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IBM 5170 6mhz board won't boot.. "dead"

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    #16
    Originally posted by offensive_Jerk View Post
    It had two banks of RAM filled. I removed one bank and set the jumper to 256k setting and tried swapping the ram modules around and still didn't boot.

    I bought some extra RAM on ebay types MT1128-15 4128P and TMS41128A-15NL. Not enough to completely fill one whole bank, but I tried different combinations of new and old and still didn't boot. Unless most of the RAM chips failed, I suspect something else is hosed.
    Since it only takes one bad chip to kill the bank you really need at least one good bank of known good chips to really be able to determine anything concrete. Otherwise you might just be spinning your wheels.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

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      #17
      Originally posted by Stone View Post
      Since it only takes one bad chip to kill the bank you really need at least one good bank of known good chips to really be able to determine anything concrete. Otherwise you might just be spinning your wheels.
      Wasn't that the point of getting the Supersoft ROMS?

      Originally posted by Modem7
      Note that the Supersoft ROM diagnostics display something on-screen even if the motherboard has no RAM fitted.
      I have a Major in Post-Apocalyptic Economics.
      Wanted: Any PC-Compatible Reciprocation Dingle Arm

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        #18
        Originally posted by modem7 View Post

        If you listen long enough, is that what you hear - six of those "Two-tone" beeps followed by a single short beep? Then, the same pattern of beeps repeats over and over.
        Yes, this is what I hear. Anything else I can try? The 10mhz cpu didn't work either. I'll try a CGA card/Monitor and see what happens, but after that I'm stumped.

        I have a Major in Post-Apocalyptic Economics.
        Wanted: Any PC-Compatible Reciprocation Dingle Arm

        Comment


          #19
          I just tried the combination of the Supersoft ROMs and a clone MDA card in one of my early (and functional) 5170s, and I am hearing the 'no video card, or cannot initialise video card' beep pattern.
          I then tried an IBM CGA card and an IBM EGA card - same beep pattern.
          !!!!!
          So right now, I appear to be seeing (hearing) what you are. Of course, I am going to do some experimentation to work out what is going on.
          Last edited by modem7; January 6, 2017, 05:15 PM. Reason: Clone MDA, not IBM MDA

          Comment


            #20
            Originally posted by modem7 View Post
            I just tried the combination of the Supersoft ROMs and an IBM MDA card in one of my early (and functional) 5170s, and I am hearing the 'no video card, or cannot initialise video card' beep pattern.
            I then tried an IBM CGA card and an IBM EGA card - same beep pattern.
            !!!!!
            So right now, I appear to be seeing (hearing) what you are. Of course, I am going to do some experimentation to work out what is going on.
            I d been fooling with this thing. I can't get it to boot with the ibm chs card or a Persydtm color II. Just makes the alarm noise
            I have a Major in Post-Apocalyptic Economics.
            Wanted: Any PC-Compatible Reciprocation Dingle Arm

            Comment


              #21
              Originally posted by offensive_Jerk View Post
              I d been fooling with this thing. I can't get it to boot with the ibm chs card or a Persydtm color II. Just makes the alarm noise
              I am still experimenting, but a few times, I fell for the trap of not waiting enough time. The AT version of the Landmark ROMs takes about 20 seconds before it displays anything.

              Comment


                #22
                Background: If I am using the Landmark ROMs, it is normally the XT ones, and I do no bother with a speaker connection.

                After experimentation with the AT version of the Landmark ROMs, some preliminary results follow:


                VIDEO BEEP PATTERN

                Even on a fully functional IBM 5170 (of type 1 motherboard), using a compatible video card, I get the 'no video card, or cannot initialise video card' beep pattern. So, I am seeing a display (after the 20 second delay), and the Landmark tests run successfully to completion. It is just that for whatever reason, I am getting the misleading video beep pattern at the start. It happened for:
                * IBM CGA card
                * IBM EGA card (note: EGA works but the display is poor)
                * Clone MDA card
                * Clone CGA card

                For now, I consider this to be a bug in the AT version of the Landmark ROMs. Need to verify the above on other 5170 motherboards that I have.


                IBM MDA

                The IBM MDA card results were interesting. I have two spares, both functional (tested today). I do not hear the 'no video card, or cannot initialise video card' beep pattern. I do not see a display. Both IBM MDA cards present the same symptoms. If I then simply substitute my clone MDA card, beeps and display happen.

                Above verified on a second 5170 motherboard.

                Surprising to me was that if there was going to be a problem, I would have expected it to have been with the clone MDA card and not the IBM one.

                Presumably, some clone MDA cards (being better clones that mine) will behave the same as for the IBM MDA.

                Comment


                  #23
                  So odd...
                  That beeping totally threw me off. I thought I waited long enough, but I guess I didn't.
                  So, I got something on the screen!!!

                  It passes all the tests, then reports an error, then another error, but it doesn't tell me what.


                  ************EDIT*******
                  I just realized there is a keyboard test while reading the manual. I don't think I had the keyboard plugged in. Going to rerun the test.

                  Last edited by offensive_Jerk; January 6, 2017, 05:42 PM.
                  I have a Major in Post-Apocalyptic Economics.
                  Wanted: Any PC-Compatible Reciprocation Dingle Arm

                  Comment


                    #24
                    Ignore that first video. I ran it again with the battery plugged in. I got a LOT of errors!

                    I have a Major in Post-Apocalyptic Economics.
                    Wanted: Any PC-Compatible Reciprocation Dingle Arm

                    Comment


                      #25
                      Originally posted by offensive_Jerk View Post
                      So odd...
                      That beeping totally threw me off.
                      It certainly distracted me.

