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Altair 8800B T - Some Progress

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  • billdeg@aol.com
    In late 2004 I bought an Altair 8800b T with zero idea of how to use and support s-100 systems. I still have copies of the original emails sent to this group,
    Message 1 of 13 , Jun 15, 2008
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      In late 2004 I bought an Altair 8800b T with zero idea of how to use and 
      support s-100 systems.  I still have copies of the original emails sent to this 
      group, and responses.  A lot has happened since then.
      
      Long story short, with help I finally have the machine running insofar as I 
      can get to the turnmon dot prompt:
      http://www.vintagecomputer.net/MITS/8800b-t/
      (note photo dates indicate stages of progress)
      
      The most recent advance came when I removed the jumper modifications in the T 
      socket and replaced with a LS73 (per schematic).  Not sure why the original 
      owner wanted to make jumpers permanently tied to power and ground. It had a Q 
      and Q bar output.  I am not an engineer.
      
      At this point I can load and edit individual RAM bits, but when I attempt to 
      dump a block, the dump does not display in the expected matrix of octal bits.  
      The system seems to be running through the memory, but the screen display is 
      a garbled progression of ascii characters, staying on one line while printing 
      to the screen, holding on the last column of the line and printing random 
      characters, only occasionally jumping to the next line, etc. until the dump is 
      complete.
      
      From the pictures you can see that the address-by-address display is fine, 
      and for this reason I don't believe that there is a baud rate problem.  Both 
      terminal and system are 9600.  Something else is the culprit.
      http://www.vintagecomputer.net/MITS/8800b-t/8800Bt_sn_300-000234_screenshot-me
      moryedit.JPG
      
      I will keep at it.  This is a good learning experience.  Just thought I'd 
      post the progress.
      
      Bill D


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    • jack99rubin
      Bill, I can t navigate to your screen shots, but my first thought is it might be a handshaking issue, either hardware or software, if you re overruning your
      Message 2 of 13 , Jun 15, 2008
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        Bill,

        I can't navigate to your screen shots, but my first thought is it might
        be a handshaking issue, either hardware or software, if you're
        overruning your terminal. Try running at 110 or 300 baud and see if
        things clear up. Also be sure you have the correct parity and stop bit
        settings. Seems like you're pretty close.

        Jack
      • Dan Roganti
        billdeg@aol.com wrote: At this point I can load and edit individual RAM bits, but when I attempt to dump a block, the dump does not display in the expected
        Message 3 of 13 , Jun 15, 2008
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          billdeg@... wrote:
          At this point I can load and edit individual RAM bits, but when I attempt to 
          dump a block, the dump does not display in the expected matrix of octal bits.  
          The system seems to be running through the memory, but the screen display is 
          a garbled progression of ascii characters, staying on one line while printing 
          to the screen, holding on the last column of the line and printing random 
          characters, only occasionally jumping to the next line, etc. until the dump is 
          complete.
          
          >From the pictures you can see that the address-by-address display is fine, 
          and for this reason I don't believe that there is a baud rate problem.  Both 
          terminal and system are 9600.  Something else is the culprit.
          http://www.vintagec omputer.net/ MITS/8800b- t/8800Bt_ sn_300-000234_ screenshot- me
          moryedit.JPG
          
          I
          .

           

          Bill,

          I only see the screenshot of the good display output and not the bad one.

          It could be something having to do with the monitor software having a different format to dump a block of memory versus a single address. I really don't think it's a baudrate issue. I've see weird stuff like this before  --once you see the correct characters using other monitor commands you can be rest assured the settings on dipswitch 401 which affect the baud are fine(such as the rate, parity,duplex,etc). I see in your directory that you have the H89 terminal there. Looking at that manual you want to check the other settings on dipswitch 402 which affect the screen formatting--such as--sw3= auto LF with CR,  sw4=auto CR with LF. , sw2(wrap around), and sw5(ansi mode).
          I could be something simple ,such as, the terminal was expecting a LF but the monitor only sent a CR instead of both.

          hope that helps
          =Dan
          [ Fathers Day = no excuse to hack on vintage computers        ] 
          [ Pittsburgh --- http://www2.applegate.org/~ragooman/         ]

        • billdeg
          I am working on this, here is more detail per request. I have tried every combo of switch on the terminal, and using same terminal (Z-19) compared with other
          Message 4 of 13 , Jun 28, 2008
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            I am working on this, here is more detail per request.

            I have tried every combo of switch on the terminal, and using same
            terminal (Z-19) compared with other computer's reactions (a Cromemco)
            to changes in baud/parity/CR-LF variations/etc to be sure the terminal
            itself was OK.

            I have even cut the s0 and s1 jumpers on the PROM card to reduce the
            baud to 1200 (from 9600) with the thought that the higher speed may be
            the problem. It wasn't. Same exact issues, just slower now...

