Announcement

Collapse

Forum 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.


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.)
  • 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.



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.


"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.

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

Fixing Video Cards (Compaq Portable 486)

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Fixing Video Cards (Compaq Portable 486)

    I have a Compaq Portable 486 (actually, I have quite a few compaq portables), I absolutely love, okay, that's a little strong, more like -- really, really like these machines... let's say the video card goes bad for whatever reason. Is it possible to fix it? I mean with available parts today or is there ever a time when, regardless, the card is just deemed unrepairable?

    #2
    Originally posted by raisedabar View Post
    I have a Compaq Portable 486 (actually, I have quite a few compaq portables), I absolutely love, okay, that's a little strong, more like -- really, really like these machines... let's say the video card goes bad for whatever reason. Is it possible to fix it? I mean with available parts today or is there ever a time when, regardless, the card is just deemed unrepairable?
    Yes, it's possible to fix it if you have a tub of parts and the right tools at your disposal. What with the availability of legacy video cards these days, why would you what to? I might take it on if were the the last card on earth. Don't have the time, patience, or desire anymore.
    Surely not everyone was Kung-Fu fighting

    Comment


      #3
      It is pretty tough finding the parts you need, or at least for me. So by asking that question, it gives hope as the a very possible last resort solution =)

      I am still narrowing down the culprit so to speak. My machine boots up right away straight into Windows 3.1 wavy hort. lines moving up and down the screen. It almost looks like interference or something... reminds me when I had my old CRT monitor too close to an oscillating fan and could figure out why monitor all of a sudden had these tweaking wavy lines, then I move the fan and it was gone... it is very similar to that only I do not have a fan near my computer. I took the entire computer apart thinking it might be a loose ribbon, tighten and refitted the ribbon (I forgot to clean the ribbon) and nada, still look the same. Maybe in my mind after doing all that I told myself it looked like it improve it, but it didn't. If you know of any good resources, places that known for having vintage parts, I would be much obliged... thanks in advance!

      Comment


        #4
        Originally posted by Agent Orange View Post
        Yes, it's possible to fix it if you have a tub of parts and the right tools at your disposal. What with the availability of legacy video cards these days, why would you what to? I might take it on if were the the last card on earth. Don't have the time, patience, or desire anymore.
        Do you even know what a Portable 486 is? If cards for it are so available, why not be really helpful and post a link to an available one somewhere...
        Last edited by MikeS; September 19, 2013, 07:38 AM.

        Comment


          #5
          Originally posted by raisedabar View Post
          I have a Compaq Portable 486 (actually, I have quite a few compaq portables), I absolutely love, okay, that's a little strong, more like -- really, really like these machines... let's say the video card goes bad for whatever reason. Is it possible to fix it? I mean with available parts today or is there ever a time when, regardless, the card is just deemed unrepairable?
          Most components needed for repairs are still readily available except for some specialized parts unique to a certain piece of equipment, and even those are often reverse engineered and remanufactured or emulated. The trouble is finding documentation and someone with the necessary knowledge, equipment and experience; replacement assemblies or even a spare machine for parts are always a good idea if you can find them.

          Is your problem on the internal monitor, the external, or both? Kind of sounds like it might be a power supply issue; don't suppose you have an oscilloscope or a friend with one?

          Comment


            #6
            Originally posted by MikeS View Post
            Is your problem on the internal monitor, the external, or both? Kind of sounds like it might be a power supply issue; don't suppose you have an oscilloscope or a friend with one?
            No, I do not own an oscilloscope, but it sounds like I should... can it be a handheld? Any suggestions?
            - I think I should pick one up
            - Then learn how to use it =)
            I have only tested with the internal monitor. I could not use an external monitor because its not vga... hmm, powersupply... I heard that before. Thank you. I will see if swapping that out fixes it.

            Comment


              #7
              Originally posted by MikeS View Post
              Do you even know what a Portable 486 is? If cards for it are so available, why not be really helpful and post a link to an available one somewhere...
              So, you in the business of repairing video cards - got the schematics and all? Mike, why don't you finish your nap.
              Surely not everyone was Kung-Fu fighting

              Comment


                #8
                Originally posted by raisedabar View Post
                I have only tested with the internal monitor. I could not use an external monitor because its not vga... hmm, powersupply... I heard that before. Thank you. I will see if swapping that out fixes it.
                It sounds as if you have the monochrome display 486, but you can still hook up a VGA monitor (at least according to the manual).

