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130XE with bad composite and s-video (chroma/luma) - Any ideas?

130XE bad video

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#1 Waynetho OFFLINE  

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Posted Wed Mar 13, 2019 8:42 PM

I purchased an Atari 130XE on Ebay back in 2001 and used it quite a bit for a couple of years until I upgraded my PC and no longer had a serial port and couldn't use APE as a file server.

 

It has been put up since 2002/3 and when I got it out recently to try out again, I discovered the video is trash.  I didn't show the RF video but it looks like the composite photos only more blurry.  Below are photos of the Pac-Man title screen and the boot screen in composite and s-video (custom cable using chroma and luma signals) and I have also included the same screens from my Sophia DVI mode for reference.  Pardon the "Input out of range" box in the middle of the Sophia photos.  My monitor doesn't like the signal.

 

Can someone give me suggestions on why my Composite and separated video look like crap?  The chroma/luma (separated or S-Video) video jumps and displays wavy color distortions like RF interference but this wasn't present when I packed up the computer in the early 2000s.  Prior to packing up, the composite was the video mode I used most and it looked good.  Now it's vertical gray bars.

 

Could this all be due to the RF Modulator going south on me?  I understand some signals (composite) come from the modulator but can that also inject color garbage into the CHROMA signal?

 

 

Boot screen using bad s-video (chroma/luma separated video) (custom cable) 

gallery_67688_2416_100104.jpg

 

Boot screen using bad Composite (should be blue but has gray bars)

gallery_67688_2416_169862.jpg

 

Boot screen from Sophia DVI (monitor shows input out of range error)

gallery_67688_2416_101143.jpg

 

 

Pac-man title using bad S-video/separated video

gallery_67688_2416_32590.jpg

 

 

Pac-man title using bad composite video

gallery_67688_2416_75642.jpg

 

 

Pac-man title using Sophia DVI (monitor doesn't like DVI signal)

gallery_67688_2416_87018.jpg



#2 Paul Westphal OFFLINE  

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Posted Wed Mar 13, 2019 8:54 PM

Have you tried the 130xe on other TV's?

 

I'm leaning towards the Modulator..



#3 Nezgar ONLINE  

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Posted Wed Mar 13, 2019 9:21 PM

what's your pinout on your s-video cable? Looks like a few of your pictures are from mismatches - ie composite going to luma (b/w vertical bars), + chroma (b/w bars with some colour), composite to luma + chroma (too much colour)

Reference: http://www.mixinc.ne...uts/monitor.htm

Double check your pinouts. Often the pre-made cables will have 4 RCA jacks (composite,luma,chroma,audio) or 1 svideo (luma+chroma) and 1 audio.

Maybe your using a very recent model TV that tries to auto detect composite from a single (Y input) on a shared use component input?

Lastly, verify your power supply is still outputting a solid +5V. Hopefully it's not the ingot supply that will likely fry your computer.

#4 Waynetho OFFLINE  

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Posted Wed Mar 13, 2019 10:25 PM

what's your pinout on your s-video cable? Looks like a few of your pictures are from mismatches - ie composite going to luma (b/w vertical bars), + chroma (b/w bars with some colour), composite to luma + chroma (too much colour)

Reference: http://www.mixinc.ne...uts/monitor.htm

Double check your pinouts. Often the pre-made cables will have 4 RCA jacks (composite,luma,chroma,audio) or 1 svideo (luma+chroma) and 1 audio.

Maybe your using a very recent model TV that tries to auto detect composite from a single (Y input) on a shared use component input?

Lastly, verify your power supply is still outputting a solid +5V. Hopefully it's not the ingot supply that will likely fry your computer.

 

I wish I could blame the cable but I built the cable myself and it worked in 2001/2002.

 

I just pinned it out to make sure there wasn't some mistake that I didn't catch way back then.  The pins on the cable (when looking at the pins, not the socket) are:

 

LUMA  *       *  AUDIO

  VID  *     *  CHROMA

          *

         GND

 

 

The S-Video is ("=" is the key):

 

LUM  *     * CHROMA

 

GND  *  =  * GND

 

Also the COMPOSITE VIDEO and AUDIO are correct on their respective RCA plugs, the outer ring is GND and the pin is the respective signal.

 

Also, the playback images were using the AV cable on my Kworld UB445-U2 USB ATSC tuner stick. SVid, Composite, etc.  The RF when I tested it, looked similar to the composite as in vertical stripes and it was using the NTSC RF input on the same stick.

 

I have used other devices plugged into the TV stick as a control test to make sure the stick isn't to blame.  They were fine.  I booted my Raspberry Pi model B using the RCA video to the USB TV stick and the initial boot "color test" is near perfect with no striping.



