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fuzzy sprites on black background?


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#1 ubersaurus OFFLINE  

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Posted Wed Feb 8, 2017 6:59 PM

Hey, I noticed something weird, and it doesn't seem to happen on every 2600 console, but has anyone else noticed certain sprites being really fuzzy and indistinct on black backgrounds? Specifically I've noticed it with the base in Space Invaders and the blue ghost in Ms. Pac-Man during the title screen on a revision 14 and revision 17 4 switch. This doesn't happen on my 2600 Jr. or my 7800. 

 

I don't know if it's just the bright colors are too intense for my 2004 CRT tv, or what exactly, but I was curious if anyone else has seen this occur and if they were able to do anything to adjust it?

 

(I've noticed a similar phenomena on my Channel F console)


Edited by ubersaurus, Wed Feb 8, 2017 7:03 PM.


#2 Thomas Jentzsch OFFLINE  

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Posted Thu Feb 9, 2017 3:45 AM

Maybe you have too much contrast or color in your TV's settings?

 

Pictures would help too.



#3 ubersaurus OFFLINE  

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Posted Thu Feb 9, 2017 8:04 AM

I can see about getting photos tonight. I took another look at it last night - it's like the images are "ghosted" for those specific sprites. it's really noticeable on the Space Invaders base. On the Channel F its more of a general ghosting/fuzziness regardless of background color.

 

It could be a tv issue, but it would be an odd one of it is - I don't remember ever seeing anything similar on the 5200, 7800, Intellivision, Colecovision, Odyssey2 or relatively newer consoles. It's pretty much just relegating to four-switchers and the Channel F. I also tried different RCA cables for the 2600, but it's still ghostly.



#4 maiki OFFLINE  

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Posted Thu Feb 9, 2017 8:23 AM

Generally, from what I have observed on my Jr., there are certain color combinations that do not display clean. Similar well known situation on C64C (even with composite connection). I think it is standard and normal and developers should be aware of this when selecting colors.



#5 ubersaurus OFFLINE  

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Posted Sun Feb 12, 2017 5:32 PM

It took a minute before I hooked it back up, but here's a few photos of what I'm talking about. Could it be an RF modulator issue?

Attached Thumbnails

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  • IMG_3833.JPG


#6 ubersaurus OFFLINE  

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Posted Mon Mar 13, 2017 7:50 PM

Just an update. I figured out the incorrect color issue (extra unneeded resistor soldered to the underside of the rev 17 board). I also had some extensive maintenance done on the board too - new capacitors, new voltage regulator, replaced some janky switches, new power jack. The fuzzy display thing persists, though. Still pronounced on the blue ghost in Ms. Pac Man and on Pitfall. I've also ruled out the RF cable, as I tried a different one (and the current one displays nice and sharp with my 2600 Jr console).

 

Anyone have any other thoughts on what the problem could be? I'm pretty much out of ideas, and I can't honestly believe it's just an artifact of this board revision.



#7 splendidnut OFFLINE  

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Posted Fri Mar 17, 2017 4:08 PM

The blue line around the HMOVE area appears to be way too bright.  Just a shot in the dark, but maybe the RF modulator is going bad?



#8 ubersaurus OFFLINE  

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Posted Sun Mar 19, 2017 8:05 PM

I guess it's possible. I had a similar issue on a revision 12 board, but after I had some work done on it (replacing a filter cap, adding the resistor to the TIA and replacing an old RF modulator) it didn't seem to be happening anymore. I didn't think the RF modulator could have been the culprit, but between the two I suppose it's the only piece not accounted for.






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