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This forum is part of our mission to promote the preservation of vintage computers through education and outreach. (In real life we also run events and have a museum.) We encourage you to join us, participate, share your knowledge, and enjoy.

This forum has been around in this format for over 15 years. These rules and guidelines help us maintain a healthy and active community, and we moderate the forum to keep things on track. Please familiarize yourself with these rules and guidelines.


Remain civil and respectful

There are several hundred people who actively participate here. People come from all different backgrounds and will have different ways of seeing things. You will not agree with everything you read here. Back-and-forth discussions are fine but do not cross the line into rude or disrespectful behavior.

Conduct yourself as you would at any other place where people come together in person to discuss their hobby. If you wouldn't say something to somebody in person, then you probably should not be writing it here.

This should be obvious but, just in case: profanity, threats, slurs against any group (sexual, racial, gender, etc.) will not be tolerated.


Stay close to the original topic being discussed
  • If you are starting a new thread choose a reasonable sub-forum to start your thread. (If you choose incorrectly don't worry, we can fix that.)
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To put things in engineering terms, we value a high signal to noise ratio. Coming here should not be a waste of time.
  • This is not a chat room. If you are taking less than 30 seconds to make a post then you are probably doing something wrong. A post should be on topic, clear, and contribute something meaningful to the discussion. If people read your posts and feel that their time as been wasted, they will stop reading your posts. Worse yet, they will stop visiting and we'll lose their experience and contributions.
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"PM Sent!" messages (or, how to use the Private Message system)

This forum has a private message feature that we want people to use for messages that are not of general interest to other members.

In short, if you are going to reply to a thread and that reply is targeted to a specific individual and not of interest to anybody else (either now or in the future) then send a private message instead.

Here are some obvious examples of when you should not reply to a thread and use the PM system instead:
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Why do we have this policy? Sending a "PM Sent!" type message basically wastes everybody else's time by making them having to scroll past a post in a thread that looks to be updated, when the update is not meaningful. And the person you are sending the PM to will be notified by the forum software that they have a message waiting for them. Look up at the top near the right edge where it says 'Notifications' ... if you have a PM waiting, it will tell you there.

Copyright and other legal issues

We are here to discuss vintage computing, so discussing software, books, and other intellectual property that is on-topic is fine. We don't want people using these forums to discuss or enable copyright violations or other things that are against the law; whether you agree with the law or not is irrelevant. Do not use our resources for something that is legally or morally questionable.

Our discussions here generally fall under "fair use." Telling people how to pirate a software title is an example of something that is not allowable here.


Reporting problematic posts

If you see spam, a wildly off-topic post, or something abusive or illegal please report the thread by clicking on the "Report Post" icon. (It looks like an exclamation point in a triangle and it is available under every post.) This send a notification to all of the moderators, so somebody will see it and deal with it.

If you are unsure you may consider sending a private message to a moderator instead.


New user moderation

New users are directly moderated so that we can weed spammers out early. This means that for your first 10 posts you will have some delay before they are seen. We understand this can be disruptive to the flow of conversation and we try to keep up with our new user moderation duties to avoid undue inconvenience. Please do not make duplicate posts, extra posts to bump your post count, or ask the moderators to expedite this process; 10 moderated posts will go by quickly.

New users also have a smaller personal message inbox limit and are rate limited when sending PMs to other users.


Other suggestions
  • Use Google, books, or other definitive sources. There is a lot of information out there.
  • Don't make people guess at what you are trying to say; we are not mind readers. Be clear and concise.
  • Spelling and grammar are not rated, but they do make a post easier to read.
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Undervolting fans

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    Undervolting fans

    For a while now I've been taking higher voltage fans (DC brushless) with high CFM and undervolting them so that they have close to the same CFM as the original fan but are far quieter. For example replacing a 12v 80mm fan with a 24v version. Doesn't provide as much of a breeze but still drafts air through a 486 box.
    Someone said I shouldn't do that because they draw more amps and it can burn the motor driver out. I have not done prolonged testing but does sound like a thing?
    [Need something to waste time on? Click here to visit my YouTube channel CelGenStudios]
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    = Excellent space heater

    #2
    Nah, I've got a couple of setups here using 24V fans with 12V supply--as well as 12V fans on 5V supply. They work fine, albeit with lower airflow but a lot quieter. Heck, I've even got a 240VAC fan running from 120V--allowed me to keep my sanity, while maintaining sufficient airflow. Apparently, some of the RPi folks are taking 5V fans and running them on 3.3V.

    Anent the last, any recommendations for a 40 mm DC fan that will last and doesn't cost an arm and a leg?

    Comment


      #3
      While running motors at a lower voltage can be a problem in some cases, it's generally not in the case of brushless computer fans. They already run hot to begin with, when's the last time you saw a computer fan with a ventilated hub? The coils run smokin hot at normal voltages.

      Where you may run into trouble are PWM fans, which have more active circuitry in them that may behave erratically at lower voltages.

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        #4
        Originally posted by NeXT View Post
        Someone said I shouldn't do that because they draw more amps and it can burn the motor driver out. I have not done prolonged testing but does sound like a thing?
        That's completely nonsense and apparently claimed by someone who never heared about the Ohm's law. At half the voltage, they will also only draw half the current. That guy probably thought it will always have the given power in watts no matter what. But that's not how things work.

        The only real downside you have with undervoltage is that the fan may sometimes just not start spinning.

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