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Smallest 486 MOBO (M921)

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First post, by cimbalino

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Smallest 486 MOBO I've seen

JaNoZ wrote on 2013-07-11, 19:24:
I got the board and did some fake shit removal. […]
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I got the board and did some fake shit removal.

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Do you notice the empty smd capacitors spots like CB7 near the power connectors, should there be any capacitors installed if i put in sockets and real cache chips.
Can anyone confirm with having the same board layout and real cache ?

Sorry to dig out this old post

I´ve adquired a M921 with a 486dx4-120Mhz and the fake chip cache and I would like to know if you could get the cache working by simply adding the real cache chips.
I already removed the fake chips and I´m preparing to add the sockets. Is it necessary to add also the capacitors?

Thank you

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Last edited by Stiletto on 2020-05-15, 08:24. Edited 1 time in total.

Reply 1 of 8, by Deksor

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I don't have this specific board, but I've done this kind of mod twice successfully with two boards that had fake cache (a pcchips an a "full yes tech") without changing anything else (not even the BIOS).
Now maybe yours will need capacitors to work, but I * think * it'll be ok.

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Reply 3 of 8, by cimbalino

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Deksor wrote on 2020-04-27, 23:41:

I don't have this specific board, but I've done this kind of mod twice successfully with two boards that had fake cache (a pcchips an a "full yes tech") without changing anything else (not even the BIOS).
Now maybe yours will need capacitors to work, but I * think * it'll be ok.

Dektor, thank you for your feedback!!
it gave me the confidence to carry on with it 😀

Reply 4 of 8, by cimbalino

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Thank you for the reply

maxtherabbit wrote on 2020-04-28, 00:15:

I would definitely add the bypass caps, we're talking pennies and they make IC operation more reliable

Cool,

I really appreciate your advice.
I´ll try to do it, but i´m starting in electronics so some things are new to me. Also I´ve researched about the type of capacitors you´ve referred but i can´t find it for sale (at least, with that designation).
Can you please give me a little bit more information? (they´re specifications, etc, etc)

Thank you

Reply 6 of 8, by Deunan

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cimbalino wrote on 2020-04-27, 20:53:

I already removed the fake chips and I´m preparing to add the sockets. Is it necessary to add also the capacitors?

You mean the SMD C87-C90? I'd try, the cache chips are fast-switching and generate a lot of noise on the power lines. These caps will help filter that out - for both the cache and the rest of the mobo.
100nF should be enough, 1uF if you can find one that fits. Anything 6V3 or higher will do but preferably pick 10V or 16V if you can.

Reply 8 of 8, by BLockOUT

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cimbalino wrote on 2020-04-30, 21:00:

Thank you very much for all of your suggestions.

I´ll try them out and post the results.

did it work?
i have one of these, and im taking the fake chips out and buying sockets

only sockets i found were 28pin but some slots can take up to 32 pin chips

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