Image Map Image Map
Page 2 of 5 FirstFirst 12345 LastLast
Results 11 to 20 of 42

Thread: 5150 Not Passs Mem Refresh Test

  1. #11

    Default

    Quote Originally Posted by KLund1 View Post
    There is still know way to ID which individual chip(s) are causing the problem.
    I just have to find some time to alter my diagnostic ROM as proposed above. The difference in the written and read value should point to the offensive bits.

    Also the ground and + volt pins are really hard to get out without some damage to the hole and/or the board.
    I recognize the problem. In the worst case AND having enough spares of the IC, I just cut it out the board (cutting it at the top of each pin). I then only have to worry about one pin each time.

    Is there are procedures to use a logic probe to find the bad chip(s), perhaps?
    Assume the 8253 timer signals the 8237 that it is time to refresh the DRAMs but the signal never arrives for what ever reason. I doubt very much if you can see the little blip wit a probe. A logic probe? No, or you have to be very lucky.
    A oscilloscope would do better. Much better would be a logic analyzer. But the prizes are "better" as well.
    Unless you have a lot of time at hand, wait for my new ROM that will tell you why the 2 KB RAM test failed.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  2. #12

    Default

    Big bummer: I found a bug in the memory test. I already found the test quite fast and I thought that were my programming skills. Checking to find a way to output the reason why the 2 KB test halted the diagnostics, I saw that I used register DX twice: once to save the contents of CX and once as I/O register. It meant that, instead of restoring CX with its original value, it was written with this I/O value, 61h, instead. 97 or something like 2048 is a big difference. And why did I use DX in the first place? 61h can be used directly as well in an IN or OUT command.

    To make things sure: this bug could never cause the error KLund1 ran into.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  3. #13
    Join Date
    May 2006
    Location
    Melbourne, Australia
    Posts
    6,700

    Default

    Quote Originally Posted by KLund1 View Post
    The system had the 1983 BIOS upgrade. There was a HD in the computer so they need that upgrade.
    Per [here], that will be a 1982 dated upgrade (10/27/82).

    Quote Originally Posted by mikey99 View Post
    What symptoms do you observe when the board boots with the original ROM chips.
    Quote Originally Posted by KLund1 View Post
    On normal boot I get 1 long beep.
    Ruud's soon-to-be-modified diagnostic may reveal a bad RAM chip (or chips) in bank 0, however I am curious about the long beep you are hearing from the 10/27/82 BIOS.

    The breakdown of the POST in the 10/27/82 BIOS is at [here]. The only single beep is at step 27, and that is a short beep, not a long one.

    And, if there is indeed bad RAM in bank 0 (16KB sized on the 16KB-64KB motherboard), the POST would halt the CPU at step 13, which is before any of the steps that issue any beeps.

    So, puzzling.
    How long, in seconds, is "long" ?

  4. #14
    Join Date
    Jun 2012
    Location
    Livermore, CA
    Posts
    378

    Default

    Ruud,
    Thanks for the input. I am glad to be of help. Let me know when the new ROM code is ready and I will burn an eprom, and test on this board. For me, finding the issue with the 1st 16K has been difficult on many boards. Some I have yet to solve. Those boards are gathering dust, awaiting a fix so a new user can appropriate them.

    modem7. I as gong from memory on the beep. I will reconfigure to original chip set and report back with accurate data.

    As always, I very much appreciate all your help in my learning process with these vintage machines!!
    Atari Falcon030, Atari MSTE, Atari PS3000, STACY 4, 4160STE-CosmosEX, Atari PC1, 400/800/1200XL,800XL,800XE,130XE, XEGS, Apple IIGS, TRS-80 4P, TI 99/4A, Co-Co 3, Amiga 500, C64/128D

  5. #15
    Join Date
    Jun 2012
    Location
    Livermore, CA
    Posts
    378

    Default

    Hi, all I am back to the board again.
    I put the original ROM back in and tested. I get no beep at all on power up. I must have been thinking of another machine, sorry.
    I tried another speaker to verify, and get nothing. I do get a small click when I power it down.
    I do get the same screens from RUUD's and Supersoft ROM's.
    I forgot I have an ISA/PCI PC Analyzer card like this:
    https://www.amazon.com/4-Digit-Displ.../dp/B00RX56KWC
    I only get red LED's from 3.3+v and 12+V. I do not think that is right. AS mentioned above I did have to replace several caps near the Mem chips to get it to boot. Maybe there are others I should replace. if so, which?
    Suggestions.
    Thanks
    Atari Falcon030, Atari MSTE, Atari PS3000, STACY 4, 4160STE-CosmosEX, Atari PC1, 400/800/1200XL,800XL,800XE,130XE, XEGS, Apple IIGS, TRS-80 4P, TI 99/4A, Co-Co 3, Amiga 500, C64/128D

