Something Interesting About Bb Jasper Cap Fix On Rgh Options

[Vilpo]

Ok, was having a lot of trouble getting this Jasper 256 to glitch with Matrix Glitcher V2. It would glitch in about 30-70 seconds and most of times not at all. Now i know, i should've used the programmer to help the timings, but i didnt have one handy..
So i tried re-routing and lenghtening the wires but nothing helped. Even put the mobo on a stand so the under board wires were hanging away from the board to avoid problem, nothing helped.
I read about the 68nF cap fix on GND-PLL_BYPASS points on some forums, but i didn't have one so i used a 100nF electrolytic cap i happened to have handy and i actually got it booting quickly in ~5 seconds every time.
But, the problem was it froze randomly in the dashboard or startup logo.
So i bought a couple of 68nF metallic polyester ones to try, but with that it did the same thing. So i thought maybe its a wrong value cap so i went on to put different ones in series to lower the capacitance, to see if it helped.
So i went trial and error with the caps until i had 47nF-68nF-68nF-100nF(electrolytic), in series and then it was perfect! No freezes (in 30 minutes) and booted quick, tested many times.. This makes about 16,5nF as i calculated, but interesting here is that when i tried one 15nF one, it wouldn't glitch at all. And when i tried with 22nF one it worked but was freezing again.. I also had some of the normal polyester caps in series to make about 16,4nF and it would work almost, but froze in about 7 minutes.
So i'm thinking, could it be the one electrolytic cap helped stop the freezing, or is it that accurate about the capacitance? Or maybe there is something else at play here...
I also tried the 68nF inline CPU_RST but the had no effect on this one.

This post has been edited by Vilpo: Mar 22 2012, 11:25 PM

[Dicko316]

In my experience when the dash freezes its because the wires need re-rounting away from the the capacitor legs on the underside of the board, or another way that helps is to seperate the wires going through the holes on the southbridge, so that each wire goes through a seperate hole.

I also read somewhere that 100nf is about as high as we should go, I red this either on here or on the xbox hacker forum.

[Vilpo]

In my experience when the dash freezes its because the wires need re-rounting away from the the capacitor legs on the underside of the board, or another way that helps is to seperate the wires going through the holes on the southbridge, so that each wire goes through a seperate hole.

I also read somewhere that 100nf is about as high as we should go, I red this either on here or on the xbox hacker forum.

Ok, i didn't try separting the wires through different holes. But i didn't even think about doing this, since i've another Jasper 256 that worked fine with this same wire routing. And i've done couple falcons also with this routing.

This post has been edited by Vilpo: Mar 23 2012, 11:58 AM

[Dicko316]

Pretty much every xbox is different, Jaspers and slims have given me the most head aches. with the Slims it usually just inconsistant boot times and with the Jaspers is either getting it to glitch or it freezez, in the end it always comes down to the wiring. Some like thin wire some like fat wire, some you can wire any way some only work when you steer clear or certain areas.
I put it down to the different components used in virtually every Xbox, I dont think I've seen any 2 Xbox exactly 100% the same.