Try to repair log: Zero Team PCBs...

ifkz

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I ended up with two rare Zero Team PCBs from KLOV members here. One is completely stripped of all parts that could be removed: amp screws and EPROMS. A bunch of caps have been ripped out and one three legged transistor is gone. It's pretty bad off.

Before I got that one, I had already ordered a somewhat responsive one from a for sale thread here. I got that today and I was able to compare. It is a little better off, but badly warped and mostly complete. Two resistors are gone. Any tips on straightening it out?

I just looked through my parts boards and I have enough components to fix them up, save for 4 2MBit EPROMS. Good thing I have a Raiden II parts board. Later I'll have a friend burn some resurrection chips and hopefully I'll end up with two working boardsets, one as a spare. Maybe I'll run into some more EPROMS by then!
 
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Pics? I would be interested to see a badly warped board.

I probably would not try fixing the warp. That may end up causing more problems!
 
I stayed up way too late working on the worst board of the two. In addition to the above, it also had a resistor pack that was cracked and some cut traces on the bottom. I removed a pack with the same main part number from my junk Raiden 2 boardset. After swapping the ROMS over and powering it up, the results were not promising. I went around the board again and found that the surface mounted custom had damage and several pins that were not making contact. I did my best, but one of the tiny legs snapped off. I could try to file down the chip at this point, but it may be a lost cause.

The warped board was a bit better, I restored the missing resistors but that didn't change anything. Thankfully this one still runs the game with bad graphics. I'll have to see what new EPROMS do for it.

If I get some luck, I'll snap a pic. I'm still thinking about how to fix the custom pin damage, the tolerances are just too close for my equipment.
 
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Stripped boards are highly unlikely to be working once you replace the stripped parts, they were probably someone else's scrap. Having said that, I have brought a few back from the brink, it's usually a case of replacing the parts then troubleshooting why it was scrapped in the first place.
 
Tap the surface mount components to see if the bad graphics change.

If they do then resolder the affected component.
 
Thanks, I won't feel too bad if this one ends up in the junk pile. I am glad I thought of probing of the surface mounted chip. Now I really want to get home and look for the same fault on my somewhat working other Raiden II board that is complete. The more I do this, the more I know what to look for.

I took another quick look at Womble's Dark Seal repair log over at Aussie Arcade. If I get crazy, I may try filing the chip. I know my custom still has a tiny bit of metal where the snapped let was, I might be able to solder to it with a strand of jumper wire.

Tapping the custom likely wouldn't have done anything, I think. The closer I looked at the chip, the more gaps I found between the custom's legs and the pads. It looks like it was hit hard enough to bend the chip's legs and snap a few off from the pads.
 
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broken IC legs.. Reminds me of the days of repair old 386sx chips. Using a dremel tool and a PCB drill bit. I put the board under a microscope and grind the top part of the IC. Expose the part of the broken leg and Using a leg off a donor IC. I solder the leg down on one side and use conductive expoy on the other side. A little dab of regular black expoy on top to seal and act like insulation.

That might work on your custom IC if you want to go that route.
 
Yep, not looking forward to the job. At least I learned a bit more, and I didn't trash the somewhat working set. Now that I know that unattached chip legs look exactly like attached ones, and each one needs a little nudge to make sure it is attached, I can go over the bent set and my complete Raiden II set and look for problems. Connection problems I'm good at; logic problems I haven't worked out yet. I do own a logic probe, but I have no experience with it.
 
...logic problems I haven't worked out yet. I do own a logic probe, but I have no experience with it.

No need to poke at the legs... If you take the bent board and tap on the surface mount chips while it's running you may see the screen change. if that's the case then reflow the solder joints.

As for the logic probe, come up for the repair party @ my place (date TBD) and there will be folks here that will show you what to do with it.
 
I just finished some delicate work on this, with the do's and don'ts I learned last night. I found at least ten pins that were floating on one of the customs and soldered them down. It was very careful work. After doing this, I am going to conclude my other board was not repairable. That custom had been bashed at an angle and dragged the pins along with it. Given the tight tolerances, it was a lost cause. But it was an educational lost cause.

I'll see what this board does after I get new ROMs burned. Hopefully I did some good.
 
It's pretty easy to reflow using a simple soldering iron and a bit of solder on the tip. The key is the liquid rosin flux you put down on the pins first.
 
Okay, I got the fixed EPROMS from the dead battery society page, put them in, and I am greeted by a good background later and scrambled sprites. Colors are correct now, which is better than went I started and I didn't have a background layer before. Progress?

"Some PCBs use an extra PLD (PAL or GAL) mounted on a PLD which can be removed for the battery-less program."

I don't know what they are talking about, I tried removing the piggy backed chip, but then nothing would come up.

