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Curious Socket 370 (factory?) mod on MSI 694D Pro Motherboard (LINT1 connected to VSS)

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First post, by appiah4

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I was recapping some swollen 1500uF Teapos on my 694D Pro when I realized that both Socket 370s have a very curious looking modification.

The L37 (LINT1) pin is connected to K36 (VSS) with what seems to be a blob of solder.

I initially assumed this was done by the previous user to mod them for use with Tualatins but Googling this did not yield any known Tualatin mods of this kind. Moreover, I believe Talatin PIIIs are not SMP capable? At least in this board?

Regardless, I have found some discussion on the board regarding some slotkets having this as a factory mod with a capacitor between the pins. The speculation appears to be that this is for making detection of certain CPUs possible on Slot-1 boards?

That led me to think this is actually factory made.. But I don't quite understand what for. Any ideas?

Reply 1 of 4, by appiah4

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Really no one has any answers?

Reply 2 of 4, by shevalier

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appiah4 wrote on 2026-04-25, 07:42:

Really no one has any answers?

Well, it’s worth taking a look at the typical schematic diagram for the VIA694

Or the "classic" reference schematic from Intel for I815
https://elektrotanya.com/intel_815df_rev_a_sc … f/download.html

Aopen MX3S, PIII-S Tualatin 1133, Radeon 9800Pro@XT BIOS, Audigy 4 SB0610
JetWay K8T8AS, Athlon DH-E6 3000+, Radeon HD2600Pro AGP, Audigy 2 Value SB0400
Gigabyte Ga-k8n51gmf, Turion64 ML-30@2.2GHz , Radeon X800GTO PL16, Diamond monster sound MX300

Reply 3 of 4, by appiah4

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shevalier wrote on 2026-04-25, 07:51:
Well, it’s worth taking a look at the typical schematic diagram for the VIA694 […]
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appiah4 wrote on 2026-04-25, 07:42:

Really no one has any answers?

Well, it’s worth taking a look at the typical schematic diagram for the VIA694

Or the "classic" reference schematic from Intel for I815
https://elektrotanya.com/intel_815df_rev_a_sc … f/download.html

Although I can't really tell what it's doing it looks like LINT1 is connected to -SM, which in turn is connected to ground through a 56pf capacitor (connected directly to ground through a 0.1pf capacitor in i815's case). My understanding is that the board, for some reason, did not account for this grounding and had to bodge it on the socket? Probably an engineering oversight? Or maybe this requirement was not there for earlier coppermines and got introduced later on? Strange.

Reply 4 of 4, by shevalier

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appiah4 wrote on 2026-04-27, 06:21:
shevalier wrote on 2026-04-25, 07:51:
Well, it’s worth taking a look at the typical schematic diagram for the VIA694 […]
Show full quote
appiah4 wrote on 2026-04-25, 07:42:

Really no one has any answers?

Well, it’s worth taking a look at the typical schematic diagram for the VIA694

Or the "classic" reference schematic from Intel for I815
https://elektrotanya.com/intel_815df_rev_a_sc … f/download.html

Although I can't really tell what it's doing it looks like LINT1 is connected to -SM, which in turn is connected to ground through a 56pf capacitor (connected directly to ground through a 0.1pf capacitor in i815's case). My understanding is that the board, for some reason, did not account for this grounding and had to bodge it on the socket? Probably an engineering oversight? Or maybe this requirement was not there for earlier coppermines and got introduced later on? Strange.

From what I can see, the NMI signal comes directly from the South Bridge, or via 74-series discrete logic, which (attempts to) override the CPU multiplier if it is not locked.
For the 694TAS, jumper JP2 is not mentioned at all in the description, so shorting the NMI to ground via a capacitor is purely a test procedure.
https://theretroweb.com/motherboard/manual/69 … ae414604695.pdf

Aopen MX3S, PIII-S Tualatin 1133, Radeon 9800Pro@XT BIOS, Audigy 4 SB0610
JetWay K8T8AS, Athlon DH-E6 3000+, Radeon HD2600Pro AGP, Audigy 2 Value SB0400
Gigabyte Ga-k8n51gmf, Turion64 ML-30@2.2GHz , Radeon X800GTO PL16, Diamond monster sound MX300

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