Announcement

Collapse
No announcement yet.

A500 (r6a) 1MB CHIP RAM Modification: Caution dialup users: excessive H/W pr0n!

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • A500 (r6a) 1MB CHIP RAM Modification: Caution dialup users: excessive H/W pr0n!

    Hello there my fellow AmiBayers

    Recently I put up for sale a 512KB A500 Upgrade -

    If plugged into a Basic A500+ it adds it to the CHIP ram (giving 1.5MB CHIP), however if plugged into a basic A500 it would add the 512KB as OTHER ram, thus leaving the precious CHIP ram at 512KB =(

    Well we cannot have this so here is a modification that you can do at home with just a craft knife, two track cuts and a soldering iron.


    Skills Required

    1. Ability to handle a *sharp* craft knife
    2. Basic multi-meter use *continuity mode*
    3. Ability to solder one point


    First Notice

    This (HOW TO) is based on a Rev6a A500 motherboard, with an 8372a Agnus, If I find an older board I will do a how-to as well.

    Second Notice

    If you perform these alterations it is on your OWN ONUS; that means if kill the A500, you hurt yourself or others,or blow-up the street its YOUR FAULT, you do this on your OWN responsiblity


    This disclaimer includes but is not limmited by you wanting or having the urge to sing anything by "Barbra Streisand", "Wham" or "Miami Sound Machine" has NOTHING to do with me.



    Now, with that in mind we can begin =)
    Flux Mastah' Zee
    50 L337 1'M W1R3FR4M3

  • #2
    [update]

    Sadly the sever housing these images no longer exists, as such some images have been lost.


    Overview of the Mod



    With Jumper location JP2 (cut and soldered)



    with Jumper location JP7A (trace cut)
    Last edited by Zetr0; 13 August 2012, 15:27.
    Flux Mastah' Zee
    50 L337 1'M W1R3FR4M3

    Comment


    • #3
      Before the Modifcation


      heres JP7A (click to enlarge)


      Heres what Workbench says (click to enlarge)



      Need to get a *before* shot of JP2.... I forgot.... wheres that time machine got to?... i know its around here somewhere...
      Flux Mastah' Zee
      50 L337 1'M W1R3FR4M3

      Comment


      • #4
        Modding Time


        JP2 CUT



        JP7A CUT



        JP2 SOLDER
        Flux Mastah' Zee
        50 L337 1'M W1R3FR4M3

        Comment


        • #5
          After Modification


          As they say on most cooking programs - is should look like this =D


          JP2 (click for larger images)



          JP7A (click for larger images)
          Flux Mastah' Zee
          50 L337 1'M W1R3FR4M3

          Comment


          • #6
            Testing the Modification


            JP2 - Cut (testing disconnection of pad 2 and 3)



            JP2 - Solder (testing connection of pad 1 and 2) *click to enlarge*



            JP7A - Cut (Testing disconnection of pad 2 and 3
            Flux Mastah' Zee
            50 L337 1'M W1R3FR4M3

            Comment


            • #7
              Making it Happen


              So finally -

              we have cut two traces and soldered two pads together -
              we have also tested (continuity) to make sure our work is sound -

              Whats next?

              Turning it ON!!!!



              Heres the Lashup - A500 with A501 and A500HC+ (8MB RAM)

              (going to point out that the SCSI controller is connected to a SCSI->IDE adapter with a WinUAE formatted and prepped (OS3.1) on a 4.1GB HDD)



              And there is LIFE!