            I am going to work to confirm that PROM memory and related switches
            are mapped correctly as it has been suggested that there could be a
            conflict with these and the 32K RAM. The 32K RAM (2 16K RAM cards)
            are mapped 0-16 and 16-32 respectively. I can write and recall RAM
            from the RAM cards themselves, mapped to the first 32K.

            I am looking for some 2102 RAM to see if a RAM on the prom card is
            flakey.

            The PROM must be set to 176400 octal, and the PROM address switch to
            174000 octal.

            Current switches.
            http://vintagecomputer.net/MITS/8800b-t/8800Bt_promcard_switches.JPG


            more to come.
            Bill
          • billdeg
            I have removed the RAM, same problem. I can see the individual addresses, but when I try to dump within the range 176400 to 176777 it s garbled (which should
            Message 5 of 13 , Jun 28, 2008
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              I have removed the RAM, same problem. I can see the individual
              addresses, but when I try to dump within the range 176400 to 176777
              it's garbled (which should show the PROM MON).

              I think that I need to start over with the SIO jumpers on the PROM
              card. There may be a jumper that's set in conflict with what the
              terminal is capable of doing.

              Bill
            • Jack Rubin
              Bill, I may have missed some of the earlier steps on this, but have you verified that the PROM itself is good by dumping it from a reader or other card? Jack
              Message 6 of 13 , Jun 28, 2008
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                Message
                Bill,
                 
                I may have missed some of the earlier steps on this, but have you verified that the PROM itself is good by dumping it from a reader or other card?
                 
                Jack
                 
                -----Original Message-----
                From: altaircomputerclub@yahoogroups.com [mailto:altaircomputerclub@yahoogroups.com] On Behalf Of billdeg
                Sent: Saturday, June 28, 2008 7:45 AM
                To: altaircomputerclub@yahoogroups.com
                Subject: [Altair Computer Club] Re: Altair 8800B T - Some Progress

                I have removed the RAM, same problem. I can see the individual
                addresses, but when I try to dump within the range 176400 to 176777
                it's garbled (which should show the PROM MON).

                I think that I need to start over with the SIO jumpers on the PROM
                card. There may be a jumper that's set in conflict with what the
                terminal is capable of doing.

                Bill

                Internal Virus Database is out of date.
                Checked by AVG.
                Version: 8.0.101 / Virus Database: 270.4.1/1516 - Release Date: 6/24/2008 7:53 AM

              • Steve
                Have you tried dumping to a known good terminal? Or to your PC? Don t forget that you can use hyperterminal to turn your PC into a dumb terminal. If you re
                Message 7 of 13 , Jun 28, 2008
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                  Have you tried dumping to a known good terminal? Or to your PC?
                  Don't forget that you can use hyperterminal to turn your PC into a
                  dumb terminal. If you're using Windows, you have it
                  (Start/Programs/Accessories/Communications/Hyperterminal).

                  From what I understand of your problem, you're not getting carriage
                  returns after printing a line of code- Is that correct? If so, is
                  the Turmon's DUMP routine supposed to generate CF/LF characters at
                  all? If you were sending the dump to a punch, for example, you would
                  not want any sort of EOL characters in the middle of the data stream.

                  I don't have an Altair set up and running now, so I can't answer my
                  own question.

                  Steve

                  ===================================================


                  --- In altaircomputerclub@yahoogroups.com, "billdeg" <billdeg@...>
                  wrote:
                  >
                  > I have removed the RAM, same problem. I can see the individual
                  > addresses, but when I try to dump within the range 176400 to 176777
                  > it's garbled (which should show the PROM MON).
                  >
                  > I think that I need to start over with the SIO jumpers on the PROM
                  > card. There may be a jumper that's set in conflict with what the
                  > terminal is capable of doing.
                  >
                  > Bill
                  >
                • Tom Sanderson
                  Does anyone have an 88-TPM manual? My Turnkey Prom Monitor User s Guide is missing pages. The D command destription is missing and I m guessing D command
                  Message 8 of 13 , Jun 28, 2008
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                    Does anyone have an 88-TPM manual? My Turnkey Prom Monitor User's
                    Guide is missing pages. The D command destription is missing and I'm
                    guessing D command output is not meant to be displayed on a terminal.

