Jump to content
Have You Played Atari Today?
2600|5200|7800|Lynx|Jaguar|Forums|Store  

StickJock

Members
 View Profile  See their activity

  • Content Count

    555

  • Joined

  • Last visited

Posts posted by StickJock

  3. Posted · Edited by StickJock

    Yeah, I forgot about that, but when I first got my SIO2SD, it didn't work on my 800 either.  I found the "fixed" version of the loader somewhere online.  I don't remember at the moment what the difference was - I think the loader called some OS routine directly instead of through the vector, and as luck would have it, the routine changed addresses between the 800 OS and the XL/XE OS (and it was written for the newer OS).  I let him know about it, so I am glad that he added the fixed version to his site to help other 400/800 users.

     

     

     

  5. Posted

     

    39 minutes ago, Jayemaitch said:

    And would it matter which way its facing?

    Yes, it very much matters which way the diode is facing.  Diodes let current flow in only one direction.  You want to install it so that power can flow from the 800 to the SDMax.  This will prevent power flowing from the USB/barrel power into the Atari.  If you put it in the wrong way, it will 1) not power the SDMax from the Atari, and 2) will not protect the Atari from being backpowered.

     

  6. Posted

    The power switch is wired to either connect the SIO power or not.  It does not switch off external power.  You can still hurt yourself if you have it plugged into the Atari with a USB (or barrel power) plugged in and you move the switch to SIO.  I suppose you could put a diode on the SIO +5 line so that you don't backfeed the external power into the SIO +5 pin?

     

    • Like 1

  7. Posted

    I had a no color issue on an 800 that was caused by a bad 3086 transistor array (A104 on Atari 800 schematics).

    I don't have the XEGS schematics, but the 130XE schematics don't show this part.  They do, however, show a transistor in the Chroma video path (Q2, 2N3904).  Maybe there is an analogous part on the XEGS that has gone bad?

     

    • Like 1

  8. Posted

    When I copied my ~400 disks from the 80s to ATRs, I came across a disk labelled "Dad's WP".  It had some short stories he wrote, along with his resume.  I took a quick look at it and was surprised that he included his Social Security number on it.  Then again, my SS# was used as my student ID# at University and was on my student ID card, so I guess identity theft wasn't as big of a concern back then?

     

    If I hadn't been going through the disks one-by-one, I wouldn't have even known that was in there, and if I had ever unloaded all my 8-bit gear, I would have just included all of the boxes of disks without even looking at them.

     

    So yeah, I can see collections of disks containing some personal info, including some sensitive data.

    • Like 1

  13. Posted

    2 hours ago, ClausB said:

    Been reading up on this machine. Pretty nice for its time. Custom 4-bit CPU runs at 0.6 Mips. Up to 32KB RAM can be read 8 bits wide but written only 4 bits at a time. 42KB program ROM is 20 bits wide and implements full BASIC and I/O. Keyword atoms (tokens) save RAM space. Variables are 8-byte BCD floating point with 13 digits precision, typical for a calculator company back then.

     

    I would guess it's roughly comparable in performance to a TRS-80 Model 1 Level II. (Fun fact: the Z80 has only a 4-bit ALU inside.)

    The keyboard keys had plastic cover shells that you could remove and put new key labels under them.  It also had a toggle switch that toggled the keyboard between lowercase/uppercase & uppercase/keyword.  If you typed PRINT then it took 5 bytes, but if you used the keyword then it was only one byte.  I used all sorts of tricks to save RAM, such as renumbering the program starting at 1 with an increment of 1, no space between program line & command, stringing multiple commands on a single line with :, all keywords, single letter variable names, etc.  It was like doing a 1-line constest!

    If there was a PRINT AT or POS command, we didn't know about it, so we had to roll our own.  We started out with printing a 'home' character to put the cursor at the top-left, then used a for-next loop to print line feeds, followed by a for-next loop to print a move-cursor-right character.  I remember optimizing this to using a string containing a home character followed by 15 line feeds, and a string containing 63 "cursor right" character, and then instead of for-next loops, I would just print a subset of the string.  Much faster performance!

    The display was a 64x16 green phosphorous CRT, and the characters were tall & skinny.  There was also a pixel or two between the lines for underlines.  There was no graphics mode, so all of the games we wrote used the built-in character set.  It did have some unusual symbols, like the little "hurricane" looking one.  It probably had some international symbols, too.  I think I used 3-4 letters to approximate the buggy for my version of Moon Patrol.  I used a single character for the player & robots in Robotron.  Robotron used several files, IIRC, in order to fit in RAM.  There was a loader, the game itself, a file full of the rooms, a high score saving program, and the high score data file.

