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Thread: 5150 Not Passs Mem Refresh Test

  1. #1
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    Default 5150 Not Passs Mem Refresh Test

    I have a 5150 16K-64K board that dose not pass the SUperSoft Mem refresh test. All banks of ram were populated for the test.
    I reflowed the 8253 and got the same results.
    I then pulled all the socketed ram leaving just the solder 16K. Now SuperSoft reports critical ram area failure on all bits.
    Does this suggest that the 8283 is bad? Or 8237?
    Before this, I had to replace several caps on the -12 line to get the board to boot.
    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

  2. #2
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    There are some specific notes about SuperSoft and the 16-64KB motherboard on modem7's site:

    http://www.minuszerodegrees.net/supe.../16KB-64KB.htm

    What symptoms do you observe when the board boots with the original ROM chips.

  3. #3
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    Thanks mikey99, I was already familiar with those issues.
    On normal boot I get 1 long beep. This, I think, means something with 8253, or the 8237.
    With critical ram test passed with all ram installed, I'm not quite sure where I should look next.
    OH, thanks for the quick reply, much appreciated.
    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

  4. #4
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    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.
    Which of the three possible IBM BIOS' do you have on your 16KB-64KB motherboard ?

    What does Ruud's diagnostic ROM (found [here]) report ?
    Last edited by modem7; July 7th, 2019 at 12:44 AM. Reason: Added link

  5. #5
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    The system had the 1983 BIOS upgrade. There was a HD in the computer so they need that upgrade.
    I do not know what size eprom to use with Ruud's ROM. I have wanted to try it. I have a lot of eproms to use in many sizes.
    Thanks for the reply!
    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. #6
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    I just took a guess on a Eprom for Ruuds diagnostics and it programmed and boots on the 5150 MB !!
    I get 8253 timer channel pass 0,1,2, 8237A DMA Controller pass. 8255 Parity check pass
    Then " Check First 2K of Ram" Critical error stop....
    I did the piggyback on all 8 chips with probably good 16K chips I pulled from the other ram sockets on this board and get no change.
    Which IC is the 1st 2K chip?
    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

  7. #7

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    Quote Originally Posted by KLund1 View Post
    I did the piggyback on all 8 chips with probably good 16K chips I pulled from the other ram sockets on this board and get no change.
    What about the parity chip, #9?

    'Probably good' means you 'could' be wasting your time.

    Quote Originally Posted by KLund1 View Post
    Which IC is the 1st 2K chip?
    Unless you specify which bit is in question you can't tell which chip it is.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  8. #8
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    Well Stone, I have about 100 16K, 100 64k, 100 256K chips but I do not know if they are all working. I do not know of a quick cheap easy way to test them all. The same when you buy 'new'. No way to know for sure if they are good. I assume all are good until proven otherwise. With Atari 8-bit's, it is repetitively easy. If the ram chip gets hot quick on power up, it is bad. Not so on 5150-70's.
    Ruud's diagnostics does not show which chip is bad. Supersoft also is unreliable for the 1st 16K.
    I was hoping the piggyback method might show which is bad. But no joy so far.
    See pics for both diagnostics output.
    Both programs seem to contradict each other.
    Some thoughts on what might be wrong here?
    Thanks
    Attached Images Attached Images
    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. #9

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    Quote Originally Posted by KLund1 View Post
    I get 8253 timer channel pass 0,1,2, 8237A DMA Controller pass. 8255 Parity check pass
    Then " Check First 2K of Ram" Critical error stop....
    My BIOS tests counters and registers that can be written and then be read again. That the individual test went OK is not a guarantee that the refresh as a whole works fine. A damaged gate between two of the ICs is all what is needed to create havoc.

    The 2 KB test test the first 2 KB of RAM. In this case it isn't a single chip but the first 2 Kbit of every chip in the first row. I test it by writing various values to it and reading them again. But the reading is done after waiting some time. If the reading goes wrong it simply means that the wrong value has been read. The wrong value can be caused by one or more bad DRAM ICs or a bad refresh (no contradiction in this case). Maybe I should extend the test with showing what the written and read value were.

    About piggybacking: just don't do it. It is indeed quick but also dirty, very dirty. If a gate is broken, it can be so broken that a good one on top of it won't help. And it con be so good broken that it destroys the good one as well. Just take some time, remove the original IC and replace it with a scocket.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  10. #10
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    Ruud, Thanks for the reply. Your diagnostics are a great effort.
    This my 3rd 5150 with similar issues with the first 16K. There is still know way to ID which individual chip(s) are causing the problem.
    That is a a lot of chips to pull and put sockets in for. Also the ground and + volt pins are really hard to get out without some damage to the hole and/or the board.
    Is there are procedures to use a logic probe to find the bad chip(s), perhaps?
    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

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