              Whats Workbench Say? (tell me tell me TELL ME!!!!) *click to enlarge*




              And there you have it, this took no more than 25 minutes to do AND I was taking pictures... this shouldn't take anyore more than 15 minutes in thier own home... just remember if in doubt ask before blowing somthing up.
              Flux Mastah' Zee
              50 L337 1'M W1R3FR4M3

              Comment


              • #8
                dont have the ram cards yet can i pay any of you to do this for me ?
                I will be geting two a500 in march also need 3.1 roms in them

                Comment


                • #9
                  Originally posted by keropi
                  this thread will be awesome to the max
                  Thanks my friend, this was a quick one -

                  Its important to note that IF one wanted to, you could populate the empty memory spaces at the bottom of the motherboard

                  [I]

                  if you notice in the above picture, at the bottom of the board is the chip-memory - you will also notice that there are 4 unpopulated spaces -

                  With this mod - you can poluate those spaces with 4 20 pin 256x4 DIP memory modules - Thus rendering the trapdoor interface - for the most part - redundant.
                  Flux Mastah' Zee
                  50 L337 1'M W1R3FR4M3

                  Comment


                  • #10
                    Nice Tute chap,
                    I think anyone should be able to give that a go.

                    Comment


                    • #11
                      Excellent tutorial, my friend!

                      I'm still looking for some spare time to dig a go on turning the trapdoor expansion into FAST RAM and using the spare spaces on the mobo to expand the chip RAM.

                      An humble A500 with 1Mb Chip & 0.5Mb (not so) FAST is a lovely machine on its own.
                      David Bradley made Ctrl+Alt+Del, Gates turn it mandatory
                      16 Amigas at home
                      3x C= 64
                      1 VIC-20
                      8 PC (argh) at least one is an AROS/Amithlon unit

                      Comment


                      • #12
                        this thread is awesome to the max
                        Aacheron and slk486 are my heroes
                        A1200D mfilos ed. : ACA 1231/42 , Indivision MK2 , IDEfix Express , Subway , PicoPSU 120w custom 3.9 ROM/OS

                        Comment


                        • #13
                          Originally posted by Zetr0 View Post
                          With this mod - you can poluate those spaces with 4 20 pin 256x4 DIP memory modules - Thus rendering the trapdoor interface - for the most part - redundant.
                          Just to clarify - if you solder in 44256 chips, you need to apply the same jumper mods to get 1 MB of chip? And should they be 80 ns?

                          Comment


                          • #14
                            @MagerValp

                            Yes, to solder chips in place on the motherbaord you will need to perform this modification for it to be seen as CHIP ram, you can use any 44256 20pin dip of 80ns or faster =D

                            This Mod changes the memory location of the 512KB trapdoor slot - which also linked to the 512KB sockets on the motherboard, it moves the location from (SLOW) FAST RAM (cannot remember the $address) to be inside the 1MB CHIP RAM pool
                            Flux Mastah' Zee
                            50 L337 1'M W1R3FR4M3

                            Comment


                            • #15
                              Originally posted by Zetr0 View Post
                              if you notice in the above picture, at the bottom of the board is the chip-memory - you will also notice that there are 4 unpopulated spaces -

                              With this mod - you can poluate those spaces with 4 20 pin 256x4 DIP memory modules - Thus rendering the trapdoor interface - for the most part - redundant.

                              Hmm this was raised in another thread... about adding chips to the empty space... and I dont beleive it was concluded on whether chips could be just dropped in, or if resisters, similar to the ones already on the board, were required to be added along with the additional chips... ?

                              ---------- Post added at 20:17 ---------- Previous post was at 20:15 ----------

                              Originally posted by rkauer View Post
                              Excellent tutorial, my friend!

                              I'm still looking for some spare time to dig a go on turning the trapdoor expansion into FAST RAM and using the spare spaces on the mobo to expand the chip RAM.

                              An humble A500 with 1Mb Chip & 0.5Mb (not so) FAST is a lovely machine on its own.

                              @Rkauer

                              Im confused. If adding chips to the empty motherboard memory slots along with performing this mod makes the trapdoor expansion slot redundant, how do you add the additional 0.5 mb after performing the 1mb chipram mod to total 1.5mb in an A500?
                              Amiga 1000/500/2000/3000/600/1200/4000/CD32, and a C64

                              Comment

                              Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
                              Working...
                              X