This baffled me for a long time but ended up being really simple.
When the player died and the Continue countdown came up, it would only count down to 7 then returned to the title screen. Logic suggests that this shouldnt be the case and checking in MAME proved it.
The problem ended up being button 1 for player 2 was stuck on.
Traced the stuck low signal through resistor array CRA3 and to a 74LS253 IC @ D19. Pulled and replaced the IC now all is happy.
I wired up the non jamma board I recently got, its a SEGA board marked up as Pitfall II but at some point the ROMs had been swapped out for Wonderboy ones. I already have a Wonderboy board and prefer them to be original so I burned a new set of Pitfall unencrypted roms and swapped them over.
I noticed the the game also had a fault where the left side of the screen was repeated on the right side. After a little tracing out I found a 74LS283 with a floating pin, I swapped this for a spare and fault fixed.
Not a fan of this game, will probably sell it.
I have decided to take a look at the Golden Axe problem today.
The problems with it are:
1. None of the inputs register
2. There is no sound
Normally faulty inputs are easy but not with the System 16 board. The inputs are controlled and isolated by 8 NEC2501 chips. I couldnt find a single bit of info on these chips but as luck would have it when I removed the chip from the board there is an alternative printed on silkscreen of TLP521-4. The datasheet for these is readily available and its description is a photo transistor. I wasnt prepared to believe that all 8 of these chips had gone so I traced the pinout back to the edge connector. It turns out that pin 4 on the solder side of the edge connector NEEDS to be connected to its own +5v as this supplies the voltage to the photo transistors and in my haste to get an adapter up and running I never wired all the points in. Lesson learnt. All inputs have now been tested working.
Next job, sound. I have dumped the 2 ROMs associated with the sound and checked them against MAME, both are good.
NOTE: The SEGA branded MPR- maskroms can be read as a 27c301 with a slight wiring mod.
There is a Z80 on the board which is the processor for the sound, this was dead. Replaced the processor and full sound is there.
Very happy to have this one up and running.
I bought this 1942 board some time ago for very little as it needed repaired.
This was my second board repair so took me a bit longer than what it probably should have.
The symptoms of the fault were the character planes moved from its starting position right to the top of the screen and appeared again at the bottom, this cycle just repeated. Also the backgrounds were all messed up and at a certain point in the rolling demo, the game would freeze.
Now for the other problems. When things are in the wrong place or not behaving as expected then RAMs are a good place to start probing. Its worth mentioning now that MAME is an excellent tool for seeing how things should be.
I checked the address lines on RAM (TMM2016) @ N10 + N11 with a scope, very weak signals on several lines. I desoldered the RAM and checked it in my ABI Chipmaster, came up as “Out of spec”. Replaced this with a known good one from a scrap board and all working nicely again.
Now I don’t have a setup capable of housing a vertically orientated monitor nor do I have any plans ever to get one so this board is going to be sold.
So, this is my first and so far only cabinet.
Its a big ass Leisure 2000 cab housing a 29″ Nanao monitor and stands about 7′ tall.
Ive had this titan sitting in my garage for over a year now and for one reason and another, Ive never quite got around to doing much with it, until now.
First job was to take that rats nest of a JAMMA loom out and neaten it up a little.
Besides the kick harness wires in the middle, the neater loom makes everything so much easier to work around
Next job, those god awful decals on the CPO, marquee and glass. First the CPO.
A few hours with a drill and sanding bit just about got all this crap off
In the absence of any new decals to go on, I opted to just spray the thing black.
It was quite a few months before I got around to choosing some new graphics.
Due to the fact that this cab is not going to be dedicated to just one game, I had a tough task deciding what graphics to have on it. After much looking around and due to my bizarre fascination to fighting games, I chose the fighting theme from GameOnGrafix (formerly MameMarquees). My order was placed and in just over a week my graphics were here. A pretty good turn around from the USA i think.
Although my cab is not “MAMEed” I do like the MAME logo and when I find an Astro City cab or similar this one will most likely end up a MAME cab.
This was my first attempt at doing anything at all with a cabinet and am very happy with what Ive achieved. When I first got this I knew very little about anything arcade other than the fact that I had grew up loving them and always wondered what magical things were inside them.
Ive learnt a LOT of new things along the way and have even learnt (and still learning all the time) to diagnose and repair my own PCB’s.
There are several forums out there that have a massive user base between them and although I am signed up to them all I settled on Aussie Arcade. A very nice bunch of people all willing to help and I thoroughly recommend people to pay them a visit if you want to know more about this addictive hobby.