Psikyo Sengoku Blade II woes

[segasonicfan]

Got a board that I got broken with intermittent sprite problems. After looking at it I suspected the culprit was the socketed PALCE16V8H-15 (U64) in the upper left corner. The socket had some major corrosion so I decided to replace it. Sadly, while doing so, something went askew and the game now boots but will not show sprites at all. I have checked connections to this chip a great many times and I believe the chip itself has likely gone bad on some input or output.

Anyone have any ideas? Its a programmed logic chip, so I think my only hope is getting another Psikyo board thats broken :/

 

[Xian Xi]

What is the logic probe saying?

 

[bustedstr8]

Does it look something like this http://imageshack.us/clip/my-videos/440/pus.mp4/


I have a working board and one with missing sprites. When I get a chance I can check the response on the PALs for you.


Edit: Check pin 16 on the 74LS273 at U3, it controls the /CE for the three gfx Roms.

 

[segasonicfan]

Does it look something like this http://imageshack.us/clip/my-videos/440/pus.mp4/


I have a working board and one with missing sprites. When I get a chance I can check the response on the PALs for you.


Edit: Check pin 16 on the 74LS273 at U3, it controls the /CE for the three gfx Roms.

HOLY SHIT! That is *exactly* what the board looks like, same exact sprites missing and all (the woman's face specifically)! Did you ever figure out the problem with that missing sprite's one? Looks like nothing's shorted on U3, but I might go ahead and replace it just to be safe....any suggestions on what to look for?

Thanks so much!

 

[Xian Xi]

Follow the logic of the chip. It usually tells you the answer as to what is wrong.

 

[bustedstr8]

On my board the Psikyo custom qfp has a dead output that clocks the two 74LS273 in the Rom section.

I tried grabbing a few different clock signals and they ranged from complete shit to decent with some screen tearing.

 

[segasonicfan]

I'm assuming you mean the qfp closest to U3? would you mind telling me which output is bad, and what the voltage is on the bad pin? I'd just like to figure out if I'm having the same problem, and if so, save myself a lot of headache chasing around for a fix.

Strange that out boards would have the exact same symptom. Any idea what lead to your qft going bad?

thanks for the help!

-Segasonicfan

 

[bustedstr8]

Pinout for chip at U3

You can check the Psikyo qfp clock output on the chip above.
You will need a probe to check the clock signal or if your meter has a counter in 20MHz range that should work.

I guess you could use a voltmeter to check all the ouputs (1Q-8Q) of the chip.....if they are always
stuck at one voltage and never pulsing there is
a good chance the chip isn't clocking.

Input 7D should be pulsing when ever sprites are displayed.....when you start the game and when the face of our large breasted friend is shown.

I have no idea why my chip died. I guess
chips just fail sometimes...and if they are Fujitsu logic...they fail all the time

 

[segasonicfan]

Thanks for the tips-- I checked everything out, even replaces U2 and U3 with new chips...no luck.

7D and everything else for that matter isn't pulsing and it so it would seem we have the same symptoms going :/

I wonder what happened with these boards? One thing, if you're able to check it on your working board, is the voltage on Pin 12 of U64 (the PAL in chip). It's tied to Pin 1 of U53 (74LS374) and on my board that pin got shorted to ground (in the 74 logic chip). I replaced it and now it reads ~5v. Unfortunately I doubt there's any way to get a new PAL, but it might be nice to know that reading just in case.

Seems you know alot more about trouble shooting this than me though, any chance you'd want to take a look at my board with your two and try to take a shot at a fix? or take some readings? I'm getting another broken Psikyo board in the mail soon, so I'm hoping to be able to swap parts to get something working here.

-Segasonicfan

 

[bustedstr8]

Just checked my bad board and U3 pin17 still reads about 2.9V when active. Let the attract mode loop once while you check the inputs on the chip. If it's not clocking like we suspect only the outputs should be dead.

I checked that Pal pin 12 with a probe and meter. It is high with a low pulse every half second or so, voltage was
around 3.8V The voltage readings could be quite different between two different meters depending on how
fast they sample.


If the problem is the qfp send the boards to Channelmaniac... he has a rework station for the needed transplant.

