Forum Rules and Etiquette

Our mission ...

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.

Rule 1: 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.

Rule 2: 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.)
  • If you are responding to a thread, stay on topic - the original poster was trying to achieve something. You can always start a new thread instead of potentially "hijacking" an existing thread.

Rule 3: Contribute something meaningful

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.
  • Do not bump threads.
  • Do not "necro-post" unless you are following up to a specific person on a specific thread. And even then, that person may have moved on. Just start a new thread for your related topic.
  • Use the Private Message system for posts that are targeted at a specific person.

Rule 4: "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:
  • "PM Sent!": Do not tell the rest of us that you sent a PM ... the forum software will tell the other person that they have a PM waiting.
  • "How much is shipping to ....": This is a very specific and directed question that is not of interest to anybody else.

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.

Rule 5: 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.
See more
See less

A couple of power supply questions...

  • Filter
  • Time
  • Show
Clear All
new posts

    A couple of power supply questions...

    I've got some repair questions regarding ATX P4 power supplies.

    One is weak. In a machine with a CD-RW drive and a DVD drive the CD works fine but whenever I put a DVD into its drive the machine reboots. I determined that it was the power supply. Everything works fine with a new power supply. Any suggestions what to look for in this weak power supply to try and repair it?

    The other power supply is a no-go. The power button goes amber when I try to start the machine. There is no fan action. The only life other than the power button is the green pilot light on the motherboard. Any suggestions for a repair on this one?

    Thanks in advance.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

    I'd say about 90% of the time it's just bad capacitors. Sometimes you'll get a shorted rectifier or switching transistor, but such issues are considerably less common.


      I don't have a cap checker, only a VOM. Is there any way to check caps with that?
      PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step


        Not really. To be able to properly test 'em you'd need an ESR meter.

        But have you actually pulled the covers and looked inside the units yet? Usually the caps bulge when they go bad, and are thus pretty easy to spot.

        Also, what specific PSUs are they? Chances are pretty good that I've repaired at least one or two of the same models, so I may be able to offer specific pointers for your units...


          It's not a perfect test (ESR is today's method) but you can do a simpler test of caps with a digital multimeter it just won't be able to prove if the cap is able to hold the full potential load that it's meant to. Think of this as the poor man's test.
          Looking to acquire: IBM 5100, Altair 8800


            One is from a Gateway. It's a Newton Power Ltd., Model: NPS-160CB-1 A REV:00 and it's the totally bad one. Nothing obvious upon visual inspection. No burns, scorching or bulging, disfigured or leaking caps.

            The other is a MAX Model: ESP:300 and it works except the machine reboots upon DVD insertion. It has a few caps that ‘may’ be bulging just a bit and are therefore suspicious.
            PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step


              Think of this as the poor man's test.
              It's also of limited use on this sort of equipment, since caps will often still show full capacitance but have a high ESR, and ESR is quite an important factor here.

              The Newton units are good quality, and shouldn't have any problems with capacitors... I've only ever come across one dead one, and it had been hit by a power surge. You said you tried a different PSU in the one system, but did you do the same for this one?

              I'd also try hooking up a couple old drives or something to put a bit of a load on it, then power it up outside the machine (jump the green wire in the ATX connector to one of the ground wires with a paperclip or something) and see what happens...

              The ESP-300 model number sounds like it might be a rebranded Channelwell unit, but I'm not sure on that. Can you get a picture of the inside of it? It definitely does sound like bad caps on this one.


                It's all the same system, a Gateway, and it came with the Newton. The Newton does nothing when tested as you described. It even has a test button with a green pilot light that does nothing either.

                I think the ESP-300 is just the regular Chinese junk, by any name. But, hey, it still partially works. Probably not much longer, though, without some caps.
                PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step


                  in all honesty, I haven't found it worth the trouble to fix ATX power supplies. At least not "standard" ones. I've done it once, to a 350w unit, but it was special. It had extremely high 5/3.3V rails and I needed it for a special project. It was HELL to replace the secondary caps. Took all afternoon. These little supplies are high quality and just plain work for older systems.

                  The power efficiency and stability of the latest units is practically unbeatable. The power supply in my "gaming" computer is 1200W, the fan runs at MAYBE 1000rpm, 92% efficient, and has a < 1% regulation and <25mv ripple.
                  It is a mistake to think you can solve any major problems just with potatoes.


                    OK, problem solved. After not finding a suitable i.e., fully working, P4 power supply in my stash pile I decided to rig a non-P4 model with the P9 motherboard power cable it didn't come with that the P4 models do have. So I cut the plug off the dead one and made one of these:


                    That was easy enough and now my P4 is back in full operation.
                    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step