  6. #16
    Join Date
    May 2006
    Location
    Melbourne, Australia
    Posts
    6,700

    Default

    Quote Originally Posted by KLund1 View Post
    I forgot I have an ISA/PCI PC Analyzer card like this:
    https://www.amazon.com/4-Digit-Displ.../dp/B00RX56KWC
    I only get red LED's from 3.3+v and 12+V. I do not think that is right.
    That card is detailed at [here]. The +3.3V LED is monitoring the -5V contact in the ISA slot. Therefore, expected to be lit, are all four voltage LED's.

    You must have +5V present, otherwise the Supersoft diagnostics and Ruud's diagnostics would not be executing.

    BTW. Do not expect any diagnostic codes to display when that particular model card is plugged into an IBM 5150, even if you know for fact that a diagnostic ROM outputs codes. Vintage POST cards are a different story.

  7. #17
    Join Date
    May 2006
    Location
    Melbourne, Australia
    Posts
    6,700

    Default

    Quote Originally Posted by KLund1 View Post
    I do get the same screens from RUUD's and Supersoft ROM's.
    The Supersoft ROM screen shot at post #8 shows failure of the MEMORY REFRESH test (specifically bits 6 and 3).
    At [here] is an example of the MEMORY REFRESH test failing because of a bad RAM chip in bank 0.
    Bad RAM chips in your bank 0 ????

  8. #18
    Join Date
    Jun 2012
    Location
    Livermore, CA
    Posts
    378

    Default

    Many thanks for the posts.
    So I replaced bits 3 and 6, chips U41 & U44. I did my best to not damage the MB. I had to clip a few pins that did not want to let loose. I have a vacuum solder remover. But that could not help with the suborn pins. Is there some trick to getting these to just fall out of the board like the many videos I have watched to try and learn how to remove them without damaging the MB?
    I them put a bit of flux on the holes from the back,and put in a socket. I them soldered the pins in. I did a bit of clean up with ISO. I picked 2 random chips from those I pulled from the MB sockets a couple weeks ago.
    I powered it up with SuperSoft and now bits 1-7 , not zero are showing as bad. I know this test is not 100% on the first 16K, but did I damage the board with all the heat I had to use to get those stubborn pins out? Or do I need to just proceed the removing chips and testing until I can pas the test?
    Also I do not know 100% if the pulled ram chips are good. I looked online for a cheap 4116/4164 ram tester and there dose seem to be such a unit available. How do I test chips to see if they are good?
    Thanks
    Atari Falcon030, Atari MSTE, Atari PS3000, STACY 4, 4160STE-CosmosEX, Atari PC1, 400/800/1200XL,800XL,800XE,130XE, XEGS, Apple IIGS, TRS-80 4P, TI 99/4A, Co-Co 3, Amiga 500, C64/128D

  9. #19
    Join Date
    May 2006
    Location
    Melbourne, Australia
    Posts
    6,700

    Default

    Quote Originally Posted by KLund1 View Post
    I powered it up with SuperSoft and now bits 1-7 , not zero are showing as bad. I know this test is not 100% on the first 16K, but did I damage the board ...
    With the banks of RAM, a lot of signals jump from one RAM chip to the next, to the next, ...

    An open trace would explain the change in symptom - see [here].

    The circuit diagram will show which pins across the bank 0 chips are meant to be joined. Use a multimeter to see if those joined pins are no longer joined.

    Quote Originally Posted by KLund1 View Post
    How do I test chips to see if they are good?
    I see if they work in a functional motherboard.

  10. #20
    Join Date
    Jun 2012
    Location
    Livermore, CA
    Posts
    378

    Default

    Thanks Model7 !!
    your link helps.
    I checked the continuity from U3 to U45 in bank 0. All looks good. Not every pin shows 0.0 on my meter, (.LO = no continuity on my meter). Some have numbers that change. But I think that might be the circuit? Pins 2 and 15 show .LO, but the same shows on banks 1,2,& 3.
    What should SUperSoft display if 1 or more ram chips in bank 0 are missing?
    Atari Falcon030, Atari MSTE, Atari PS3000, STACY 4, 4160STE-CosmosEX, Atari PC1, 400/800/1200XL,800XL,800XE,130XE, XEGS, Apple IIGS, TRS-80 4P, TI 99/4A, Co-Co 3, Amiga 500, C64/128D

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
  •