#5 Waynetho OFFLINE  

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Posted Wed Mar 13, 2019 10:36 PM

Lastly, verify your power supply is still outputting a solid +5V. Hopefully it's not the ingot supply that will likely fry your computer.

The PS is providing 5.12v with no load.  From the axial capacitor near the cartridge socket, I get 4.98-5.02 VDC.



#6 _The Doctor__ OFFLINE  

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Posted Wed Mar 13, 2019 10:59 PM

 do you get the key click sound out from the tv?

if no, swap the rca cables around you don't have them in the correct jacks...

switch the channel on the rf modulator?

did you try the rf out to the tuner with nothing else connected?

try a different tv?

 

no broken wires in the monitor cable?


Edited by _The Doctor__, Wed Mar 13, 2019 11:04 PM.


#7 Waynetho OFFLINE  

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Posted Thu Mar 14, 2019 8:12 AM

Yes to audio, no to broken wires.  I ohm'd out each pin last night and they all have proper continuity. 

 

One point of interest, I'm not running the top shield but I haven't done since I installed the SIO2PC mod in 2001.  Any noise I would be getting as a result of unshielded circuitry should have been present 18 years ago.

 

I'm inclined to believe the RF MOD is borked thus causing the striped image on the RF and the composite.  The video distortion on the chroma/luma is the only thing that's perplexing me.  The fact that the DVI image is crystal clear with no distortion and such tells me that the GTIA and ANTIC are unlikely to be the cause as the video from a new circuit is perfect.  If I pull the RF-MOD, I will automatically eliminate two issues (RF and composite issues) by default along with losing composite.  If that clears up the chroma signal on the separated video remains to be seen.

 

The cable started out as a standard 6' shielded RCA cable (cut in half) and a 3' section from an S-Video cable, soldered to a 5-pin DIN plug, so there shouldn't be any issue with shielding of the cable.



#8 Nezgar ONLINE  

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Posted Thu Mar 14, 2019 11:05 PM

So the Sofia mod is in the same machine?

 

Have you tried testing another Atari with your display in question, and another display with this machine?

 How about to a real CRT instead of an LCD?

 

I'm suspecting this particular LCD display doesn't like the slightly off-spec video signal...



#9 Waynetho OFFLINE  

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Posted Fri Mar 15, 2019 8:01 AM

Lastly, verify your power supply is still outputting a solid +5V. Hopefully it's not the ingot supply that will likely fry your computer.

Regarding the power supply, it's the black brick that's labeled for use on 600XL and 800XL.  It's not a 130XE (bone colored) P/S.



#10 Waynetho OFFLINE  

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Posted Fri Mar 15, 2019 8:08 AM

So the Sofia mod is in the same machine?

 

Have you tried testing another Atari with your display in question, and another display with this machine?

 How about to a real CRT instead of an LCD?

 

I'm suspecting this particular LCD display doesn't like the slightly off-spec video signal...

Yes, the Sophia is in the same machine.  I added those pictures for reference even though I know there's an out of range error, since the image is crisp.

 

I've already been looking at options for getting Sophia to work with this monitor.  It works with my Samsung 48" HDTV.  I'm probably going to get an UP/DOWN-SCALER to pass the signal through. 

 

When I go to the info screen on the monitor, it displays CURRENT: H=62.8KHz  V=60Hz,  RECOMMENDED: 1600x900, 60Hz



#11 _The Doctor__ OFFLINE  

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Posted Fri Mar 15, 2019 8:12 AM

since it's been modded,  pictures of how the mod is installed, and if you did the mod with or without chip defeat or removal...



#12 Nezgar ONLINE  

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Posted Fri Mar 15, 2019 8:36 AM

See this post for pictures: http://atariage.com/...00xl/?p=2908506

220V variants are not known to be as problematic.

The only power supply that Atari made that was not black was the XL style rebuildable one, also visible in the pictures in that linked post...

#13 Waynetho OFFLINE  

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Posted Fri Mar 15, 2019 4:19 PM

since it's been modded,  pictures of how the mod is installed, and if you did the mod with or without chip defeat or removal...

The problems shown above in the composite and chroma/luma images were present before the Sophia mod was installed.  They weren't present in 2001 after the SIO2PC was installed because that's what I used to load programs (exclusively) since I never bought a drive or disks when I got the 130 back then.  All of my original 800XL and 400 equipment was either sold or given to my nephew in the late 80s or early 90s.

 

When you mention the chip defeat, are you referring to the Sophia mod or the SIO2PC?  I'm not familiar with that.  If you're referring to mods mentioned in my comments in another thread, those mods are not in this computer.  They were part of my 800XL that I gave up about 30 years ago.



#14 Waynetho OFFLINE  

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Posted Fri Mar 15, 2019 4:22 PM

See this post for pictures: http://atariage.com/...00xl/?p=2908506

220V variants are not known to be as problematic.