                    Tom


                    --- In altaircomputerclub@yahoogroups.com, "Steve" <alltare@...>
                    wrote:
                    >
                    > Have you tried dumping to a known good terminal? Or to your PC?
                    > Don't forget that you can use hyperterminal to turn your PC into a
                    > dumb terminal. If you're using Windows, you have it
                    > (Start/Programs/Accessories/Communications/Hyperterminal).
                    >
                    > From what I understand of your problem, you're not getting carriage
                    > returns after printing a line of code- Is that correct? If so, is
                    > the Turmon's DUMP routine supposed to generate CF/LF characters at
                    > all? If you were sending the dump to a punch, for example, you
                    would
                    > not want any sort of EOL characters in the middle of the data
                    stream.
                    >
                    > I don't have an Altair set up and running now, so I can't answer my
                    > own question.
                    >
                    > Steve
                    >
                    > ===================================================
                    >
                    >
                    > --- In altaircomputerclub@yahoogroups.com, "billdeg" <billdeg@>
                    > wrote:
                    > >
                    > > I have removed the RAM, same problem. I can see the individual
                    > > addresses, but when I try to dump within the range 176400 to
                    176777
                    > > it's garbled (which should show the PROM MON).
                    > >
                    > > I think that I need to start over with the SIO jumpers on the PROM
                    > > card. There may be a jumper that's set in conflict with what the
                    > > terminal is capable of doing.
                    > >
                    > > Bill
                    > >
                    >
                  • Tom Sanderson
                    I m still looking for a 88-TPM manual, but found the Prom Monitor Commands ind the Attache manual. The D command punches a leader of 60 octal 302 s followed
                    Message 9 of 13 , Jun 28, 2008
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                      I'm still looking for a 88-TPM manual, but found the Prom Monitor
                      Commands ind the Attache' manual.

                      The D command punches a leader of 60 octal 302's followed by 60 nulls
                      (zero bytes). It then punches out the contents of memory in the range
                      specified in the binary Absolute Load Tape format...
                      Upon completion of the dump, the D function performs a carriage
                      return and line feed and then returns to the monitor.

                      The D command output might be readable if memory contains to code for
                      printable characters, but unprintable charcters may be interpreted as
                      controll data for the terminal or display a substitute displayable
                      character.

                      I tried dumping the monitor with an ADM-3a and HyperTerminal with
                      ANSI and VT100 emulation. I got three different garbage displays. The
                      terminal beeps when the value for the Bell is found in memory. The
                      PC2000 would probably display a tiny "bel" in the character space. If
                      memory contains the value for escape, the terminal may expect control
                      information to follow and get confused.

                      Tom




                      --- In altaircomputerclub@yahoogroups.com, "Tom Sanderson"
                      <yahoo@...> wrote:
                      >
                      > Does anyone have an 88-TPM manual? My Turnkey Prom Monitor User's
                      > Guide is missing pages. The D command destription is missing and
                      I'm
                      > guessing D command output is not meant to be displayed on a
                      terminal.
                      >
                      > Tom
                      >
                      >
                      > --- In altaircomputerclub@yahoogroups.com, "Steve" <alltare@>
                      > wrote:
                      > >
                      > > Have you tried dumping to a known good terminal? Or to your PC?
                      > > Don't forget that you can use hyperterminal to turn your PC into
                      a
                      > > dumb terminal. If you're using Windows, you have it
                      > > (Start/Programs/Accessories/Communications/Hyperterminal).
                      > >
                      > > From what I understand of your problem, you're not getting
                      carriage
                      > > returns after printing a line of code- Is that correct? If so,
                      is
                      > > the Turmon's DUMP routine supposed to generate CF/LF characters
                      at
                      > > all? If you were sending the dump to a punch, for example, you
                      > would
                      > > not want any sort of EOL characters in the middle of the data
                      > stream.
                      > >
                      > > I don't have an Altair set up and running now, so I can't answer
                      my
                      > > own question.
                      > >
                      > > Steve
                      > >
                      > > ===================================================
                      > >
                      > >
                      > > --- In altaircomputerclub@yahoogroups.com, "billdeg" <billdeg@>
                      > > wrote:
                      > > >
                      > > > I have removed the RAM, same problem. I can see the individual
                      > > > addresses, but when I try to dump within the range 176400 to
                      > 176777
                      > > > it's garbled (which should show the PROM MON).
                      > > >
                      > > > I think that I need to start over with the SIO jumpers on the
                      PROM
                      > > > card. There may be a jumper that's set in conflict with what
                      the
                      > > > terminal is capable of doing.
                      > > >
                      > > > Bill
                      > > >
                      > >
                      >
                    • billdeg
                      ... That s exactly what I am getting - garbled but consistent - that vary when I try variations of terminal settings. I assumed that one would get useful
                      Message 10 of 13 , Jun 28, 2008
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                        --- In altaircomputerclub@yahoogroups.com, "Tom Sanderson" <yahoo@...>
                        wrote:
                        >
                        > I'm still looking for a 88-TPM manual, but found the Prom Monitor
                        > Commands ind the Attache' manual.
                        >
                        > The D command punches a leader of 60 octal 302's followed by 60 nulls
                        > (zero bytes). It then punches out the contents of memory in the range
                        > specified in the binary Absolute Load Tape format...
                        > Upon completion of the dump, the D function performs a carriage
                        > return and line feed and then returns to the monitor.
                        >
                        > The D command output might be readable if memory contains to code for
                        > printable characters, but unprintable charcters may be interpreted as
                        > controll data for the terminal or display a substitute displayable
                        > character.
                        >
                        > I tried dumping the monitor with an ADM-3a and HyperTerminal with
                        > ANSI and VT100 emulation. I got three different garbage displays. The
                        > terminal beeps when the value for the Bell is found in memory. The
                        > PC2000 would probably display a tiny "bel" in the character space. If
                        > memory contains the value for escape, the terminal may expect control
                        > information to follow and get confused.
                        >
                        > Tom
                        >

