VOGONS


First post, by Intel486dx33

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Can I use ceramic capacitors in place of tantalum capacitors on my 486 motherboard ?
What are the pros and cons ?

Reply 1 of 7, by GigAHerZ

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Depends, but why should you do that?

"640K ought to be enough for anybody." - And i intend to get every last bit out of it even after loading every damn driver!

Reply 2 of 7, by rasz_pl

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mlcc capacity is more of a guideline than a hard stat, it changes with bias voltage https://www.murata.com/en-us/support/faqs/pro … /mlcc/char/0005
then you have high defect rate in high mechanical stress scenarios (smd cap + flexing board = actual real world house burning FIRE)

but for motherboard decoupling? sure

Edit: forgot to mention mlcc also like to make noise, and exhibit microphonics, still non issue for old motherboard decoupling

Reproductions
https://github.com/raszpl/FIC-486-GAC-2-Cache-Module for AT&T Globalyst
https://github.com/raszpl/386RC-16 memory board
RE
Zenith Data Systems (ZDS) ZBIOS 'MFM-300 Monitor'

Reply 3 of 7, by Mut

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Replace those old tantaluns with eletrolytic caps, they are cheap and reliable. I've always had success doing it.

Reply 4 of 7, by Intel486dx33

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I think I will just use the original tantalum capacitors.

Reply 5 of 7, by rasz_pl

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Mut wrote:

Replace those old tantaluns with eletrolytic caps, they are cheap and reliable. I've always had success doing it.

there are different uses for different types, cant just blindly swap and expect it to work
https://electronics.stackexchange.com/questio … ferences-in-use

Reproductions
https://github.com/raszpl/FIC-486-GAC-2-Cache-Module for AT&T Globalyst
https://github.com/raszpl/386RC-16 memory board
RE
Zenith Data Systems (ZDS) ZBIOS 'MFM-300 Monitor'

Reply 6 of 7, by gdjacobs

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Polymers and MLCCs are both appropriate (and manufacturer recommended) replacements for tantalum caps. Of course, please beware of the propensity of ceramic caps to fail short and generate microphonics.

All hail the Great Capacitor Brand Finder

Reply 7 of 7, by Mut

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Intel486dx33 wrote:

I think I will just use the original tantalum capacitors.

Tantaluns are prone to fail catastrophically and are not recommended.

Electrolytics and tantalus have similar characteristics.

On the past I had two identical 386 motherboards (I don't remember the model) but from different batches, one using tantaluns and the other one using electrolytic.