Some PCBs kicking my butt

XianXi

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Big Bang
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Missing sprites, narrowed it down to one of the roms. Rom tests good has 100% continuity with the board as well. When I remove the rom and boot the game it makes no difference to the graphics. CE and OE flash normal during attract mode.


Gaiapolis EAF
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Board boots to RAM/ROM test says these are all bad:
4C, 4G, 7K, 7L, 9C and 9F

Verified socketed chips, tried the eeprom reboot with no change. Reflowed all the QFPs and no change.


Super X
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Games has missing background graphics, all roms verified. OE and CE lines flash as normal. I noticed in some pics on the net that they use some resistor packs but on the board I have there isn't any for certain roms but has factory soldering plugging the holes.


Pink Sweets - Cave
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Board works intermittently. When powered on the board has status lights D1 and D4 lit. Looks like it will boot then goes to black screen with status lights lit. Already changed some caps on the +5v and +12v line that weren't reading correct and no difference. The only other caps are used for filtering which I don't think would cause these problems unless Cave SH3 boards are known for it.


Atomic Robo Kid - FIXED
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Coin up stuck error. Resistor pack was showing it bad, rebuilt a new one and error still exists. IC handling the coin in is under the metal box in the middle of the board. The box supposedly is some type of suicide battery enclosure.
 
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When self-test reports bad ROMs but they verify good in a reader, then you check, in order:
  • Voltage on VCC pin of suspect ROM (low voltage here indicates a problem in the PCB traces or edge connector, assuming your PSU/wiring harness is good)
  • Solder joints on the ROM or its socket (whichever applies). Also check the socket itself for bent wipes or other damage.
  • Traces coming off the ROM. Continuity check from the base of the pin on the ROM, to the pin of the component it reaches.
  • If you've gotten this far and not found an issue, try replacing the IC(s) on the other end of the address/enable lines.
Note: as a rule of thumb, any joint or connection near your multimeter probe is slightly suspect even if it tests good, as the light pressure applied by your probe is likely all it takes to make a connection temporarily.

Moving on...

Flaky filter caps can cause all sorts of stupid issues, ESPECIALLY intermittent problems. Completely recapping the Pink Sweets board is a good idea.

Can't help you on ARK. I can't find any good information at all about that hardware or what may be lurking inside that box. If it's any consolation, it's listed as "good" on MAWS, so a de-suicide mod should be perfectly doable.
 
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Thanks for the help dude.

On the big bang I figured out that the rom I thought it was is actually for the voice samples which is why it made no difference when I pulled it and had the sound low. But I did narrow it down to a rom near the jamma edge. Starting to look like one of the custom quad chips are bad.
 
Big Bang came down to a custom chip that I can't replace.

Pink Sweets came down to the Altera Cyclone chip, it either needs to be replaced or reflowed.
 
The metal box has no suicide battery so thats nothing you need to worry about :)

About Super X.. i dont know if you seen my pic of it? it is detailed enough to spot differences easily.
pic here:
http://arcade.ym2149.com/pcb/ntc/superx_pcb_partside.jpg

Thanks dude. Ya the Super X doesn't have the 10k resistor packs on M01-M05, I might have to build some and see what happens. Are those lines needed to be held high?
 
One thing I noticed today is that on Gaiapolis there is a part near the jamma edge that gets very hot. Looks kinds like a resistor pack but taller. What are they?
 
Hybrid modules. Chips, transistors, coils, caps, resistors... who knows what is on 'em until you take something to eat all that crap off it if... Something like fuming nitric acid. YUCK!
 
Hmm, I wish I didn't scrap another Konami board that had similar ones. From what I remember you just have to slice the very edge and it peels off.

According to the PCB marking it has markings R B G and nothing for the 4th so I'm pretty sure it's for video.
 
Pull up the schematic for any 90s Konami board you can find but they are probably in the final stage of the video signal construction.

Always keep boards you scrap, goldmines for parts.
 
Gaiapolis EAF
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Board boots to RAM/ROM test says these are all bad:
4C, 4G, 7K, 7L, 9C and 9F

Verified socketed chips, tried the eeprom reboot with no change. Reflowed all the QFPs and no change.


Just an update to this fix.

I checked the PCB again last night and looked at the error screen again and noticed that it shows what section is being tested. For these errors it said they are the sound section. So I probed the Z80 and it was completely dead. Only lines that showed anything were ones that had pull-ups and pull-downs and the reset circuit.

Swapped in a new one and it came right up with it's glorious music.
 
Just an update to this fix.

I checked the PCB again last night and looked at the error screen again and noticed that it shows what section is being tested. For these errors it said they are the sound section. So I probed the Z80 and it was completely dead. Only lines that showed anything were ones that had pull-ups and pull-downs and the reset circuit.

Swapped in a new one and it came right up with it's glorious music.

Good work james you saved a very rare board. It took me years to find mine and just like yours I had to repair it. Now you must fix that Pink Sweets
 
Good work james you saved a very rare board. It took me years to find mine and just like yours I had to repair it. Now you must fix that Pink Sweets

Thanks dude. The Pink Sweets was already returned to the owner. Sadly there is basically no info regarding the SH3 hardware. The only person who can fix them of course is hording the info so he can profit off the entire Cave community. Sad.

As for Big Bang, it's coming down to a custom, latch or gate.

For Super-X, right now it doesn't even boot. As soon as it powers on it just starts playing music. I think this board is gonna be the biggest problem.
 
@Gaiaplois Repair - nice one James!
Great Konami Game!

How do you do QFP's reflow? Any tips or hints? Would love to learn how to do it as well.

Cheers

Main thing is liquid flux, I use some solder paste with a wave soldering tip which is similar to chisel tips on other soldering stations.

This is a good video showing how to do it good:

http://www.youtube.com/watch?v=erb6-i54tbo
 
Yes, that's a very good example. I have always seen people using chisel or "hoof" tips for this method, personally I have always just used the conical tips.
 
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