VOGONS


First post, by AlessandroB

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This base was directly inserted in socket4, what is its function? Can I omit it since a small leg broke?

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Reply 3 of 16, by derSammler

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Since there are only resistors on it, they are probably pull-up or pull-down resistors to fix bus signals.

It's made by IBM, so I would assume it's not something trivial that you can just omit. The broken pin can be fixed with some soldering; it's not a big issue to add a new pin there.

Reply 5 of 16, by AlessandroB

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rmay635703 wrote on 2020-02-01, 21:10:

Looks like an interposer.

Some early p60’s needed 5.5volts, the real early motherboard models are hard to find to verify

I have another Pentium1, a 66mhz version, can be the 66Mhz version better tolerate the lack of this interposer?

Reply 6 of 16, by derSammler

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Some early p60’s needed 5.5volts

No, they didn't "require" 5.5V, they were all rated for 5V. Some only needed a bit more voltage to make them more stable. Also, you wouldn't need that many resistors just to get the Vcore voltage down to 5V on a mainboard that supplies 5.5V.

Reply 7 of 16, by matze79

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Bus Terminator.

https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de - under constructing since ever

Co2 - for a endless Summer

Reply 10 of 16, by AlessandroB

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The pins of this adapter are not "malleable" like those of the CPUs, they break much much more easily. I have, however, discovered that I have what you see in the picture, I can unsolder the PINs from this strip to resold them in the adapter, which apart from having lost a few pins I think is perfectly functional

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Reply 12 of 16, by AlessandroB

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derSammler wrote on 2020-02-01, 22:08:

What I conclude as well. It fixes a design flaw in the mainboard it came with. If it is that, the resistors are there to avoid signal reflections on the bus.

Can you show us the mainboard?

this is before the "falling CPU" to the ground...

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Reply 13 of 16, by Deunan

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Whoa, what a routing mess. And the CPU is stuck in a corner, which (considering how many data pins the Pentium has) didn't help either. This is probably some early attempt at a Pentium mobo from someone who only did 486 or slower CPUs before that. The faster and wider bus was probably too much and there were glitches, so this interposer is there to deal with it. The mobo might even work without it but not be stable.

Reply 14 of 16, by lost77

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Didn't the Socket 4 OverDrive processors need an adapter on some motherboards? Never seen one of those, could be someone downgraded the CPU at one point and thought the adapter was needed for the motherboard.

Reply 15 of 16, by Horun

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Date codes on many chips are mid-late 1994, Pentium 60 debut was early 1993. I think Deunan is correct in it is needed for that specific board with it's EISA style extended Expansion slot and they probably had issues that needed some type termination for signal smoothing.

Hate posting a reply and have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. 🤣 Second computer a 286 12Mhz with real IDE drive ! After that came 386, 486, Pentium, P.Pro and everything after....

Reply 16 of 16, by AlessandroB

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Deunan wrote on 2020-02-01, 22:50:

Whoa, what a routing mess. And the CPU is stuck in a corner, which (considering how many data pins the Pentium has) didn't help either. This is probably some early attempt at a Pentium mobo from someone who only did 486 or slower CPUs before that. The faster and wider bus was probably too much and there were glitches, so this interposer is there to deal with it. The mobo might even work without it but not be stable.

Also P90- P100-P133 has this exact internal chip design.