franco@iuvax.UUCP (02/11/86)
We got our TOS in ROM but without instructions. I don't know who else has had this problem but I suspect a number of people have or will. Therefore, I am requesting that someone with the instructions post them to the net. Thanks in advance.
rbk@akguc.UUCP (rbk) (02/14/86)
> We got our TOS in ROM but without instructions. I don't know who else > has had this problem but I suspect a number of people have or will. > Therefore, I am requesting that someone with the instructions post them to > the net. Thanks in advance. Here are the TOS ROM upgrade instructions which I received from ATARI along with my ROMS. I have attempted to reproduce the essential features of the one important Figure in the instructions. Please note that I have not verified the "BOOT EPROM Version" instructions, since I had the more common "MASKED BOOT ROM Version" which simply required replacing the two old ROMS with six new ones. I have had the ROMS installed for about two weeks now, and have encountered no real problems (I have a 1 meg ST with the "six resistors"). The only programs which I have found that don't work properly are the PD ramdisk and fontloader programs (but M-disk works fine). TOS can still be loaded from disk if desired. By the way, I checked the date of the ROM version as suggested in a previous article and got "11201985" (my disk version is dated "05291985"). Good Luck! R. Brad Kummer akguc!rbk AT&T Bell Labs Atlanta, GA ----------------------------------------------------------------------- TOS ROM UPGRADE Once plastic and shield have been removed, locate the ROM socket area of the board (left side, near cartridge slot). There are three versions of the 520ST that have been produced to date; the ROM installation will vary according to the version of the board you have, so identify your board from the descriptions below: MASKED BOOT ROM Version == This is the most common and is the easiest to upgrade. You have this version if no jumper wire is visible along the ROM socket area and the two ROM chips don't have labels on them. To upgrade, simply remove the two existing chips by wedging a small flathead screwdriver between the chip and the socket and carefully lifting up on the chips. Once the two old chips have been removed, insert the six new ROMs as shown in the figure below. Please note that it is extremely important that each ROM be put in with pin 1 on the top right corner of the chips as shown in the figure. BOOT EPROMS Versions 1&2 == These are very early computers which were produced before masked ROMS were available. You have this version if a jumper wire is visible running from below the socket marked U7 to the middle front of the socket marked U3 and/or the two chips in the sockets have labels with handwritten markings on them. To upgrade these versions requires soldering and desoldering, so if you don't feel comfortable with a soldering iron, it is strongly recommended that the upgrade be done at an authorized Atari Service Center. The first thing you will need to do, if you decide to do the upgrade yourself, is remove the PC board from its bottom plastic cover. Now turn the board upside down and look at the area underneath the ROM sockets marked U4,U5,U6,U7. Looking at pins 27 and 28 on these sockets you should be able to see a solder bridge shorting the two pins together; this short needs to be desoldered on all four sockets. Next, turn the board rightside up again and look between U3 & U4, U4 & U5, and U6 & U7; toward the right hand side between each of these sockets should be a cut trace. This trace normally connected all the pin 27's together, so you will need to jumper it back the way it was before it was cut. The easiest way is with three jumpers; first jumper pin 27 of U3 to pin 27 of U4; second, jumper pin 27 of U4 to pin 27 of U5; and third, jumper pin 27 of U6 to pin 27 of U7. Before finally plugging in the new ROMs, verify your work by checking for continuity between pin 27 of the sockets and A15, which can be found on pin 43 of the 68000 CPU chip (U10). Also make sure that all pin 27's are disconnected from all pin 28's. ---------------------------- Figure --------------------------------- _____________________________________________________ +---| | |- | |- Cartridge | |- Slot | |- | |- +---+ | ------ +-----------+ <== PIN 1 | U2 | C026160 <| +-----------------------+ | +-----------+ | CPU | | +-----------+ |_______________________| | U3 | C026161 <| | +-----------+ | +-----------+ | U4 | C026162 <| <== NOTCH | +-----------+ | +-----------+ | U5 | C026163 <| NOTE: Be sure to orient ROMS with notch | +-----------+ as shown. Lettering on ROM may | +-----------+ be inverted. | U6 | C026164 <| | +-----------+ | +-----------+ | U7 | C026165 <| | +-----------+ | ======= ======= |_________________________________________