                        That's exactly what I am getting - garbled but consistent - that vary
                        when I try variations of terminal settings. I assumed that one would
                        get useful display terminal output like the 680b monitor. I even read
                        the same passage from my guide, but I for some reason thought it was
                        referring to the teletype only. Now that I have re-read I agree there
                        is no differentiation.

                        From page 5 of the 88-TPM PROM Monitor User's Guide:

                        "Once the D function has received valid starting and ending addresses,
                        it punches a leader of 60 octal 302's followed by 60 nuls (zero
                        bytes). It then punches out the contents of memory starting at the
                        first address up to and including the end address in the Altair 8800b
                        binary Absolute Load Tape format, as shown in Table A. (The word
                        "punch" is used here to refer to the output of the D command, no
                        matter what output device is actually used.) If the number of bytes
                        to be punched is greater than 377 octal, the D function punches as
                        many blocks of 377 octal bytes as necessary until the number of bytes
                        left to punch is less than 377 octal bytes. The last block punched
                        may have less than 377 octal bytes. If the number of bytes to be
                        punched in the last block is equal to zero, a zero block is not
                        punched. Upon completion of the dump, the D function performs a
                        carriage return and line feed and then returns to the Monitor."

                        What I could do is move forward, assume that the system is ok and try
                        to load BASIC from cassette or papertape, or try a different PROM monitor.

                        Thanks.

                        Bill
                      • Craig Landrum
                        ... FYI, some terminals (such as Wyse) have a monitor mode where you can tell the terminal to display the hex of each character received rather than
                        Message 11 of 13 , Jun 30, 2008
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                          >
                          >I tried dumping the monitor with an ADM-3a and HyperTerminal with
                          >ANSI and VT100 emulation. I got three different garbage displays. The
                          >terminal beeps when the value for the Bell is found in memory. The
                          >PC2000 would probably display a tiny "bel" in the character space. If
                          >memory contains the value for escape, the terminal may expect control
                          >information to follow and get confused.
                          >

                          FYI, some terminals (such as Wyse) have a "monitor" mode where you
                          can tell the terminal to display the hex of each character received
                          rather than interpret it. IF you are trying to dump a prom, that is
                          what you need - or a PC program that can do the same thing.
                        • alltare
                          I m pretty sure that these Terminals don t have that kind of monitor mode: LSI ADM3, ADM3A; Beehive B100, B-150; TTY ASR-33; MITS Compter, Compter II;
                          Message 12 of 13 , Jun 30, 2008
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                            I'm pretty sure that these Terminals don't have that kind of monitor mode:

                            LSI ADM3, ADM3A;
                            Beehive B100, B-150;
                            TTY ASR-33;
                            MITS Compter, Compter II;
                            Televideo 9xx;
                            Hyperterminal.

                            MITS' VLCT terminal should display in octal as dumped (octal is the native and only mode of the VLCT).

                            Steve
                            =======================================

                            --- On Mon, 6/30/08, Craig Landrum <craigl@...> wrote:
                            ...
                            > FYI, some terminals (such as Wyse) have a
                            > "monitor" mode where you
                            > can tell the terminal to display the hex of each character
                            > received
                            > rather than interpret it. IF you are trying to dump a prom,
                            > that is
                            > what you need - or a PC program that can do the same thing.
                            >
                            > ...
                          • billdeg@aol.com
                            In a message dated 6/30/2008 1:39:54 PM Eastern Daylight Time, ... interesting. ************** Gas prices getting you down? Search AOL Autos for fuel-efficient
                            Message 13 of 13 , Jun 30, 2008
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                              In a message dated 6/30/2008 1:39:54 PM Eastern Daylight Time, 
                              alltare@... writes:
                              
                              
                              > I'm pretty sure that these Terminals don't have that kind of monitor mode: > > LSI ADM3, ADM3A; > Beehive B100, B-150; > TTY ASR-33; > MITS Compter, Compter II; > Televideo 9xx; > Hyperterminal. > > MITS' VLCT terminal should display in octal as dumped (octal is the native > and only mode of the VLCT). > > Steve
                              interesting.


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