if I can do it. I actually do have the same non-OEM board with cache, I just want to see if I can add it to the OEM version.

As far as identifying resistor / capacitor spots, I can visually see where the board with cache has extras soldered on but am unsure which extras relate to L2 cache and not various other components. The chips run at either 5v or 3.3v, you can select between depending on which chips you go with. I already have the memory chips and tag ram figured out. At this point my hurdle is the extra resistors and where exactly to place them. He makes it sound like from the two linked guides he was able to determine exactly this.

Reply 3 of 9, by Mister Xiado

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Well, you have the same URL there twice, and the L2 Cache section just mentions the variants available. Macro photos of the modified board would at least let you see the traces and components between chips, if nothing goes diving under or within the motherboard. For instance "resistor with value X is added inline with pin Y on chip Z". God, I don't even want to think about cutting a trace on a motherboard to splice in another component.

b_ldnt2.gif - Where it's always 1992 (or so).
Icons, wallpapers, and typical Oldternet nonsense.

Reply 4 of 9, by protivakid

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Mister Xiado wrote:

Well, you have the same URL there twice, and the L2 Cache section just mentions the variants available. Macro photos of the modified board would at least let you see the traces and components between chips, if nothing goes diving under or within the motherboard. For instance "resistor with value X is added inline with pin Y on chip Z". God, I don't even want to think about cutting a trace on a motherboard to splice in another component.

Fixed the link, my bad with that one 😀

The only other document I found was the "INTEL 430VX PCISET 82437VX SYSTEM CONTROLLER (TVX)" guide here: intel-vintage-developer.eu5.org/DESIGN/ ... 055301.PDF

Other than using pictures of both boards, am I nuts to think that from just the two documents linked in the first post alone, that neither of these gives resistor values and solder locations?

Reply 5 of 9, by Mister Xiado

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The documentation just seems to be barebones, end user copy, and nothing so advanced as to facilitate manual upgrades using additional components.

b_ldnt2.gif - Where it's always 1992 (or so).
Icons, wallpapers, and typical Oldternet nonsense.

Reply 6 of 9, by protivakid

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Mister Xiado wrote:

The documentation just seems to be barebones, end user copy, and nothing so advanced as to facilitate manual upgrades using additional components.

Thanks for confirming. Any idea what the [number:number] mean in the Intel 430VXPCIset Design Guide (June 1997)? I see for example AD[31:0] on the pinouts of chips but don't know what the numbers mean.

Reply 7 of 9, by protivakid

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Any other electrical engineers have any input?

If not how about this question, there are some surface mount resistors on the board that have a color on them but no text. How can I tell what values these are?

Reply 8 of 9, by Tiido

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x[y:z] mark signal ranges, i.e the AD[31:0] refers to all AD lines between and including 31 and 0.

The brownish colored parts are capacitors and you won't really know their value unless you measure them. Usually they are 0.1µF.

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Reply 9 of 9, by protivakid

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Tiido wrote:

x[y:z] mark signal ranges, i.e the AD[31:0] refers to all AD lines between and including 31 and 0.

The brownish colored parts are capacitors and you won't really know their value unless you measure them. Usually they are 0.1µF.

Thanks for the help. Looks like a multimeter and a magnifying glass will be needed to compare boards. I was hoping like the original guy claimed that the design documents would provide all I need but that doesn't seem to be the case at all.