Image Map Image Map
Page 5 of 7 FirstFirst 1234567 LastLast
Results 41 to 50 of 64

Thread: Hello! I got a machine that was sold for parts! May need assistance?

  1. #41
    Join Date
    Sep 2008
    Location
    SE MI
    Posts
    4,725
    Blog Entries
    6

    Default

    Quote Originally Posted by Nathanieltolb331 View Post
    Right. But based on what I am seeing on the screen, it would be indicative of something not being right voltage wise. I noticed today, if I looked carefully at the screen while it was running, there was an almost imperceptible brightening and darkening of the text and Packard Bell Logo. Almost like the voltages weren't right. Also using the references that someone gave me here, I checked the power good signal, and it was within the acceptable range. 4.35V. I just can't help but wonder if there's a chip that has corrosion damage I can't see, which is 1000% likely, or that somewhere the traces got damaged that I can't see. Is it possible that the board is de-laminating? Is that the correct term? Where the layers of the PCB start to fail and separate? The failure only occurs after the board warms up a bit, which makes me think that there is a bad contact on one or more of the surface mount chips on the board. I do not have the solder tip or the soldering skills to reflow all of the pins on the surface mount chips on this board. One chip with 8 legs? Maybe I could do that. The integrated video is like a 168 pin QFP chip. I have no skill for that. I did buy another Riser card and a replacement graphics chip, if that is what was wrong. However at this point I cannot tell.
    If you have eliminated the memory and PSU, it now seems the caps are need to be scrutinized. At some point you may want to reevaluate your purchase at determine if it's worth the time and trouble. As for myself, I have a stack of mobos with bad caps.
    Surely not everyone was Kung-fu fighting

  2. #42

    Default

    The cost on the system was negligible at about 30 bucks plus about the same amount for shipping. Recapping as long as they aren't surface mount is fine. I can do that no problem. Honestly, I don't know if there are a lot of caps on the board. But I can replace those. Would failing caps cause the symptoms I am seeing?/ I only ask because I haven't really dealt with failing caps before except on my Amiga 600, and the only caps that were failing there were the audio subsystem.

  3. #43
    Join Date
    Sep 2008
    Location
    SE MI
    Posts
    4,725
    Blog Entries
    6

    Default

    Quote Originally Posted by Nathanieltolb331 View Post
    The cost on the system was negligible at about 30 bucks plus about the same amount for shipping. Recapping as long as they aren't surface mount is fine. I can do that no problem. Honestly, I don't know if there are a lot of caps on the board. But I can replace those. Would failing caps cause the symptoms I am seeing?/ I only ask because I haven't really dealt with failing caps before except on my Amiga 600, and the only caps that were failing there were the audio subsystem.
    Yes - they can be the nut of the problem. If you have a leaky cap, say one that changes its value after power-up, you can get symptoms as you are experiencing. It could very well be a sold state component - like a chip. However, I would bet on a bad cap. Also, are you confident that the video is okay?
    Surely not everyone was Kung-fu fighting

  4. #44

    Default

    Quote Originally Posted by Agent Orange View Post
    I As for myself, I have a stack of mobos with bad caps.
    That makes two of us.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  5. #45

    Default

    Quote Originally Posted by Agent Orange View Post
    Yes - they can be the nut of the problem. If you have a leaky cap, say one that changes its value after power-up, you can get symptoms as you are experiencing. It could very well be a sold state component - like a chip. However, I would bet on a bad cap. Also, are you confident that the video is okay?
    I am not confident that the video is okay. However, considering that the symptoms and issues continue regardless of whether I use on board or ISA based video I would have to guess, that even if the video is an issue, there are underlying issues that aren't resolved elsewhere. I did buy a replacement video chip, but it's I think 160 Pin QFP chip? That is far outside of my soldering abilities. In regards to the caps, there are 23 caps on the board, all electrolytic, all PTH. So as long as I document all of the values and their locations, I can replace those easily. I guess that is the next step. Asking around someone told me to use an IR thermometer to read the heat on the chips and see if one of the chips is running super hot. Strange thing is, even the 486SX-33 seems to be running fairly cooly. While the machine is actually working and not locked up, I can touch all of the chips and none of them are uncomfortable. They are a little warm but not hot. I would say they are all running at or under 45C. I don't have an IR Thermal reader, so if there are any suggestions as to where I can purchase one that won't break the bank, but will work for me, I would be appreciative of suggestions.

  6. #46

    Default

    Touch actually works quite well. If it doesn't feel hot -- it isn't.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  7. #47
    Join Date
    Sep 2008
    Location
    SE MI
    Posts
    4,725
    Blog Entries
    6

    Default

    An aerosol freeze spray is another way to go if you believe some component is running too warm. Could save you a lot of time. Example: https://www.parts-express.com/max-pr...xoCH_8QAvD_BwE
    Surely not everyone was Kung-fu fighting

  8. #48

    Default

    Thank you for the link Agent Orange. I have been meaning to get a container of that freeze spray. The next step to try at this point, will be to replace the 20-something odd caps on the board. They all appear to be 22uf/25V. I feel like I'm not looking at the right information. I know there are different types of caps but these little 22uf/25V are thin and tall, rather than short and chunky. I would like to order replacements, but as I have said, I'm very new at this. Is there a specific way to identify the type they are, shape and hole spacing and so on?

  9. #49
    Join Date
    Apr 2015
    Location
    Austin, Texas
    Posts
    1,986

    Default

    Quote Originally Posted by Agent Orange View Post
    An aerosol freeze spray is another way to go if you believe some component is running too warm. Could save you a lot of time. Example: https://www.parts-express.com/max-pr...xoCH_8QAvD_BwE
    Standard canned air dusters are cheaper, you can freeze stuff by inverting them and spraying the liquid out.

    I can buy four large cans at the local Walmart for $10

    Quote Originally Posted by Nathanieltolb331 View Post
    I feel like I'm not looking at the right information. I know there are different types of caps but these little 22uf/25V are thin and tall, rather than short and chunky. I would like to order replacements, but as I have said, I'm very new at this. Is there a specific way to identify the type they are, shape and hole spacing and so on?
    Capacitors are measured by their diameter, height and lead spacing. You can do this with a ruler, or calipers. Most capacitors come in standard sizes and have a standard lead spacing.

    22uf 25V capacitors are usually either 5x10 or 6.3x15 (the first number being the diameter and the last being height.) with a 3.5mm lead spacing.

    www.mouser.com has a good component lookup system and will ship to home addresses.

  10. #50

    Default

    I have been looking for the past couple of days for my ruler but my daughter has absconded with it. But these are tall and very thin, so I would have guess that they are the 5x10 instead of the 6.3x15 ones? In the pictures I posted earlier you can see the caps, There's a pretty clear picture of one next to the ISA riser slot on the board, where I was pointing out the battery corrosion that was on the riser slot. But they are tall and thin. That's about all I know. I'm going to have to order a new ruler from Amazon since I can't find my ruler here.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •