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Thread: IBM XT 286 5162 - 201 RAM Error / DRAM D41464C or Sprague 61Z14A075 61Z14A150 ??

  1. #1
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    Default IBM XT 286 5162 - 201 RAM Error / DRAM D41464C or Sprague 61Z14A075 61Z14A150 ??

    Hi!!
    Ok, I'm going to throw as much information as possible, because I have here a rare IBT XT 286 that refuse to boot, and just shows the following numbers:

    000000 0800 201

    BIMG_20200220_113056.jpg

    If I remove both RAM from the sockets, I got:

    000000 FFFE 201

    The motherboard number is: 62X1168 a43499 V0011. Is this model you can see here:

    BIMG_20200220_145915.jpg

    I also removed the two 16 pins D41256C-15 DRAM NEC chips, and four 18 pins D41464C-15 DRAM NEC chips. Same error.

    BIMG_20200220_121903.jpg

    I started placing the chips one by one, also moving the switch (there's no jumpers in this board), and nothing, the exact same results.

    So, after reading some information about it on a forum thread in here (thanks everyone), I just imagine that the delay line chips, or DRAM chips are not working as they should.

    In the IBM 5170, the PE21213 seems to be the only delay line chip, but here I have two SPRAGUE chips, a Sprague 61Z14A075 and a Sprague 61Z14A150.
    I can get two Sprague 61Z14A200, but I'm not sure if the delay on the pins will cause trouble. Of course, since they used a 61Z14A150 and a 61Z14A075, I assume that I can't simply replace them for two 61Z14A200 and wish for the best...

    For the moment, I couldn't find any A075 or A150, just a200, and no datasheet of them was found neither.

    So my basic questions would be: should I get 2 Sprague 61Z14A200??

    Or should I replace all DRAM NEC chips?? (x2) D41256C-15 and (x4) D41464C-15.

    Or... ??

    I hope you can give me some help. I'm not an expert at all, but I really want to have this computer back in business!!

    Thank you all in advanced.

  2. #2

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    http://minuszerodegrees.net/5162/ram/5162_ram.htm

    This might be a good start to finding the correct type of ram.

    while this can be fairly controversial, I have had good luck purchasing RAM IC's from UTsource https://mob.utsource.net/tabs/home

    I've purchased 4116, 4164, and 41256 chips from UTsource and had good luck, your mileage may very...

  3. #3
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    Quote Originally Posted by Dani G View Post
    Hi!!
    Welcome to these forums.

    Quote Originally Posted by Dani G View Post
    Ok, I'm going to throw as much information as possible, ...
    I wish more people would do that.

    Quote Originally Posted by Dani G View Post
    ... because I have here a rare IBT XT 286 that refuse to boot, and just shows the following numbers:
    000000 0800 201
    201 = RAM error
    000000 = address 000000
    0800 = error in bit 11

    (BTW. Normally, for an IBM 5162/5170, a RAM error at address 000000 does not show, unless an MDA card is being used. I presume that you have an MDA card.)

    Quote Originally Posted by Dani G View Post
    If I remove both RAM from the sockets, I got:
    000000 FFFE 201
    (Removing the two SIMM's, which are the RAM chips that start at address 000000.)

    FFFE = all (well, almost all) bits in error.

    That is expected when the two SIMM's are removed.

    From the diagram at [here], it appears that bit 3 in the SIMM fitted to your slot S2 has become faulty.
    If you swap the two SIMM's, does the error change to 000000 0008 201 (0008, not 0800) ?
    If it does, you have a faulty SIMM.

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    Thank you so much for your helpful information guys, you are the best.

    For the moment, I can confirm that, when I swap the SIMM's in SLOT 1 and 2, the ERROR number varies from "0800" to "0008". As one is faulty, I already ordered a new 256KB Mitsubishi MH25609BJ-15 SIMM. This will fix part of the problem (if not all, fingers crossed).

    On the other hand, YES, I'm using a MDA Video card, a Hercules V-112-B to be more specific.
    So, according to the 5162 MoBo specifications provided, if I can disable all DRAM chips using Jumper J10 (what I called before "switch"), the MoBo would boot with the new SIMM installed even if there's something going on in the DRAM area, right??

    Or can we directly discard faulty NEC chips in the DRAM because it all is caused by a faulty SIMM??

    Another question would be, using another non MDA video card, will allow the use of the DRAM without getting the address "000000 ... " Error?? Is the Hercules Video Card blocking the boot sequence?... (if that is true, no more Hercules for me, mama... )

    The "funny" thing is that I have a WORKING 1988 Video Seven D2A 62L1989V5 VEGA /VGA Video Card that whould definitely help me to deal with this whole thing, but I just can't make it work on the 5162 board. I've read this thread talking about how to configure it to make it work on a 5160 IBM:

    https://ibm.retropc.se/5160/vga/5160_vga.html

    It refuses to give image signal while it perfectly works on another vintage MoBo I have... weird!!

    I will wait to receive the new Mitsubishi SIMM, but this Video Card "000000" issue and getting no-signal from a working Video Seven just piss me off.

    Thanks again guys!

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    Hi!!

    I wrote a reply to gave you all thanks for your help, but seems it was lost while in transit..

    Anyway, I got a new SIMM, and yes, I confirm that one was faulty. I got the new one installed, and the Mother Board started to work and, after Boot sequence (with all RAM detected), Cassette Basic showed up (which was fantastic)

    Bad news is that The HERCULES MDA card is causing A LOT of issues, and now is not even giving any signal AT ALL, which is quite odd, because it was working OK.

