Try to repair log: Zero Team PCBs...

[channelmanic]

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!

Ah, Grasshopper...

You have learned the technique of finding bad solder joints on surface mount chips! Congratulations!

This technique has served me well... It has brought many boards back from the junk pile, including a Raiden II.

+Karma/reputation for you!

 

[mastercello]

Excellent mate...got this same game yesterday also - an absolut master piece!

Hence mine has still the battery installed and is still with the original roms.
But at some point i also will have to do the suicide fix for sure.

 

[ifkz]

I have had a request to post the information as to how I initialized the board to fix the sprite corruption after the Dead Battery Society EPROMS are installed if you have a board with this odd piggy back PAL configuration.

VAPS lists only ten of these boards and a lot of these are in unknown condition or not working. If this information gets more of these boards in circulation I will be very happy. Please post here if this helps save a board! This information has also been e-mailed to Tim at Dead Battery Society. One member is going to test it on his boards to confirm it works.

The first thing I did when I got my board was to remove the battery. I never powered it up until I installed the suicide fix EPROMS. At this point, I left the piggybacked PALS and all jumper wire alone. It booted, but all sprites were corrupt, just like a board that had suicided. The background layers were okay. I tried a couple of things. I removed the piggy back chips and installed a socket on the motherboard for the bottom PAL, and then installed a socket on the top of that bottom PAL so I could test the two independently. It would not run with the bottom PAL independently at first. At this point I was out of ideas and tried this bit of soldering.

The top PAL is an AMI branded chip at board location U0310 markings
9250MEA
18CV8PC-25

You will be using the wire running on PIN 17 on this 20 PIN chip. It should have several green jumper wires all ready. Note the point on the board where it is connected. Desolder it from the board and run it to PIN 57 on the surface mount chip at board location U096 marked
SIE15O
WA30601

See the brownish pad in the picture. Pins are clearly marked on the board's mask and this is a 100 PIN chip.
Power up the board and you should hear some sort of chime audio string along with a screen of mostly junk graphics. I did this several times sometimes the entire chime would play, sometimes it would get cut out. Only one time should be required. After this, you should be free to desolder the top piggy back chip and all of the jumper wire from the pads on the board. Keep the bottom one where it is or the game will not run. Graphics should now be okay.

No guarantees this will work, it was a shot in the dark on my part that just happened to work. Be sure to install the four Dead Battery Society EPROMS.

Also of note: This board seems a bit sensitive to sync. Don't forget to dial it in correctly. I am using it with a rebuilt G07. This board is also part of the UnMamed set of games at the time of this writing.

 

[rolins]

I'm receiving a Zero Team pcb in the mail soon, and from the seller's photos it looks exactly like ifkz's board with the green jumper wires. The battery hasn't commited suicide yet, but when I get I want to keep it original as possible. If I replace the battery will still work afterwards?

 

[ifkz]

If you pull the battery, the code it helps hold is lost and the game will have dead sprites. I never heard back if my fix worked for the other guy, but I'll keep the post unedited. Nice to see another Zero Team unearthed, I'm sure it is in better condition than the one I started with.

 

[rolins]

If you pull the battery, the code it helps hold is lost and the game will have dead sprites. I never heard back if my fix worked for the other guy, but I'll keep the post unedited. Nice to see another Zero Team unearthed, I'm sure it is in better condition than the one I started with.

Well I'll give it try anyway. What's the harm right? If it doesn't work I can always remove the battery and replace the roms. At the DBS page it does say it might be possible to change the battery if I do it quickly.

 

[dbstallman]

I am happy to report that ifkz's fix worked on both of my dead Zero Team boards.

There is one step that he failed to remember in his earlier post (he had done it, just forgotten to put it in the step by step) and that is to repair the cut trace on the bottom of the board. The attached picture shows where to make the repair, the trace runs between the two yellow circles. For refrence, I have marked where the cut was on both of my boards with a red circle.

I left the wire from pin 17 on the PAL floating and just touched it to the pin 57 solder pad a couple of times while the board was running. I didn't hear any chime or notice any difference while the board was running, but when I powered down and removed the other two wires the boards came back up in perfect working order.

Thanks for all of your help, ifkz. You have helped me bring back a board that has been dead for about 10 years.

 

[ifkz]

That is great! Thanks for letting me know that it worked for you too. My trace was cut too, but it looked a lot like damage from poor handling over the years. Maybe it is a factory cut? It was pretty sloppily done though.

 

[DarrenF]

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.

General question related to using a logic probe:

How can I distinguish "racing data lines" from simply "active data lines"? I can find dead TTL gates, etc, with my probe... but I have no idea if something which appears "active" is actually "racing"...

 

[dbstallman]

That is great! Thanks for letting me know that it worked for you too. My trace was cut too, but it looked a lot like damage from poor handling over the years. Maybe it is a factory cut? It was pretty sloppily done though.