                That aside, the wavy bar thing sounds almost like what's called "hum bars", caused by AC getting into the power supply outputs. Perhaps recapping the PSU is all that's required.

                Comment


                  #9
                  Hi all, thanks for all your assistance. I really do appreciate every comment because I am new to the vintage computer world. I just think its so cool that I can now own the computers I dreamed of owning when I was young but
                  couldn't, albeit a little needed tinkering, but that's the fun part right.

                  Originally posted by Chuck(G) View Post
                  That aside, the wavy bar thing sounds almost like what's called "hum bars", caused by AC getting into the power supply outputs. Perhaps recapping the PSU is all that's required.
                  So if I had an oscilloscope I could test the capacitors in the power supply to see if they are good or not... Is that how it works. If so, very cool... that seems like it would save me some trial and error.

                  Originally posted by Chuck(G) View Post
                  It sounds as if you have the monochrome display 486, but you can still hook up a VGA monitor (at least according to the manual).
                  Yes, this is for my mono 486 (I have both, 486/c and 486 mono) but on my video card the connector is missing a hole, its made that way so when I to plug my vga connector to it, it can not because there are more pins on the vga connector than the video card connector <= phew, that's long winded... that's what happens when you are not familiar with the terminology =)

                  Thanks again Agent Orange, MikeS and Chuck(G) for taking the time and helping a newbie =)

                  Comment


                    #10
                    Well, I suppose a 'scope might tell you which power supply line needed attention, but the simples thing to try is to replace all capacitors in the power supply that are 470 uF or larger. Electrolytic capacitors eventually dry out (especially when they're run in a hot environment) and need to be replaced. Not a designed-in failure mode; just The Way Things Are.

                    Comment


                      #11
                      Originally posted by Chuck(G) View Post
                      Well, I suppose a 'scope might tell you which power supply line needed attention, but the simples thing to try is to replace all capacitors in the power supply that are 470 uF or larger. Electrolytic capacitors eventually dry out (especially when they're run in a hot environment) and need to be replaced. Not a designed-in failure mode; just The Way Things Are.
                      Okay Chuck... I like simple. I will pull out the PSU and have a looksie... I could just buy these 470 uF capacitors at any electronics store, they are pretty standard, no need for the vintage stuff? Thanks for pointing me in the right direction.

                      Comment


                        #12
                        Note that I said "470 uF and above", so that would include things like 1000 uF, 2200 uF, etc. I tend to use eBay for the stuff--I'm in no hurry and I usually get shipments from China in about a week. That suits me. There are some good guides on what to do and what not to do on the web when re-capping.

                        You might think about pulling the PSU from your 486C, if it's the same, just to see if the problem goes away when you swap it in. That would certainly confirm that what you're looking at is a capacitor issue.

                        Comment


                          #13
                          Originally posted by Chuck(G) View Post
                          You might think about pulling the PSU from your 486C, if it's the same, just to see if the problem goes away when you swap it in. That would certainly confirm that what you're looking at is a capacitor issue.
                          That exactly what I was going to do... I am checking to see if they are the same before I swap... less I make things worst =)

                          Comment


                            #14
                            Okay, I did not get a chance to check the PSU... got sidetrack with another computer the logic board for one of my macs came in and I had to do that first =)

                            This weekend for sure...

                            UPDATE:
                            Yea, just got the word that my new purchase will be sent out next week, so I will have yet another color 486... gotta have backups. So I really got to learn this recapping so I can prolong my toys... I was almost going to post a resource for a company that had new PSU in stock, I thought I hit the jackpot, and maybe they had all the overstock... then they called back and said its unavailable... they got my hopes up... I guess I was being naive because after what you said Chuck... just sitting on the shelf, even though they are new they would go bad after 20+ years... the only sure way is to know how to fix them yourself... which leads to my next post...
                            Last edited by raisedabar; September 20, 2013, 05:54 PM.

                            Comment


                              #15
                              I have another question related to above but will create a new POST instead...

                              Comment

                              Working...
                              X