                      Originally posted by offensive_Jerk View Post
                      Ignore that first video. I ran it again with the battery plugged in.
                      Hmmm. Shouldn't need one.

                      Is that repeatable? I.e. If battery missing, PROTECTED MODE CPU stalls. If battery present, PROTECTED MODE CPU fails but tests continue.

                      Originally posted by offensive_Jerk View Post
                      I got a LOT of errors!
                      But some of those are probably understandable (e.g. no floppy controller + drive plugged in).

                      The ones always expected to pass are the PROTECTED MODE CPU test, the REAL TIME CLOCK INTERRUPT, and CMOS RAM TEST.

                      All three of those correlate nicely with the failure of the VERIFY SHUTDOWN STATUS BYTE test within the POST of the IBM BIOS ROM.

                      Supersoft test: PROTECTED MODE CPU

                      Within the MC146818 CMOS RTC chip is some RAM, and one of the RAM bytes is used to store the SHUTDOWN STATUS BYTE (shown [here]). One use of that byte is when the BIOS switches the CPU out of protected mode (done by resetting the CPU via the keyboard controller, per [here]).

                      Supersoft test: REAL TIME CLOCK INTERRUPT

                      An interrupt generated by the MC146818 CMOS RTC chip.

                      Supersoft test: CMOS RAM TEST

                      RAM within the MC146818 CMOS RTC chip.

                      IBM ROM POST test: VERIFY SHUTDOWN STATUS BYTE

                      RAM within the MC146818 CMOS RTC chip.


                      So everything is pointing to the CMOS MC146818 RTC chip, or its supporting circuitry. (partial diagram)

                      Does a very close visual inspection of the MC146818 RTC chip and the surrounding area reveal anything odd ?
                      Last edited by modem7; January 6, 2017, 06:53 PM. Reason: (Diagram) --> (partial diagram)

                      Comment


                        #26
                        Originally posted by modem7 View Post

                        Is that repeatable? I.e. If battery missing, PROTECTED MODE CPU stalls. If battery present, PROTECTED MODE CPU fails but tests continue.
                        Yes, it is repeatable. I just tested this again.

                        Originally posted by modem7 View Post
                        Does a very close visual inspection of the MC146818 RTC chip and the surrounding area reveal anything odd ?
                        Not that I can "see" visually

                        I have a Major in Post-Apocalyptic Economics.
                        Wanted: Any PC-Compatible Reciprocation Dingle Arm

                        Comment


                          #27
                          Originally posted by modem7 View Post
                          After experimentation with the AT version of the Landmark ROMs, some preliminary results follow:
                          After doing more experimentation, I have listed the results in the notes at [here].

                          Comment


                            #28
                            Originally posted by modem7 View Post
                            Does a very close visual inspection of the MC146818 RTC chip and the surrounding area reveal anything odd ?
                            Originally posted by offensive_Jerk View Post
                            Not that I can "see" visually
                            That general area sits beneath the battery, and therefore is often the first area to be affected by a leaking battery.

                            Comment


                              #29
                              Originally posted by modem7 View Post
                              Is that repeatable? I.e. If battery missing, PROTECTED MODE CPU stalls. If battery present, PROTECTED MODE CPU fails but tests continue.
                              Originally posted by offensive_Jerk View Post
                              Yes, it is repeatable. I just tested this again.
                              So,
                              Battery absent: During the PROTECTED MODE TEST, the Supersoft/Landmark ROMs restart from scratch (per your video in post #23).
                              Battery present: The PROTECTED MODE TEST completes (the test takes about 25 seconds), then the remaining tests are done.

                              I have two type 1 motherboards, and for both, the presence/absence of a battery has no effect on the output of the Supersoft/Landmark ROMs.

                              At first I thought, I know what the cause is. This will be failure of the area that I have marked as '+5V SWITCH' in the diagram at [here] - with no battery present, the CMOS/RTC circuitry is not getting power when the motherboard is powered on.

                              But I am not convinced, e.g. if the switch had failed, then with a battery present, surely the motherboard would start up normally with the IBM BIOS ROMs fitted.

                              Anyhow, the switch can be quickly ruled out. Do you have the ability to measure DC voltage? If so, remove the battery, then measure pin 24 of the MC146818P chip (U117) when the motherboard is powered on. You should measure about +5 volts.

                              Comment


                                #30
                                Originally posted by modem7 View Post
                                So,
                                Battery absent: During the PROTECTED MODE TEST, the Supersoft/Landmark ROMs restart from scratch (per your video in post #23).
                                Battery present: The PROTECTED MODE TEST completes (the test takes about 25 seconds), then the remaining tests are done.

                                I have two type 1 motherboards, and for both, the presence/absence of a battery has no effect on the output of the Supersoft/Landmark ROMs.

                                At first I thought, I know what the cause is. This will be failure of the area that I have marked as '+5V SWITCH' in the diagram at [here] - with no battery present, the CMOS/RTC circuitry is not getting power when the motherboard is powered on.

                                But I am not convinced, e.g. if the switch had failed, then with a battery present, surely the motherboard would start up normally with the IBM BIOS ROMs fitted.

                                Anyhow, the switch can be quickly ruled out. Do you have the ability to measure DC voltage? If so, remove the battery, then measure pin 24 of the MC146818P chip (U117) when the motherboard is powered on. You should measure about +5 volts.
                                I get no voltage reading off of pin 24 of U117 when the system is powered up.
                                I have a Major in Post-Apocalyptic Economics.
                                Wanted: Any PC-Compatible Reciprocation Dingle Arm

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