Both of my boards had the trace cut in virtually the exact same spot. The solder pad I connected to at the top of my picture is the one that the green wire from pin 16 on the PAL connected to on the other side of the board. That combined with the fact that it was done on both boards led me to believe that it was performed as part of adding the second PAL to the board.

 

[channelmanic]

General question related to using a logic probe:

How can I distinguish "racing data lines" from simply "active data lines"? I can find dead TTL gates, etc, with my probe... but I have no idea if something which appears "active" is actually "racing"...

If the /CE and /OE lines are high the SRAM/EPROM chip shouldn't be outputting anything. If it is you must replace it. Same thing goes for TTL. If there's no input an the output is going crazy, replace it.

 

[DarrenF]

If the /CE and /OE lines are high the SRAM/EPROM chip shouldn't be outputting anything. If it is you must replace it. Same thing goes for TTL. If there's no input an the output is going crazy, replace it.

Totally makes sense for the TTL. Also makes sense that a RAM should be outputting anything if it's not selected/enabled. But they're typically on a bus, so how can you tell it's it's THAT RAM IC or something else on the bus generating the pulsing on that (bus) line??

 

[channelmanic]

Totally makes sense for the TTL. Also makes sense that a RAM should be outputting anything if it's not selected/enabled. But they're typically on a bus, so how can you tell it's it's THAT RAM IC or something else on the bus generating the pulsing on that (bus) line??

Sometimes you can find 'em socketed where you can pull a pin out of the socket and test it separately. Other times you have to go by your gut...

 

[EagleTG]

Nice fix!!!

I, too, am plagued with a Seibu board with large amounts of bad solder. Seems like it might be a very common trend on these boards from what I've read around the web.

 

[rolins]

Just wanna give a heads up. I revived my Zero Team pcb after the battery died. Thanks ifkz, your method definitely works!

My only gripe is the USA/Fabtek logo is gone from the title screen. Oh well at least the game is back 100% and that's what counts.

 

[ifkz]

Cool, another one saved. Please add it to your VAPS. Edit: saw you had already.
I am wondering if your board also has a cut trace on the back, so far every board with this PAL configuration I've heard about has had it. Be sure to fix that too.

 

[rolins]

Cool, another one saved. Please add it to your VAPS. Edit: saw you had already.
I am wondering if your board also has a cut trace on the back, so far every board with this PAL configuration I've heard about has had it. Be sure to fix that too.

Yep, fixing the broken trace underneath the pcb was the first thing I did. I desoldered the jumper from U082 and soldered that to pin 57 of SIEI50 located at U096. Then I replaced the 4 eproms provided by DBS and Hobbyroms. After that I powered the board for the first time and graphics were upside down and garbled, but I heard the "chime" you mentioned in your earlier post. I powered off the board and removed all the jumpers and the piggybacked PAL. Powered the board one last time and what do you know it's back to normal again. I played through the whole game to make sure and its def 100% working.

Mine was exactly like yours. Piggybacked PAL, jumpers, and a cut trace on the solder side of the board. I believe this is only on the USA region pcbs.

 

[mrdion]

sorry to bump this thread, just want to share my repair. yesterday, i've just repaired a zero team with same symptom of blocky characters (like the pics posted before), but not full blocky, only partial blocky.

the board didn't have any piggied pal. no traces cut. anyway, i replaced the 4 roms got from DBS. still no change. i probed pin 17 of the pal to the custom chip, the pics garbled, but after reboot, no change.

have checked with scope any suspicious signals, i suspect a ram chip, pulled out checked good, so it was a miss.

probing custom chip pins, reflow them, no change. i tried to run the game for hours, inserted a coin so i can see a still image, then start tapping for every possible place. it came up that when i tap a maskrom chip musha-obj-2, the pic changed. i tried to resolders the pins but no change. looked on the scope, the signals looked good. try more tap, when i tap the other chip nearby, it did not affect the pic. if it was solder problem, then it should be affected, but it's not. i make sure by tapping it again after running for a while. yes, it change the pic. so, i pulled the maskrom and replace them, and walla! all is clean no more blocky characters.

 

[XianXi]

Someone sent me one of these to look at. Did all the same stuff, removed the dead battery, replaced the 4 roms, ran a wire from pin 17(U0310) to pin 57(U096) and reflowed all the pins on the custom next to the battery. It was almost completely floating.

After that, graphics came back but garbled, there were about 5 cut traces on the underside so I repaired them all, graphics got better but still scrambled.

Now it doesn't boot at all just black screen, checked the master clock and it's pulsing as well as the D71011C(U0133) clock outputs going to the customs.

The 4 program roms that were replaced now are showing high on enable both /CE and /OE.

This PCB was a bit different from the ones in the pics, no piggyback PAL, but there are some green wires under the PCB. Haven't been able to find info on this version.

Also I see in the pics that pin 16 on the 18CV8PC goes somewhere, on this PCB there's no wire on pin 16. Where does it go?

Any help is greatly appreciated.