    The 2200T was the first computer that I ever used.  My older brother took me to the computer lab at the high school in the summer of 79 and taught me how to program on them in BASIC.  By the time that I got to high school, they had upgraded to a 2200VS system (minicomputer system, with a big CPU & hard drive (removable disk packs) in a small super air-conditioned room, and a dozen terminals in the lab) but they still had three of the old 2200T systems in the corner of the room, all sharing a 2-bay 8" floppy drive.  They didn't use the card reader anymore.  One was also hooked up to a 132-column daisy wheel printer.  That one also had 16K - the other two only had 8K (or was it 4K?).  Since all the classes did work on the newer systems, it was easy to get time on the old Ts, so that's where I spent most of my time.  There was also one or two Apple IIs.  Then they got a couple of dozen Atari 800s (each station had an 800, two 810s, printer & monitor - don't remember if the printer was an 825, which would have meant an 850 as well, or a 1025).  The computer classes targeted both the Wang 2200VS systems (programming in basic, cobol, fortran) and the Atari 800s (programming in basic, pascal), so the 2200Ts were nearly always available.

    Coincidentally, I was watching Cloud Atlas last night (strange movie) and saw a Wang computer in a scene at a nuclear power plant in 1978.  Prop guys were on the ball!

     

    I remember a guy a year ahead of me wrote a duplicate login screen for the 2200VS system.  He would log in, and run this program, and leave the machine.  Then, when someone would try to login, the program would save the login credentials, show a login error, and then logout.  Logging out would result in, you guessed it, a fresh login screen!  The only difference between the real & trojan screens was that he could not suppress the cursor (flashing underline) and the real login did not show the cursor.  I got in the habit of doing a fake login for my first try before entering my real credentials.  I think that he actually ended up helping out a teacher that forgot their password.  These days, he would probably get expelled at a minimum!

     

     

    • Like 2

  14. Posted

    One of my 800s had a completely dead Mitsumi keyboard.  None of the keys worked.  I fixed it by carefully peeling the membrane away from the PCB (heated it up to soften it a bit) but not where it was connected to the PCB.  Clean the PCB and let the membrane lay back down.  Put it all back together again and all of my keys worked.  Well, one of them was a bit flaky, but some banging on it brought it back to the same sensitivity as the others.  

     

    Give this a try.  It took me a while to get around to this because I was *sure* that I had a bad IC, so I waited weeks for new chips to get here from AliExpress.  After I finally ruled everything out (swapped KBs, bad KB followed the actual KB, good Stackpole KB worked on both machines), I did the above and now everything is good.

     

     

    • Like 1
    • Thanks 1

  15. Posted

    I've got one of his miniature 1050 cases.

     

    I, too, think it's cool, but i also think that the disk engage lever should be in the closed, not open, position.  How can I be reading & writing to the "disk" with the drive open? 😀

    • Like 1
    • Haha 1

  23. Posted

    On US standard 8.5" x 11" paper, it was usually either 3 holes on the left or two holes on the top.  The spacing of the 2-hole punch did not match the distance between any of the holes of the 3-hole punch.

     

    A lot of the docs that I printed out have 4 holes, since I used a 2-hole punch three times to punch a single hole on top, a single hole on the bottom, and then when punching the center hole, I got the bonus, unused 4th hole.  

    • Like 1

  25. Posted · Edited by StickJock
    Added link to calculator info

    Here is a random "joystick".  I don't remember exactly why I built this back in the mid-80s, maybe just because I could?  Or, maybe there was some game that needed precise angles?

     

    This is an old calculator that I got somewhere (maybe my dad's old calculator?), and I wired the 2-4-6-8 buttons to the four joystick wires, and the 1-3-7-8 are wired to them through diodes.  The red C button is the fire button.  The result is an 8-way control pad with a fire button.

     

    I don't remember what the PCB looked like inside.  I'm guessing that it was probably a matrix and I cut the traces to isolate the individual keys.  I don't remember doing that, but it was a *long* time ago.

     

    20200704_124327[1].jpg

     

    Here's some info on the calculator: https://americanhistory.si.edu/collections/search/object/nmah_334434

     

    • Like 3
AtariAge
Forums
Store
General
Follow AtariAge

Copyright ©1998-2021 AtariAge

×
×
  • Create New...