 

[segasonicfan]

Ah, a little bit of progress! So it looks like there was a connection error on pin 1 of the PAL at U58 (bottom of the PCB). Resocketed more correctly and voila! sprites Now they're just garbled :P Here's some videos:

http://s18.photobucket.com/albums/b134/Segasonicfan/?action=view&current=VID_20120426_101534.mp4


http://s18.photobucket.com/albums/b134/Segasonicfan/?action=view&current=VID_20120426_101456.mp4


I swapped in the old 74LS374 at U53 and the board froze, so that chip definitely went bad though I'm really not sure why. Pin 1, which shorted to ground on the original chip goes to pin 12 on the other PAL which reads ~4v. Which might be alright since we get almost the same reading. Mine doesn't seem to pulse though, I'll recheck that. Thanks for that btw, was that from your working board?

Also, I noticed even after removing both U2 and U3 (I have them socketed now) that there are some black bar sprites on powerup, so I'm thinking the problem with your board might really just be that PAL, I recommend taking a good look at it.


I'm guessing when U53 blew on my board it took something with it...maybe some of the eeprom inputs it's connected to? The nice thing is, even if I can't figure it out, between these two boards we should be able to get a working one if you're up trading parts n stuff.

EDIT: Forgot to mention that the game runs *exactly* the same when booted with or without U53 connected (I socketed it now),. Looking closer at U53, it has inputs connected to both eeproms and the 68k, so it seems like something pretty important is gone screwy... :/

 

[channelmaniac]

Got a pic of the board? Have you reflowed the surface mount custom chips (if any on that board)?

RJ

 

[segasonicfan]

Here's some easy-to-view pics online:
http://s18.photobucket.com/albums/b134/Segasonicfan/

and a RAR with a bunch more to download:
http://www.mediafire.com/?ktf11hszqa4rcuw


I've reflowed every surface mount chip on the board, except I think, the 68K I've also reflowed a lot of other circuits since I thought the original problem was a reflow issue (and maybe it was). But when I changed the socket for the PAL at U64 the 74374 at U53 blew. I replaced it and rechecked connections and it's not blowing the chip but I wonder if the PAL wasn't damaged.

Thanks for your help!

-Segasonicfan

 

[segasonicfan]

bump...

 

[hezkezl]

Well, I think that this exact board is now in my ownership, and I'm trying to fix it.

Pin 20 on mask rom U1 is floating (data line 11), so I think the chip is bad, and the root of the garbled sprites (according to the mame source U1 is the sprite lookup table).

The rom is an SMT 40 pin LH532GNH, which I can find absolutely zero information about. Does anyone know what a compatible rom would be for this that I can program the mame .bin onto?

 

[bustedstr8]

29F200 comes in a SOP44...you will need to jumper the extra control lines to +5V.

 

[hezkezl]

I ordered some 28f200-80 eproms. I hope they will work. I'm not sure what the difference between the 29f200 and the 28f200 is, but I guess I will find out soon enough if it's okay

 

[hezkezl]

Well, I reflowed pin 21 on u1 and it's pulsing now, so looks like I may have bought a handful of eproms for no good reason I'm sure they will come in handy sometime in the future.

The sprites are still wonky, but I think it has to do with either the flip flop array at u3, or the traces from the sprite LUT at u1 to u3.

Do you still have a working board? (I know I'm reviving. 2 year old thread)

Q8 and Q9 on U3 are pegged low for me, and 5D, 6D, and 7D are floating (5Q, 6Q, and 7Q are pegged high) what do these pins look like on your board?

 

[hezkezl]

I removed the socket from U3 and traced the D lines back to the Sprite LUT at U1. There were 4 pins on U3 that weren't getting signal, so I jumpered them to the appropriate pins on U1.

I still have some garbled sprites, but about half of them are actually showing up correctly now. I am going to repeat this process on U2, and hope for the best.

 

[hezkezl]

Success! Fixed up the connections to U2, and this Tengai lives to see another day!

 

[kuze]

Nice work! Pretty cool that you were able to resurrect this board after this two year thread.

 

[bustedstr8]

Sweet.....someone just needed to show that fat titted bitch who was boss