    I got a VIDEO SEVEN card installed, and I know IT SHOULD WORK. I can confirm it's with the right jumper configuration, but I got nothing. No video signal AT ALL.

    At this point I'm thinking that, could the BIOS be configured to work with this Hercules MDA Video card, and that's the reason why is not accepting Video Seven Card??? (Even the Hercules is causing so much trouble)

    If the answer is YES, how should I reset the BIOS configuration??
    Should I use the EEPROM Programmer to install 2 new 27C256 EPROM chips with the correct IBM XT 286 BIOS Images on them?

    I know it shouldn't be the best way to proceed, but there's no chance to reset the BIOS configuration if the Mother Board refuses to boot... ??

    I obviously got the " 501 - CRT ERROR " message while it was working, but also randomly got:

    PARITY CHECK 1
    00000 (S)

    I'm really stuck right now, because the MDA Hercules card just gives video signal 1 time every 50 attempts, and the Video Seven is useless right now, but should wonderfully work.

    Many thanks again for all your support and helpful information.

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    Refer to [here]. When you swap about the two video cards, are you setting motherboard switch SW1 to the proper setting for the card ?

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    Quote Originally Posted by Dani G View Post
    As one is faulty, I already ordered a new 256KB Mitsubishi MH25609BJ-15 SIMM.
    Quote Originally Posted by Dani G View Post
    ... but also randomly got:
    PARITY CHECK 1
    00000 (S)
    Random RAM parity errors at address 000000.

    I guess a question is, "Is the MH25609BJ-15 a suitable replacement?"

    From the 5162's technical reference, some motherboard RAM requirements are:
    1. "Memory access time is 150 nanoseconds and the cycle time is 275 nanoseconds."
    2. "..., with parity checking."
    3. "256 refresh cycles are required every 4 milliseconds, but the system hardware refreshes every 3.84ms."

    Regarding requirement #1. The '-15' in your MH25609BJ-15 will indicate 150 ns, and so requirement #1 is met.

    Regarding requirement #2. When I search online, I see some MH25609BJ-15 with no parity chip (8 chips total), and some that do have the parity chip (9 chips total). The 5162 motherboard requires RAM with parity.

    Regarding requirement #3. A photo that I saw of the MH25609BJ-15 SIMM showed that it contains chips of M5M4256J. A datasheet of the M5M4256J shows 256 refresh cycles @ 4 milliseconds maximum. So requirement #3 is met.

    I do not own a 5162. I cannot see much online regarding replacing the SIMM's that IBM supplied. I see, "It turns out that the 256k SIMMs aren't JDEC standard, ..." Maybe someone who owns a 5162 has more information that they can supply (i.e. some owners are likely to have sought spare SIMM's in anticipation of failure).

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    Hi!! Thanks.

    Yes, I've tried Rear and Front positions with SW1, and even used the J10 Jumper to disable the 128Kb of RAM, becasue It seems that the RAM, or the amount of RAM detected, affects the boot process.

    It's weird because, when I got "the right configuration" after some struggle, and the Mother Board boots OK, I turn OFF the PSU, then turn it ON again, and I got absolutely NOTHING, not even video signal...

    While I wait to hear your wise suggestions (thanks again) I just ordered two M27C256 chips (150ns) that I will use to burn two new, and presumably faster, U34 and U35 BIOS Chips for this 5162 Mother Board. I believe it will help in some way or another.

    " Video Card - BIOS - RAM ".

    This looks like the "Bermuda Triangle" that is driving this IBM XT 286 crazy.

    BTW, did anyone succesfully used any of the available versions of Supersoft/Landmark Diagnostic ROM's on a 5162 IBM XT 286??? Is this an option that I should consider??

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    Quote Originally Posted by Dani G View Post
    The "funny" thing is that I have a WORKING 1988 Video Seven D2A 62L1989V5 VEGA /VGA Video Card that would definitely help me to deal with this whole thing, but I just can't make it work on the 5162 board.
    I have that card (mine being pictured at [here]). First, I put it into my IBM 5160, to verify that it still worked (at VGA). I then moved the card to an IBM 5170 motherboard of type 3. It worked there as well.

    My card is dated about 1988, at least a year after the 5162 was released. However, I see that the 5162 ('XT/286') is not specifically included in the advertisement shown at [here], but maybe the maker's marketing team considered the 5162 to be an XT.

    Verify that the SLOT8 jumper is in the correct position. My card would not work with my 5170 motherboard whenever I put that jumper into the position for slot 8 of an XT.

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    Quote Originally Posted by Dani G View Post
    So, according to the 5162 MoBo specifications provided, if I can disable all DRAM chips using Jumper J10 (what I called before "switch"), the MoBo would boot with the new SIMM installed even if there's something going on in the DRAM area, right??
    Or can we directly discard faulty NEC chips in the DRAM because it all is caused by a faulty SIMM??
    Your use of "DRAM" and "SIMM" is somewhat confusing. The subject SIMM's are printed circuit boards that contain DRAM chips. But I do understand that by "DRAM", you mean the chips that occupy the 512-640KB address space.

    If I had a fully functional 5162 motherboard (i.e. 640 KB of operational RAM), and I removed one of the RAM chips that occupies the 512-640KB address space, I would expect to see the POST display a 201 error that points to address 512 KB.

    For the motherboard to start and boot into Cassette BASIC, or DOS, etc., the RAM past 512 KB is not required. So, if you want, you can use the J10 jumper block to disable that RAM. Later, when the problems are fixed, you then enable that RAM.

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