Game booted without problems but it was missing music and sound effects.
The amplifier was working correctly as I could hear the typical white noise coming out of the speakers.
As you can see, the game is upside down and checking with Mame there is no flip dipswitch so unfortunately is one of the few horizontal arcade games which has the screen upside down (the other that I know is Athena from SNK).
Another thing you should have noticed is the copyright…..some smart italian arcade owner has hacked the original date from 1985 to 1987 to make the game looking newer….it’s unfortunately very common in Italy.
back to the real problem, I checked with my portable amplifier the input to the operational amplifier and there was no sound.
That meant that either the DAC was faulty of something in the sound circuit logic.
The DAC is a YM3014
The SD pin is the output of the YM2203 which is a digital waveform so normally you cannot check with an amp if the YM2203 is working or not.
The only thing you can hear is white noise but there is a trick: compare the breaks between melodies (example, between coin up and start game), so the YM2203 should also stop orstart again to output signals.
With this trick I could confirm that the DAC was faulty.
Replacing the YM3014 with a good one fixed the problem as expected.
I bought this faulty pcb from ebay at a very cheap price.
The seller mentioned that it had a “service switch error” and didn’t boot.
When I received it I could confirm the behaviour:
Several Taito games from late 80s to early 90s use a custom chip marked TC0220IOC which handles the inputs.
Looking at Final Blow schematics, the pinout is well documented so I started to check service signal which infact was always low on pin 36 of the custom chip
Before desoldering the custom chip, I checked the continuity of the Taito network resistor RRC4 (on Fighting hawk pcb) and I noticed that it had a very low resistance (less than 1Kohm) to +5V in comparison to the other pins which had a 10kohm resistance.
So, for what it costed I proceeded to desolder the network resistor and see if the pcb booted.
The game did boot infact and it was a good sign, meaning that the problem didn’t come from the custom chip.
I found the same network resistance on a scrap taito pcb and the service switch was fixed but unfortunately the airplane was going up and left all the time and fired and thew bombs continuously.
After running the test mode, I noticed that all P1 and some P2 inputs were triggered!
To end the story short, I had to exchange ALL the network resistances except one to fix the game.
Looks like the game was connected reversed at one point and the network resistances probably protected the custom chip.
GuidesComments Off on Using a lightgun with Operation Wolf PCB
Apr052016
Some days ago I received an Operation Wolf PCB bought from Hungary.After dumped ROMs and comparing the board layout with pictures on the web it turned out to be a rare prototype which runs unprotected code (it lacks of the C-CHIP IC).I suggest you to read the whole story on David ‘Haze Haywood ‘ homepage:
After adapting the board to JAMMA, I fired it up and it was perfectly working.Reading on the Web, there are conflicting opinions if this board is a simpe lightgun game or it uses analog joystick like some many people claim.So I wanted to try myself and bought a couple of cheap Happ lightguns widely used on games like Lethal Enforcers :
All lightguns work in the same way: you’re pointing your gun at the screen, and the gun is essentially a light sensor.When the part of the screen which the gun is pointing at gets flooded in white, the sensor detects it and sends a signal to the game: “I can see white now, I’m pointing at the part of the screen you’ve just drawn”. At this point the game can work out how far down the screen it has drawn, and how far along the current line, which gives a pretty accurate position of where the gun is pointing.
The Happ gun has a 4 PIN connector and looking at Lethal Enforcers schematics, this is the pinout:
The ‘HIT’ signal (so called in Lethal Enforcers but name is relative) is an input on arcade PCBs and it’s essentially the output of the optical sensor (a phototransistor) mounted inside the gun.The ‘TRIGGER’ is the switch inside the gun and it’s shorted to GND everytime, indeed, you pull the trigger.VCC and GND are obviously needed to power the electronics inside the gun.With this info it was very simple to adapt this gun to the Operation Wolf PCB.The pinout of this board shows ‘TRIGGER’ signal on pin 21 parst side of ‘G’ edge connector on main board and ‘HIT’ (called ‘SENSOR’ in service manual) on pin 5 solder side of the ‘T’ edge connector on sound board:
For a better interfacing of the gun to the PCB I used a 4 pin right-angle male header mounted on a piece of veroboard:
Lastly, since Operation Wolf use another input for rocket and this Happ gun lack of a second switch, I added a further button (a normally-open one) mounted inside the gun and connected to internal common GND and ‘ROCKET’ signal which is PIN 4 of the ‘M’ connector on Operation Wolf main board (but if you want, you can also adapt a PSX/Saturn Guncon which comes with more than a button)
Finally now for sure I can say that Operation Wolf is a simple lightgun game.So let’s go to play it!
Some days ago I received this Konami Gaiapolis PCB for a repair:
It showed a graphical issue where some background layers were missing but pressing down the PCB they came again although in wrong place:
Hardware uses some custom ASICs to generate the various parts of graphics so I made a reflow of the two involved in tiles but this didn’t fix the issue.Using some dummy ROM files in MAME for the backgrounds data I noticed the missing/misplaced graphics were not affected so they were not really backgrounds.The board is capable also to rotate and zoom objects (‘ROZ’) and the ASIC which performs this function is the ‘053936’ :
So I went to inspect it and found this:
Two pins (connected to data lines of two 6264 RAMs) were touching each other and the rightmost one lost contact with its pad.I restored the proper connections and graphics came back in right place:
I was declaring the board 100% fixed but I noticed some palette/priority issue :
The ASIC involved in this function (it can do other GFX tricks like alpha-blending) is the ‘055555’:
A simple reflow of it was enough to fix the board completely.
