Author Topic: Polymer recaps  (Read 221 times)

Offline lepidotos

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Polymer recaps
« on: November 23, 2021, 09:07:29 PM »
I have yet to recap any of my Macs, but I'm interested in doing so -- all of them date to the capacitor plague, and I'd rather not lose any of them to corrosion. According to a guy on Vogons, using solid state caps made his Pentium 4 "noticeably quicker and snappier in everything it did", and I'm curious if that applies to, say, a 7400 as well. If not, it would still be something I'd do for longevity's sake, but I'd like to hear others weigh in.

Offline robespierre

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Re: Polymer recaps
« Reply #1 on: November 23, 2021, 09:39:06 PM »
I'm afraid that doesn't make any sense from a technical perspective. Large value capacitors are used as local energy reservoirs, referred to by engineers as "bypass capacitors". When digital circuits switch on and off, they draw momentary bursts of current, which would appear as noise on the power supply lines if there was nothing to suppress them. Those bursts of noise if uncontrolled could lead to incorrect operation. The capacitors "absorb" noise because they keep the power supply lines at a constant voltage. When a device draws a burst of current, the current comes out of a nearby bypass capacitor instead of traveling down the entire length of the power supply line. This function does not have any influence on the processing speed, which is entirely controlled by a network of clock generators on each chip and disciplined to a master oscillator.

Polymer electrolytics are several times the cost of wet aluminum electrolytic capacitors and do exactly the same thing in a circuit. They have the advantage that without any liquid electrolyte they cannot leak. They also have a better ESR figure, which can be exploited by designers to pack power-hungry components closer together. This difference has no advantage in repairing of electronics that do not require it.

It reads more like the kind of audiophoolery that believes that "exotic" components (silver solder, cable lifts, braided power cables) improve sound quality.

Offline GaryN

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Re: Polymer recaps
« Reply #2 on: November 24, 2021, 08:33:23 AM »
All right robespierre! It's great to see someone who not only knows what he's talking about, but can present it coherently as well.

"Audiophoolery" is a constant PITA that's been around as long as there has been recorded audio.
This is simply a variation - we'll call it "electrophoolery".
The perception (deception) that stuff "sounds better" after replacing the usual with the exotic is a combination of wanting the exotic to work and the subconscious resistance to not hearing an improvement after spending an obscene amount of money on it.

Cable lifts……  :o :o :o  Aarrgh!

Offline DieHard

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Re: Polymer recaps
« Reply #3 on: November 24, 2021, 08:48:13 AM »
Gary,

Don't be so cynical, that wire is a steal because it comes with "FREE" anti-rat coating :)

Offline GaryN

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Re: Polymer recaps
« Reply #4 on: November 24, 2021, 04:18:38 PM »
You think? My rats ate the damn wire anyway and now they can hear my cat sneaking up on them…  >:(

Offline lepidotos

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Re: Polymer recaps
« Reply #5 on: November 26, 2021, 09:17:04 PM »
Probably the best answer to my stupid question, thanks!

 


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