Picture:
HPIM1353.jpg
 
Hmmm... If there are no messed up connections on the surface mount customs then check the foreground or sprite RAM.

RJ
 
I tried pulling each EPROM to see if the corruption would follow it, and no luck.

I removed a memory chip near what I assume is the custom sprite generator on my trash board and piggy backed it on the two memory chips. No luck.

I went over my work on the custom and it looks good.

No luck.

Time to learn how to use a logic probe?
 
Yup!

Pay attention to the R/W, /CE, /OE, and if those seem to be good (one of the enable lines may be tied to ground...) then check the address and data lines.

You'll probably find racing data lines indicative of a blown SRAM.
 
Because your corruption is total rather than missing lines I would focus on the address buses. You should be able to remove some roms and reduce the messy graphics to blank coloured blocks, if you can then focus on the address bus going to the empty sockets.
 
"Some PCBs use an extra PLD (PAL or GAL) mounted on a PLD which can be removed for the battery-less program."

I don't know what they are talking about, I tried removing the piggy backed chip, but then nothing would come up.

I don't think this is a fault, there is something I'm missing here with the hardware after the suicide fixed EPROMS are put in. Take a look at this post near the middle, it show exactly what my PCB is doing.

http://forum.arcadeotaku.com/viewto...sid=7240c8fe641daf0200730215152635bb&start=15

Using that, the one sentence in quotes above from Dead Battery Society, it has me thinking I need to cut something out. Take a look at their PCB. It does not have the piggy backed chip mine has. I'll post a picture later. I think I was on the right track removing the piggy backed chip.
 
I did a bunch more work today on the PCB, I replaced sockets on a wierd chip hack that Seibu did on this version of the PCB. I also found a very tiny cut trace on the solder side of the PCB. I can play the game, but it is more like Double Dragon the Block Returns! I've noticed a few things, and I need a high res scan of a different board version. You'll see


My board with the suicide fix EPROMS installed
HPIM1355.jpg


The other guy's board.
Seibu_ZT03.jpg


Notice the lack of Seibu's early hack that is on mine and also my parts board. I have tried removing the hack per the Dead Battery Society's instructions. I have tried removing the three strands of the jumper wire. I have tried removing one chip, but not the other. I am completely stumped as to why my sprites are still screwed up, they look exactly like a suicided board.

Mine.
HPIM1356.jpg


The other guy's screen before the suicide fix EPROMS.
Seibu_ZT_Dead.jpg


They are identical!!! Argh!!! I know it must have something to do with this line in the directions: "Some PCBs use an extra PLD (PAL or GAL) mounted on a PLD which can be removed for the battery-less program. Thanks Afzal!"


Every day I work on this, it gets a little better. I am surprised I haven't killed it yet. I'm so close to fixing it...I can feel it. Anyone know what I'm missing?

An interesting page on the suicide hack, I have no idea what they're talking about though...
http://seibuhack.blogspot.com/2010_01_01_archive.html
 
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Looking over the PCB, I saw a spot of previous solder work on one pad (some of the rosin left over from soldering was visible. For lack of any other leads, I soldered a piece of jumper wire to it and began to un-hook the other pieces of wire from the top piggy backed chip. On the last wire I heard a chime and got a pretty corrupted screen of characters. On a reboot, I found that some of the sprites were now drawn correctly. This proves my theory that something on the board is saving some type of data from the whatever nasty security program Seibu came up with. Now I no longer need the chip that was on the piggy back and some sprites are permanetly okay. Now I need some member to show me how to re-initialize it completely.

The bikes are now present.
HPIM1359.jpg


One of the main characters has most animations drawn correctly (the one in the pink thong), and some background elements are present, like the crowd. Later levels have boats, airplanes, etc.
HPIM1362.jpg



Can anyone help my bypass the last bit of the security on this board?
 
I went to play this partially repaired PCB tonight while the forum was down. The graphics started glitching out and I tapped around the board as I had done several times before. I found the graphics changed to a 100% clean screen when I applied pressure one of the main customs. That was something new!

This chip is the one with hair thin spaces between the legs, no room for error! I had been over this chip several times before and I gave it another shot tonight. Afterwards all I could think was...there is a Santa Claus!

I can now see how much care Seibu put into this game. When struck, enemies drop their weapons. When thrown, enemies react to walls by slamming up against them.

There are a lot of detail oriented little touches. Rats running around on the first stage for example. Innocent bystanders spot you and run away in fear.

It is a quirky beat-em up, often times poking fun at the genre. One of the special items you pick up is toilet paper, for example.

Some pictures.

Splash screen all cleared up!
HPIM1410.jpg


Character select screen all fixed!
HPIM1411.jpg


Final boss
HPIM1429.jpg


Bonus screen after the game is finished
HPIM1433.jpg
 
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