From: malcor@ozemail.com.au (Ruben Panossian) Subject: Trog conversion (long post) Date: 1997/06/19 Newsgroups: rec.games.video.arcade.collecting I know it has been a while, however, here is a neater version of this easy conversion. Sorry I took so long, for those who asked me for it. Trog Multigame Conversion ------------------------- The following conversion enables Trog Part 1 and Part 2 to be played from the one PCB, selectable via a DIP switch setting. The conversion involves replacing four of the game EPROMs with modified ones. These ROMs will contain the two different versions of the different program and graphics ROMs. The CMOS SRAM is also replaced with a larger one, otherwise the game will display a 'CMOS Invalid Error' when changing between game versions. Leaving the original SRAM installed will result in all of the game settings and high scores being reset to default when changing between game versions. There are no tracks to cut(* see text) and the modifications are transparent to the game, when the original EPROMs and SRAM are re-installed. Over all the conversion is very simple and requires little time and effort to complete. Materials you will need: 4 x 27C020 <150ns EPROMs 1 x Low power 256K static RAM, HY62256ALP or similar 200mm of hook-up or wire wrap wire. Note: make sure the SRAM is of the low power type, otherwise the backup battery will fail in a short period of time. Zeropower SRAM's, like a MK48Z30, are also OK to use. Although they are more expensive as they have their own battery. Procedure: ----------- Step 1: Program the four 2 meg EPROMs so that one half of the EPROMs contain one version of the program, and the other half contains the other version. Make sure that you keep all the versions on the same half of the EPROM, for all the EPROMs. Here is how the EPROMs may be programmed: U105 00000 - 1FFFF (U105, Trog Part I) 20000 - 3FFFF (U105, Trog Part II) U89 00000 - 1FFFF (U89, Trog Part I) 20000 - 3FFFF (U89, Trog Part II) U113 00000 - 1FFFF (U113, Trog Part I) 20000 - 3FFFF (U113, Trog Part II) U97 00000 - 1FFFF (U97, Trog Part I) 20000 - 3FFFF (U97, Trog Part II) Step 2: Replace the EPROMs on the PCB with their corresponding merged EPROMs. Also replace the static RAM at location U49. Step 3: Remove the jumpers W24-W33 and W67-W68. The jumpers are zero ohm resistors. W24-W33 is located near U54. W67-W68 is located next to U89. [ note: these jumpers are not needed for the game to work, however, need to be removed in order for the conversion to work] Step 3: Connect the following pins together, with hook-up wire, on the solder side of the PCB: Dip Switch 1, switch 8 (pin closest to the edge connector) W67 solder pad (not the W68 solder pad) Pin 30 of U90 (EPROM U90) Pin 1 of U49 (SRAM) [to keep the length of wire to a minimum, use W67 as the middle point of the wire connections] * If your Trog PCB revision is earlier than REV-B, then one track will have to be cut in order for the conversion to work. The cut track will not effect the game with the original EPROMs re-installed. The revision of the PCB is found on the solder side of the PCB near U99. If there is no revision letter, (ie REV.- ) or a revision before B, then the track described below will need to be cut. The track is not present on PCB's with a B revision or revision label C-13234-4003. A C-13234-3044 labelled board has the above mentioned track. This label is usually found on or near U115. It would be a good idea to check to see if your board has the track or not, if you are not sure what revision your PCB is. Location of the track: (if present) Locate pin 32 of U90 on the solder side of the PCB. If there is a track joining pin 32 to pin 30 of U90, then you have an early revision of the PCB. The track also continues to pin 30 of U106. If there are no tracks going to either pins 30 or 32 (on the solder side of U90), then there is no need to cut any tracks. Cutting the Track: If there is a track joining pins 32 and 30 of U90, then cut the track. Do NOT also cut the continuation of the track, which goes from pin 30 of U90 to pin 30 of U106. Before powering the game re-check the four soldered connections on the PCB. Make sure that they are soldered on the correct pins and that there are no shorts to other pins. Also check to make sure that the EPROMs and SRAM are all installed correctly. Having completed the above steps, the game is ready to power-up. Switching between the two game versions is done by the position of switch 8 of DIP switch 1. It is an unused DIP switch and will not effect any of the game settings. The game can be changed while it is still powered. If the watch-dog reset does not reset the game then you will need to press the reset button, located near the JAMMA connector, or power cycle the game. As I mentioned before, the PCB modifications do NOT effect the game with the original EPROMs and SRAM re-installed. Even if you change the setting of DS1 SW8. Trouble Shooting: ----------------- Here are some tips for trouble shooting, in the unlikely event that you do have any problems. Problem - One of the four merged EPROMs go red on the power-on self test screen, for both game versions. Solution - Make sure that the EPROM is seated correctly and that none of its pins are bent. - Make sure that the EPROM is faster than 150ns. - Reprogram the EPROM. Problem - One of the four merged EPROMs go red during the power-on self test, for only one of the game versions. Solution - Verify that the Vcc on the PCB is +5V - Reprogram the EPROM. Problem - Game does not power-up. Solution - Make sure that EPROMs U89 and U105 are seated correctly. - Ensure that W67-W68 jumper has been removed. - Verify that the hook-up wire is going to the W67 pad and not to the W68 pad. - Make sure EPROMs U89 and U105 are faster than 150ns. - Verify that the Vcc voltage on the PCB is +5V. - Reprogram EPROMs U89 and or U105. Problem - Only one game version can be selected, with DS1 switch 8 in either position. Solution - Make sure that the hook-up wire is going to the correct side of the DIP switch. Problem - U113 and U97 give an error during the power-on self test for one game version only. Solution - Ensure that jumper W24-W33 has been removed. - Verify that the hook-up wire is going to pin 30 of U90. - Reprogram EPROMs U113 and U97. Problem - There is a CMOS error when changing between game versions. Solution - Verify that the SRAM (U49) is seated correctly. - Make sure that the hook-up wire is going to pin 1 of U49. - Ensure that the SRAM is of the right type and speed. - Check/replace the back-up battery. - Don't change the game during the power-on self test. - Replace the SRAM (U49). Problem - The game stops half way through the power-on self test after which the PCB erupts in flames. Disclaimer- It is not my fault! ...and put the flames out ;-) If there are any questions, suggestions or comments regarding the above conversion then feel free to contact me. Ruben Panossian (malcor@ozemail.com.au)