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CPS2 multi crackling audio

Well, I believe I've found the problem and this is due to poor quality 5V coming from B Board that combined with very high quality and too sensitive 74LVC4245A will make the bus open/close when it shouldn't due to those power fluctuations. This is not an easy fix, so we are trying to find what would be the easiest way to fix it for every users. Those Chips are very tiny and soldering there is not for everyone.

We'll of course offer our best support, but now we are working on how to make the simpliest most straight forward solution.

We'll get back when we know more.
 
Would a different/better power supply help? Or fixing the Aboard to deliver perfect 5V?
 
mrJAMMA said:
Actually jassin000 , what happens if you unplug the LCD altogether? I might try this tonight if I get a chance.

Also, whats the ebay link for that rainbow cable - wouldnt mind keeping that handy
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This is the cable I ordered from Ebay... I've never used the multi without the LCD screen attached, so I couldn't say.

I was going to try it next time I opened her up, but Guru above says it won't affect the issue, so I'm not rushing.
 
nio said:
Would a different/better power supply help? Or fixing the Aboard to deliver perfect 5V?
Click to expand...
it's more due to dozens of chips being in close proximity to each other and stray electrical signals interfering with the normal operation because the chips are sensitive. setting the 5V at 5.0000000 won't help.
If you look at the tracks on a typical PC motherboard running at several GHz, they make the tracks longer in U or W patterns. I'm guessing it's not because they enjoy making pretty patterns on the PCB tracks. It's more likely to do with minimizing interference or perhaps purposely causing a delay of a few micro-seconds or whatever. it's a very advanced design thing, not just for looks.
 
The major reason for zigzag-ing traces on high speed buses is make it so all signals (in a bus) reach the chip at the same time (make so all signals have to traverse the same distance in coppper). Another stuffs like capacitance and induction are considered when deciding where each trace will go to. As Guru mentioned.
 
that could be related in the case of the CPS2 multi-game board.
It zigs but the zag is missing!
hey Darksoft, problem solved!

hehe!
 
l_oliveira said:
The major reason for zigzag-ing traces on high speed buses is make it so all signals (in a bus) reach the chip at the same time (make so all signals have to traverse the same distance in coppper). Another stuffs like capacitance and induction are considered when deciding where each trace will go to. As Guru mentioned.
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AFAIK that's the reason why they do it, so that all signals traverse the same amount of mm of copper. This is also the reason why they changed the hard disks from ATA (parallel) to SATA (Serial). The speed was so high that a very small desync of one bit and you get an error...and with so many billions of bits going through, the higher the speed, the higher the probability of data loss. With serial, you don't have that problem, one bit at a time :)
 
OK. So I can confirm now that the problem of the crackling has been identified and is coming from Chip U40 located at the upper-center part of the Main PCB.

The 74LVC4245 used there are too fast for the bad power quality coming from the B Board. This makes that the chip reacts to small current fluctuations and creates clashes in the data bus.

The only solution that can be applied is changing the U40 for a new tiny custom PCB that I'm going to order today.

Once I receive them, they'lll be tested by me, Mitsu and others so we can confirm 100% it's working.

Once this is confirmed to work, Everyone who wants one replacement will get it completely for free. You should contact Darksoft for any location Worldwide except USA + Canada or contact Mitsurugi if you are based in USA or Canada.

As you can see by the size of U40, this is a tiny work not suitable for everybody ( check position and size of U40 to make sure that you can replace that)

You can source someone local to do the soldering or send it to us for a replace. You'll need to pay return shipping if you want us to replace it.

All kits from now on will already have the update installed.

I'll keep you updated.
 
no crackles here. mine is working just fine ;-)

:-D :-D :-D
 

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Guru has offered himself to do the update for people from Australia and NZ. That will ease things definitely.

Once we announce that the replacements are ready, and you can send your kit, make sure that you send the CPS2 multi plugged into their B board for protection (dont send LCD) or ship multi board separate but with some protection foam (like styrofoam) on the bottom where the pins go down and everything very well packaged.
 
they could send now and I'll add 8 wires. they will have special 'prototype' CPS2 worth big dollars in years to come hehe! :-D
 
So...is it confirmed that the fix Mr T Guru did works perfectly? with all games? if it does, I think that should be the implemented fix, as opposite to waiting for the custom boards that Darksoft will order and make him not spend more money, shouldn't it?

Thanks!!
 
aha2940 said:
So...is it confirmed that the fix developed by Mr T Guru works perfectly? with all games? if it does, I think that should be the implemented fix, as opposite to waiting for the custom boards that Darksoft will order and make him not spend more money, shouldn't it?

Thanks!!
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What do you mean?
 
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