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snakeGrave

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I think I've made some progress with the repair of this board.
reset was high
and halt was reading low
I traced them both back to pin 4 (Reset) and pin 6 (Halt) on an HD74LS14 near the JAMMA edge underneath the "redsun" logo.
pin 3 and 5 on the hd74ls14 were wired together, so I thought it could be an indication that the IC was malfunctioning so I replaced it.

Nothing changed, but while probing earlier I accidentally shorted Reset on the HD74LS14 to an adjacent pin and it got this thing moving I guess. It boots with garbled graphics and I can coin up but it is not really playable.

It seems like the BG ram and OBJ ram have crapped out based on the startup diagnostic shown in my photo. I'm going to start poking around the 4 surface mount HM628128A at the end of the board opposite the JAMMA edge.

Also, I know I should have taken ekorz advice and checked the prog roms earlier but where is the best place to find the appropriate files. Would these be the (2) 4MB files from the '1945 Part-2 (Chinese hack of Battle Garegga)'
The 1945 part-2 files I downloaded do vary from the ones on my board.
 

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snakeGrave

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Problem solved for now!
Traced the BG and OBJ ram back to two socketed chips near the jamma edge.
Probing these showed spotty behavior at the address lines. I traced these problem pins back to the adjacent PLCC socket.

After replacing the socket everything seems to work just fine, at least on my supergun/test setup.

One strange behavior that still persists on my blast city is that I get a garbage screen on startup until I send a manual reset to the 68000.
I measure 5.1 V at the JAMMA edge on my blast and 4.8 when using my supergun. This need for a manual "reset" persists on the blast even when I adjust the voltage to match my supergun. I suppose one way around this is to put a push button on the reset line of the 68000? However this seems like a poor choice.

Thanks for the advice everybody, this was my first go with a logic probe!
 

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GeekMan1222

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Yep I had to replace my socket too but the replacements I got I found out were probably not of highest quality sadly... but it does fix issues. The pins on the original sockets may get loose from being socketed for so long. If you are brave you can take a pick and gently pull them back out a bit. I did this on the other socket which fixed some issues I had with sound that were happening.

The pin out info is nice I will probably save that image
 

twistedsymphony

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One strange behavior that still persists on my blast city is that I get a garbage screen on startup until I send a manual reset to the 68000.
I measure 5.1 V at the JAMMA edge on my blast and 4.8 when using my supergun. This need for a manual "reset" persists on the blast even when I adjust the voltage to match my supergun.
I don't think it's the voltage but rather the time it takes to ramp up to that voltage on boot. Loads of PCBs will have a small chip to hold the CPU in reset until the voltage has come up to the desired level. I'm pretty sure the original Garegga PCBs have one and I wouldn't be surprised if the bootleg doesn't.

EDIT: here is some info on fixing this on an original Garegga PCB: http://blog.system11.org/?p=1608
 

snakeGrave

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Thanks!
So the bootleg seems to handle the startup a little different. More like Figure 2.3 in this document. except missing the 100nf caps

I was able to get consistent bootup on my blast city by replacing the 22uF capacitor closest to the RedSun logo in my image from post 122 with a 100 uF capacitor.

Something I have not noticed until now is that I am missing a few sound effects, like only half the enemies that explode will make explosive noises and my coinup sound is not present. Time to start looking at the other socket I guess
 
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yosai

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Are the voltages ok?

Edit: Last note before I forget oddly there is a youtube video I found online documenting one of the older revision boards uses a bootleg Yamaha synth and it does really weird things if the 5V power drifts below or above 5.00V. Like the sound channels cut off or change.
Sure enough looking at some photos online it seems that some of the older revisions use some kind of weirdo bootleg stand-in for the Yamaha.
 

djsheep

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Got my @qushuang Battle Garegga bootleg in the mail today. Pretty grotty, but that's to be expected.

garegga-2.JPG


Had a bit of faith, plugged it in and was faced with this lovely unsynced shaking image...

garegga-3.JPG


I have two PVM's daisy chained. The 20M2MDA seems to sync ok for 2 seconds during the initial copyright screen, then it fades to black slowly (never seen this happen before). Also strangely, the 20L2MD monitor keeps going while the 20M2 is black, but with the crazy screen above.

Depending on the boot, sometimes it never gets past the RAM Check. When it does, I get the right hand 50% of the screen syncing only, with the left totally bugging out.

garegga-4.JPG


Tried basic stuff, reseating ROMS, cleaning the board a bit, installing the video ground as suggested in this thread. No luck, no change.

garegga-5.JPG


Also to add insult to injury, there's no audio or signs of it whatsoever.

I've read of others facing similar issues, but didn't see any clear fixes for it. Any ideas where to start looking? Not sure what revision this board is, it doesn't have the JAMMA notch. I guess you get what you pay for. #BootlegBoyz.
 
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twistedsymphony

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Also to add insult to injury, there's no audio or signs of it whatsoever.
Other bootlegs have weird audio wiring Where Speaker - is hooked up properly to the amp but Speaker + is connected to ground. So if your Supergun isn't designed to support balanced audio then you wont get any output.

Similarly if your speaker - is hard tied to ground (which is bad but a lot of superguns do this) it could be the source of some of your other issues
 

djsheep

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I’ll cranked the voltage to 5.2 with no luck. Also tried a total of 5 superguns. Looks like this is a return and replace, I think @qushuang has another lined up…
 

nnap

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I have two of these and neither will sync with the PVMs. Works fine on an actual cab though.
 

nnap

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yes, I did fix the video ground. The sync seems to be out of spec for the PVM. Could hook it up to the OSSC to get a reading.
 

nnap

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no luck, the OSSC won't sync throug the MiniGun.
 
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