The only power supply that Atari made that was not black was the XL style rebuildable one, also visible in the pictures in that linked post...

The 600/800XL P/S that I have is the one in the lower left of that picture.  I just associate the white one above that with the 65/130XE because the color matches.



#15 _The Doctor__ OFFLINE  

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Posted Fri Mar 15, 2019 4:46 PM

Okay, I understand...



#16 Waynetho OFFLINE  

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Posted Fri Mar 15, 2019 4:56 PM

Okay, I understand...

Still willing to provide pictures if you want them (when I get home).  Just figured you were thinking it might have been the work done to install the Sophia mod was responsible for the video issues.

 

That being said, if I choose to keep the RF mod, does anybody know if there's a place to get a good replacement RF for the 130XE, or perhaps a way to bypass the RF Mod and re-create the composite signal circuitry without it?


Edited by Waynetho, Fri Mar 15, 2019 4:57 PM.


#17 Magic Knight ONLINE  

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Posted Sat Mar 16, 2019 6:36 AM

If you are ok with s-video, you can take your signals from the board direct.

See here. This mod only needs a capacitor and resistor to perform this.

http://atariage.com/...ckly/?p=4195318

#18 Waynetho OFFLINE  

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Posted Sat Mar 16, 2019 8:39 AM

Update on my off-topic search for a scaler to resolve my monitor's issue with Sophia:  The cheap Bytecc HDMI Scaler does NOT work.  It doesn't even come on when in circuit, possibly because it's not a true HDMI signal but rather the DVI data moved to the right pins.

 

I'm going to try a cheap AOC monitor next, fingers crossed.

 

Magic Knight, is there any benefit to using board level S-video mod over the CHROMA/LUMA signals?  Of course my outputs are polluted so if the board level signals are clean, that's a definite plus but I wonder if the mod actually duplicates circuitry that's already on the separated video on the board or if it's an improvement over the included signals.



#19 Waynetho OFFLINE  

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Posted Sat Mar 16, 2019 8:46 AM

If you are ok with s-video, you can take your signals from the board direct.

See here. This mod only needs a capacitor and resistor to perform this.

http://atariage.com/...ckly/?p=4195318

I see now that this mod uses the LUM/CHROM signals already existing on the board.  Let me ask this, without the mod, will I see the trash visible in the images above (color distortion and jumping/flickering)?  My cable just comes off of the existing CH and L pins on the AV jack and goes straight to the S-Vid connector. 



#20 Magic Knight ONLINE  

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Posted Sat Mar 16, 2019 9:05 AM

If you take the signals off the luma rail straight after the resistor ladder and from color signal it should be as close to the Gtia chip as possible for a purer signal.

I'm looking at The schematics over the next day or so and will see where best to put the lum and chroma connections for purest signal.

#21 Waynetho OFFLINE  

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Posted Sat Mar 16, 2019 9:44 AM

If you take the signals off the luma rail straight after the resistor ladder and from color signal it should be as close to the Gtia chip as possible for a purer signal.

I'm looking at The schematics over the next day or so and will see where best to put the lum and chroma connections for purest signal.

Obviously twisting the in and out pairs (separately) is best to reduce induced noise from other circuits on the motherboard.  Right?



#22 DrVenkman OFFLINE  

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Posted Sat Mar 16, 2019 9:46 AM

If you take the signals off the luma rail straight after the resistor ladder and from color signal it should be as close to the Gtia chip as possible for a purer signal.

I'm looking at The schematics over the next day or so and will see where best to put the lum and chroma connections for purest signal.

 

That's why Bryan's UAV board for the A8 takes most of the signals from the 4050 socket, and the foot of a resistor for the Color signal. 


Edited by DrVenkman, Sat Mar 16, 2019 9:46 AM.


#23 Magic Knight ONLINE  

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Posted Sat Mar 16, 2019 10:01 AM

I thought about making my own luma ladder with amp on a board using high end resistors and parts. Would love to know what the Gtia actually gives in performance if given a chance.

Most XL/XE units give decent outputs on this part of the circuit but fail badly when it comes to the composite or RF section. ATari designers really dumped in its own nest on that part.

#24 DrVenkman OFFLINE  

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Posted Sat Mar 16, 2019 10:11 AM

I thought about making my own luma ladder with amp on a board using high end resistors and parts. Would love to know what the Gtia actually gives in performance if given a chance.

Most XL/XE units give decent outputs on this part of the circuit but fail badly when it comes to the composite or RF section. ATari designers really dumped in its own nest on that part.

 

I presume you've read both of Bryan's massive UAV threads, but if not, they're worth it for video signal nerds. :)

 

Original production Rev C UAV

Updated Rev D UAV

 

The current Rev D is still available through MacRorie's website, www.thebrewingacademy.com







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