Home cart buzzing and screen rolling.

[XxHennersXx]

chances of GS having CRT parts are slim, :/ best of luck. when did you get it?

 

[Billkwando]

chances of GS having CRT parts are slim, :/ best of luck. when did you get it?

Um, 06-07ish, I think. It's a honkin' ass RCA.

 

[HeavyMachineGoob]

Here's a hilariously disturbing example of what I'm talking about:

That looks pretty darn awesome I gotta say. That victory was so amazing even the TV can't handle it!

 

[LWK]

hahahah that is to good

 

[Kyuusaku]

Replace the 100uF cap on the composite output with a 470uF. Flashy effects + insufficient capacitive coupling = signal level drops past the sync threshold on lots of TVs.

 

[Billkwando]

Replace the 100uF cap on the composite output with a 470uF. Flashy effects + insufficient capacitive coupling = signal level drops past the sync threshold on lots of TVs.

Beefy!

Now that's the kind of answer I was looking for. Too bad I don't have the technical expertise to try it.

Thanks for the info though man.

 

[LWK]

Replace the 100uF cap on the composite output with a 470uF. Flashy effects + insufficient capacitive coupling = signal level drops past the sync threshold on lots of TVs.

Wait a minute, how does that work? I thought changing things with a given regulation does more damage then good, or is that for voltage output only?

 

[Kyuusaku]

????

http://en.wikipedia.org/wiki/Ohm's_law
http://en.wikipedia.org/wiki/Capacitive_coupling
http://en.wikipedia.org/wiki/High-pass_filter
http://en.wikipedia.org/wiki/Sync_pulse

 

[Billkwando]

It's usually just a matter of turning a screw/knob. When adjusting they're supposed to use a test/color bar pattern.

I don't even know if geek squad even does that type of repair. But they should if it's covered under warranty.

Meanwhile, 5 years later...

Do you know what test pattern is used? I've long upgraded to a 50' HDTV, so I'm using the CRT just for old systems, so I'm back to solving this problem. I've found that the TV has screen and focus knob/screws on the back. Is Screen the flyback voltage?

I also can get into the service menu now, and have settings like "Peak White".

I don't know how I would output a signal that would force the screen to flash so I could try and twiddle the knob until it stops.

Any thoughts?

 

[Billkwando]

I made another video since apparently I deleted the old one.

 

[Xian Xi]

Did you recap your system? From what I remember Kyuusaku saying is that when it rolls when it flashes it's due to inefficient AC coupling on the RGB lines. For the AES it needs to be 470uf caps and 75ohm resistors. Something about the TV's threshold.

Edit: LOL it was this thread he said it in.

 

[Billkwando]

Did you recap your system? From what I remember Kyuusaku saying is that when it rolls when it flashes it's due to inefficient AC coupling on the RGB lines. For the AES it needs to be 470uf caps and 75ohm resistors. Something about the TV's threshold.

Edit: LOL it was this thread he said it in.

I wasn't comfortable with it at the time, but I'm pretty sure I could do it now. Do you know where I could find a pic of the board so I'd have some idea what I'd be getting into? Also you mentioned something about being able to get me the parts cheap, which I'd appreciate if you're still willing. I had to replace a diode in my subwoofer recently, so I've gotten a little experience with through hole soldering. The only thing I'm worried about is lifting traces since the board is so old. When I did my sub I used desoldering braid. I have a solder sucker but I don't understand how to use it AT ALL. I've tried and it just makes a loud snapping sound and sucks nothing.

So it's not the flyback then? Somebody (was it you?) seemed pretty sure before. Also, is there no way just to modify the scart cable instead? There would be a lot less risk there.

Edit: Also wasn't the bending what the caps are supposed to fix, rather than the rolling? It doesn't roll on my plasma, it just bends.

 

[Billkwando]

 

[Xian Xi]

Either way, you need to swap out the caps. Remind me, what board revision do you have?

 

[Billkwando]

Either way, you need to swap out the caps. Remind me, what board revision do you have?

Before you said 1st gen or 1st revision:

http://www.neo-geo.com/forums/showt...oubleshootin&p=3561997&viewfull=1#post3561997



Is this the same one?

 

[Xian Xi]

The caps you need to swap are in the top left corner. There is a row of 6 of them, you don't need to change the one on the left, just the other 5. The resistors marked "68ohm", change to 75ohm. And just like the caps, you don't change the one on the left, just the other 5.