- Mar 27, 2016
- Reaction score
- Northern California
By request of the forum owner, here is my project log for my Major Title 2 conversion to R-Type Leo. I am still a newbie at all of this stuff so I have written this up so that someone with my experience level or lower can follow along and perform this themselves.post some pics of your 'dark' conversion process please
This effort consists of two phases which I shall discuss over two posts:
- Rom board jumper re-configuration (surgery/soldering is required)
- Rom burning/swapping
- Major Title 2 Irem M92 board
- 3x jumper caps (.100"/2.54mm spacing)
- Optional 2x jumper caps needed for running unencrypted sound roms
- 3x Pin headers, 3 positions each (.100"/2.54mm spacing)
- Optional 2x Pin headers w/3 positions needed for running the unencrypted sound roms
- A good soldering iron with spade/flat tip
- A solder pump
- Needle nose tweezers
- Cotton swabs
- Isopropyl alcohol
- A little tape
- Minor soldering skills or some testicular fortitude
There are three jumpers that you need to reconfigure on your Major Title 2 board to prepare for the conversion to R-Type Leo. These jumpers are:
Recent efforts have decrypted the sound roms for R-Type Leo. If you choose to run the unencrypted sound rom set, you must also reconfigure the jumper settings at:
Now, these jumpers are simply wire bridges soldered into place. That works great for the longevity of this game as originally intended. But doesn't work well for us tinkerers that want to convert this game to R-Type Leo. As we work to reconfigure these jumpers, there is a consideration we have to make here. Other methods discussing this conversion around the Internet simply state to replace this wire bridges once you have moved them into the alternate jumper position. Since this forum is populated by a bunch of arcade snobs (me among them), we are going to do this a little bit cleaner. There is one more ancillary benefit for doing this which shall be discussed later. For now, here is a snap of what the wire bride looks like at J8, J15, and J16:
To remove the wire bridges, perform the following:
- Apply a small amount of liquid flux on a cotton swab and brush it over the 3 points of the J8 jumper on the components side and solder side of the rom board. This helps the solder to flow easier. Do the J8 jumper first as this one has the most clearance and is the easiest one to do.
- Place your iron on any one of the 3 points of the jumper on the component side of the board and with the solder pump extract the solder for the thru-hole point until you can see space through the solder point.
- Repeat for the two remaining solder points for that jumper.
- At this point, the solder pump should have pulled the solder from the other side of the board. If not, repeat step 2 on the solder side of the rom board.
- From the solder side of the rom board, place the flat side of your iron tip so that it touches both of the ends of the wire bridge. Apply gentle pressure as the wire bridge heats up. Do not push hard or your will bend the pins, making life harder on yourself. The idea here is that as the wire bridge heats, whatever solder is holding it in place shall melt and you will be able to push the wire bridge most of the way out. If you do this correctly, the pins will be flush with the rom board.
- Flip the board back over to the component side. Now you will have clearance under the wire bridge and will be able to use needle nose tweezers to pull the wire bridge out. If you are lucky, there is no solder holding the wire bridge fixed to the board and it will come right out. If you have any kind of resistance, DO NOT apply any force to pull out the wire bridge. Apply your iron to one point of the wire bridge and pull that side until the bridge comes free. Repeat the same for the other end of the wire bridge if needed.
- Pay particular attention as you do this, be sure not to scratch the board with your tweezers! You may cut a trace in doing so.
- Also be sure not to pull the wire bridge out if it is still soldered in place. You may pull the point along with it!
- Discard the wire bridge. You won't need them anymore.
- Apply a small amount of isopropyl alcohol to a cotton swap and clean both sides of the solder point of the flux residue.
The below photo is a blue jumper cap salvaged from a early 2000's era PC motherboard along with a row of .100"/2.54mm spaced header pins which I happened to have handy. It just so happens those salvaged jumper caps fit perfectly onto the .100 header pins! In any case, with some flush cutters, snip off 3 positions from this row of headers. You'll need three 3-position header pins as there are three jumpers we need to reconfigure.
NOTE: If you decide you want to run the unencrypted sound rom set, you will need to snip off two more 3 position headers from your header row for J1 and J6. As mentioned earlier, this is optional.
Follow the below steps to install the new jumpers:
- Dry fit the header pins into the jumper point onto the component side of the board. If you removed the wire bridges from the previous step correctly, the header pin will just sit perfectly in place. If they don't, you have some solder blocking the header pin from sitting flush. To remove that excess solder, apply more flux and solder to the point that has the blockage. Then use the solder pump to remove the solder. This will clear the blockage. Be sure to clean with isopropyl alcohol and a cotton swab after you remove the blockage before proceeding further.
- With a cotton swap, apply some some flux to the bottom side of the header pins.
- Fit the header pins into the jumper solder points from the component side and with a piece of tape, tape down the header pins so they stay in place.
- Flip the board over to the solder side and apply solder flux to the jumper points
- Solder the header pins to the jumper points.
- With a cotton swab and isopropyl alcohol, remove the flux residue from the solder side of the work area of the board
- Finally, remove the tape as the header pin is now fixed into place with solder.
In reality, it doesn't look all that much different than from before you started this. But this photo just illustrates everything is in order now that the soldering is done with! You can now put away the soldering tools.
Now, we want to place the jumper caps over the header pins for Major Title 2 operation, and not yet for R-Type Leo operation. For Major Title 2 operation, the jumper caps should be positioned as follows:
- J8 = OT position
- J15 = OT position
- J16 = 2S position
- J1 = S
- J6 = S
The reason we don't want to position the jumpers for R-Type Leo operation yet is because we want to eliminate or reduce the possibility that the solder surgery that we performed is incorrect in some way. It allows for less troubleshooting as we proceed to the next step in the next post.
Big thanks to @ekorz for the tip pointing out that the jumper solder points are indeed thru-hole type and using header pins rather than just wire bridges to get this going correctly.