JAMMArcade.net – Page 259

Teenage Mutant Ninja Turtles – Turtles in Time repair log #1

Feb 012011

Got this TMNT2 board today cheap because it had a fault of slight graphics corruption.
The intro sequence was a bit of a mess and was very responsive moved.

I ran the built in MASKROM tests and 3K and 3L came us a BAD.

As one of the ROMs was socketed I removed it tried to dump it, I got a positive match from ROMIdent. As a little test I powered the board up without the ROM in and ran the test again, this time 3K showed up as BAD (it was removed) but 3L showed as GOOD.
I then corrupted the same ROM file in MAME and ran the MAME version, I had managed to reproduce my fault.

After much probing and head scratching I found that the enable line of ROM 3K must have a break in it under the solder mask of the PCB and was quite intermittent. This line is “active low” and when it goes open circuit (or dead) the chip enables and corrupts the data being sent as both 3K and 3L are sending their data together.
I traced the line back to its source which was pin 8 of a 74ALS04 at location 18F. I have ran a link from here to pin 12 of the ROM and the board now plays perfectly and passes all tests.

Single unit black CPS2 Marvel vs Capcom

General Comments Off

Jan 172011

Today I received my latest CPS2 acquisition, but in it black metal case and single board guise.
I haven’t seen too many of these black units for sale so when I did I jumped at the chance to get one.

When I inquired about this board the seller told me the suicide battery was replaced 6 months ago, when I opened up the case I find the original battery in place and the end of life date on it was 2011!
The battery cannot be replaced like the other CPS2 units, if I remove the battery as normal the board will suicide, the battery change has to be carried out with the power on. Not a massive problem but extra care needs to be taken not to short anything with the soldering iron whilst changing the battery.
Another thing to note is that should the board suicide its not a simple matter of erasing and writing new code to the EPROM’s. These boards have a SIMM with 48pin TSOP flash ROM’s fitted. I actually do have an adapter for these so its not a massive loss if I get a suicided one but I do prefer my boards to be original if possible.

I changed the battery and tested the game with no problems.

SEGA Saturn region/Hz mod

Mods Comments Off

Jan 162011

Got myself a cheap Saturn with controller, leads and a couple of games so decided to try Sebs switchless mod.
I wont write another guide to this so ill just link to Sebs homepage, the code for the PIC is on the last page.

Note: The motherboard of my Saturn was different so all the JP’s were located in different places, front and back but they all still apply the same.
Sebs Switchless Saturn mod

This mod will also work if you have a modchip fitted and it also works with the hot swap method.

The hot swap is performed by opening the Saturn and placing some tape over the lid switch so it always thinks the lid is closed.
-Power the Saturn up with the backup disc in and wait until the drive access light stops flashing
-quickly remove the backup disc and insert an original, the drive access light with flash 3 times quickly when this happens remove the disc and replace it with the backup.

If you did that correctly the backup will boot and play normally.
When attempting this trick make sure you set the switchless mod to the same region as the backup disc otherwise the game will not boot.

CPS2 Progear no Arashi (Conversion)

General Comments Off

Jan 102011

I got my hands on this very rare and expensive game today.
Although this game is a conversion and not original it still normally has a high asking price and this one was no exception!
I initially tested the board and found it wasn’t a Phoenix but it uses another set of decrypted code, this looks like it is already in MAME so I wont dump it.
Inside, all the GFX ROM’s are now 27C322 EPROMs and there is a small wiring mod too.
(Apologies for the picture quality here)

Im not sure if this mod makes the conversion work or if it is part of a repair, I cannot see any signs of track damage so ill assume its part of the conversion.

Being a conversion, the game also didn’t have a label. I have a decent scan of the label from Progear both the Asia and Jap versions so I printed one off and it now looks much better.

The game works just fine and is probably the closest I’m going to get to owning this game, a genuine Capcom release goes for a lot of money.

Dreamcast SD Card mod

Guides, Mods Comments Off

Jan 082011

Finally got around to starting the Dreamcast SD mod and its all over and done with in 15 minutes.
It involves soldering 7 wires to the back of the serial port and soldering them directly onto an SD socket. I used a cheap sd card reader as a donor.

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