Heavy Barrel Repair Logs

Repairer: Womble
Forum Thread: Heavy Barrel PCB Repair

Usually board repair is not quick, often it takes hours, sometimes days, but very rarely you get a board that can be fixed within seconds. Welcome to Heavy Barrel.





I sniped this on eBay recently, apologies if it was an AA'er who I beat, am amazed I got it as I was bidding via an iPhone app and I had to manually enter another bid with 3 seconds to go. I mainly grabbed it as it is another Data East rotary joystick shooter much in the same theme as Midnight Resistance. Whereas MidRes is a horizontal side-on shooter, Heavy Barrel is a vertical top down shooter but a number of elements graphically are the same as MidRes, that and the fact the board looked mint and I do like Data East boards.

It was sold as having a graphics fault, but the game did still run. I had no idea what the fault actually was until it was fired up but I had a prime suspect pretty much as soon as I got it out of the shipping box.

The fault was actually that the sprites were a mess, mostly unrecognisable, often doubled up fragments of sprites.



The collection of junk on the metal platform is supposed to be P1 and P2 character sprites.



The green blobs are the enemy sprites.!



Not exactly easy to see what is going on!



The enemies were mostly collections of green shoulders and heads, Player 1 is the collection of crap in the top left hand corner.

Clearly the vast majority of the board is in perfect working order as the game code runs, the display is solid, the colours are right, everything moves around as it should and the sound works. The only thing was the sprite blocks were wrong. Having narrowed it down like that it still leaves a tonne of options for the underlying fault. It could be bad ROMs, could be bad RAM, could be bad logic, it could even be bad custom chips, or it could be that someone at some stage knocked the board and bent two pins on the board interconnect together.



They had actually bent a few but only 2 were making cross contact, I confirmed this before I straightened them out and they did buzz as connected. Often when you find something like this they do turn out to be not quite making contact. This pair however were bent together with some force and were making good contact.



So I used a jewellers screwdriver to pry them apart and some pliers to restore all the pins to their original non-bent positions; powered up and the fault was gone...



...P1 and P2 back to their original glory.



The enemy heads and shoulders now had arms, legs and weapons



And in general you can now see what the hell is supposed to be going on!

Hopefully in a few days my LS30s will arrive and I can actually play it properly on a vertical cab

Repair Logs converted to wiki format by Brad from Aussie Arcade.