Image Map Image Map
Page 4 of 6 FirstFirst 123456 LastLast
Results 31 to 40 of 55

Thread: 5150 motherboard no boot diagnosis

  1. #31
    Join Date
    Jan 2019
    Location
    New Hampshire
    Posts
    155

    Default

    Just a quick update:

    Here is a picture of the bad CPU socket
    DSC00433.jpg

    You'll see mostly bad pins on the 21-40 side. Pin 32 is actually broken, several others are weak and many of them have pulled up.

    The 1-20 side seems mostly intact except for a few weak wipers. This socket is coming out soon, and I'm expecting the replacement tomorrow.

  2. #32

    Default

    Quote Originally Posted by chris_nh View Post
    Just a quick update:

    Here is a picture of the bad CPU socket
    DSC00433.jpg

    You'll see mostly bad pins on the 21-40 side. Pin 32 is actually broken, several others are weak and many of them have pulled up.

    The 1-20 side seems mostly intact except for a few weak wipers. This socket is coming out soon, and I'm expecting the replacement tomorrow.
    Yeah, that whole socket is horrible. Hopefully you ordered a machine-tooled socket vs. another wiper type. You might actually have been able to get by with a couple rows of machine-tooled headers (which are often cheaper than the sockets and can be bought in multiple lengths):

    https://i.stack.imgur.com/lXhyd.jpg

  3. #33
    Join Date
    Jan 2019
    Location
    New Hampshire
    Posts
    155

    Default

    Good suggestion ... I have enough of that type on hand to do one side. I could maybe install the CPU all slanted haha. Yeah, I ordered another wiper type. It will be better than the old one at least

  4. #34
    Join Date
    Jan 2019
    Location
    New Hampshire
    Posts
    155

    Default

    Well, I did try it with the machine pins, but no change at all in the behaviour of the board, unfortunately.

    It is still intermittent as best and will not boot from a regular BIOS. It also has several intermittent states it will boot in... it either doesn't boot, or fails the timer test, or fails the rom address tests. The behaviour will even change without me touching the board, such as just now... it did a full run on landmark, then I turned it off. Did not touch the board, now it is dead again.

    I think I should expect that there is probably still a failing component somewhere in the mix. I will change the socket just to rule that out and maybe it will have an effect, but the row of machine pins has not really made any noticeable difference in behaviour.

  5. #35

    Default

    Quote Originally Posted by chris_nh View Post
    Good suggestion ... I have enough of that type on hand to do one side. I could maybe install the CPU all slanted haha. Yeah, I ordered another wiper type. It will be better than the old one at least
    It is very important if you are removing IC from sockets a number of times is that the socket pins and IC pins are lubricated (I use a small amount of WD-40 which so far I have found is safe and effective- I have no evidence of it increasing corrosion in any way on steel or brass/copper and it is an extremely good rust & corrosion inhibitor as a recent experiment confirms) it won't last beyond a 6 months or a year before it near totally evaporates , but that is initially enough for any repairs and it doesn't damage socket plastics or pcb coatings/markings).

    When there is too much friction in an IC & socket not touched for many years, in combination with corrosion between the IC pins and the socket pins, removing the IC will pull up the socket pins as you have seen. This can be prevented by the application of a little WD-40 prior to just moving the IC out of the socket a very small amount initially to break the corroded bonds between the metal surfaces and let the WD-40 infiltrate the surfaces, and you can avoid this sort of socket damage this way. It also pays to lubricate the machine pin sockets if you are planning to remove the IC's from them a number of times.

  6. #36
    Join Date
    Jan 2019
    Location
    New Hampshire
    Posts
    155

    Default

    Also just an interesting note on the ROM tests ... with ROMS installed, the tests all pass. (except U28, of course) So, I wonder if the varying ROM tests results in landmark are just due to floating pins perhaps?

  7. #37
    Join Date
    Jan 2019
    Location
    New Hampshire
    Posts
    155

    Default

    Quote Originally Posted by Hugo Holden View Post
    It is very important if you are removing IC from sockets a number of times is that the socket pins and IC pins are lubricated (I use a small amount of WD-40 which so far I have found is safe and effective- I have no evidence of it increasing corrosion in any way on steel or brass/copper and it is an extremely good rust & corrosion inhibitor as a recent experiment confirms) it won't last beyond a 6 months or a year before it near totally evaporates , but that is initially enough for any repairs and it doesn't damage socket plastics or pcb coatings/markings).

    When there is too much friction in an IC & socket not touched for many years, in combination with corrosion between the IC pins and the socket pins, removing the IC will pull up the socket pins as you have seen. This can be prevented by the application of a little WD-40 prior to just moving the IC out of the socket a very small amount initially to break the corroded bonds between the metal surfaces and let the WD-40 infiltrate the surfaces, and you can avoid this sort of socket damage this way. It also pays to lubricate the machine pin sockets if you are planning to remove the IC's from them a number of times.
    Excellent suggestion. And yes, a very correct assessment of the condition of the socket. This board was subject to corrosion from a burst battery and it had somehow got into a lot of components around the area of the expansion slots, including the cpu. I've been able to clean most of it, and I'm I sure I broke the socket when I first removed the CPU a few weeks ago to clean the board.

  8. #38
    Join Date
    Jan 2019
    Location
    New Hampshire
    Posts
    155

    Default

    Hey, I'm back... I'm really hoping maybe somebody will have some suggestions for this board (other than setting it on fire to rid the demons)

    1) The new CPU socket is installed and the board now seems to turn on normally rather than intermittently, so that's good!

    2) Diag ROM tests mostly pass, except keyboard controller and BIOS chip tests, as follows...

    2a) both diagnostics (Ruud and LM/SS) report failed keyboard controller, even with keyboard plugged in. Maybe this is it???

    2b) Ruuds diagnostic fails the ROM address tests on every pass

    2c) Landmark ROM results vary on every pass... will sometimes pass roms that aren't inserted

    3) The board will still NOT boot from a regular IBM BIOS!!! This is really puzzling me ... The BIOS runs for a little while, cursor blinks, then flashes a blip on the screen and seems to soft reset?? Does this in a never-ending loop.

    4) Ruuds ROM shows X beneath each memory bit ... is this normal?

    I'm wondering if the keyboard and bios errors are connected somehow?

    Here's another crazy idea I might try ... I have some EEPROMS on hand for my XT-IDE cards, and I have a few 27C256 EPROMS... so, if I were to burn a ROM that just did a jump to D800, I could then use the EEPROM to run diagnostics and custom tests to try and zero in on exactly whats wrong. I've been looking for an excuse to play with ASM, so this might be it.

    Anyway, if anyone has any ideas about what could be wrong with this board, please let me know what you think. Thanks!

  9. #39
    Join Date
    Jan 2019
    Location
    New Hampshire
    Posts
    155

    Default

    (I couldn't edit the post above? Perhaps there is a time limit on edits ...)

    Just to add clarity to point 2b above, Ruud's diagnostic fails with ROMS inserted

  10. #40

    Default

    Quote Originally Posted by chris_nh View Post
    (I couldn't edit the post above? Perhaps there is a time limit on edits ...)
    15 minutes
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

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
  •