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damon@everythingvirtual.net

Intellivision Text/Image Goes Weird after boot

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I have an original Intellivision that has a composite mod installed from Retrofixes (http://www.retrofixes.com/2016/04/intellivision-composite-av-mod-kit.html)

 

Having issues with shadows and ghosting immediately after boot. 

In the video it looks great at boot for a split second then gets worse and worse. Gameplay does not look to bad but there is definitely issues with color in games. 

https://streamable.com/a2egbz

*The flashing in the video is my phone camera and not present on the real world Intellivision. 

 

Voltages at the power ribbon cable to the motherboard measure @ 5.05v , 12.29v, 18.59v, 0.018v , -2.136 

 

I bought a spare parts Intellivision used to attempt to swap components but I never determined what was wrong on the spare parts Intellivision. 

Swapped the ATSC Tuner / Color IC / STIC / ATSC Tuner and power supply each one at a time but the issue in the video (above) has stayed the same. 

 

Any ideas/fixe would be much appreciated. Still pics have been attached to this post. Capkit has been ordered as it has original caps which are kinda old at this point. 

 

 

20210919_203213.jpg

20210919_203120.jpg

20210919_203057.jpg

20210919_203047.jpg

Edited by [email protected]
voltage mistype on ground

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All of the composite mod kits I've installed seem to behave differently depending on the TV being used. Retrofixes like you have, will sometimes cause a slight curl or tear in the screen on my PVM on the bench. Looks fine on my large flat panel in the game room but ONLY if I connect the composite directly to the composite input on the TV. When I connect it to my Extron composite input, it is much darker and will show some ghosting off of text etc. 

 

I had one client that the ONLY composite kits that work for them are the ones sold by Winzmod off ebay or at least that is where I got them from. I've had better luck lately as far as consistency with various TVs using the kits from Mobius.

 

 

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Posted (edited)

CrossBow,   Thank you for the recommendations!

 

If have made some big progress since doing the cap kit. I have not installed the 2N3906 Transistors yet but I have installed all the caps + the ceramic cap. The voltages from the power supply basically went from close-ish to perfect which is nice. 

 

I have noticed on my Panasonic ct-1383y some weird issues with the BNC video connectors. If you push the BNC and rotate it to lock into place the video signal bumps up in brightness and tons of shadows appear. Let the BNC connector out a bit and the video signal becomes 200% better looking. Colors are still not perfect but its a big step in the right direction. 

 

NES looks much better now and strangely with the RCA 2 BNC connector to the BNC on the TV The nes lightgun will not work or be way off on shooting. If I let the connector out a bit (rotated but still connected) the gun works with laser precision. Not sure what is happening with the BNC fully locked. It may be related to the fact that security video cameras were originally intended to be plugged directly into the TV so they need some amplification? 

 

I'd like to try some additional mods listed on Intellivision wiki for improving the RCA mod video quality:

http://wiki.intellivision.us/index.php/Intellivision_Composite_Video_Modification

 "Some have reported artifacts associated with this modification that can be overcome with slight tweaks.

  • Smearing of bright areas: Add a large capacitor between +5v and GND on the board. FABombjoy on the AtariAge forums suggests 2000µF.
  • Color shift near top of image: The root cause of this is unknown and is not seen on all systems. FABombjoy has had success with replacing the 22Ω resistor with a potentiometer and tweaking to a higher value. Values around 50Ω - 60Ω alleviate this problem. "

I'll update later with before and after pics. 

 

 

Edited by [email protected]

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22 hours ago, [email protected] said:

CrossBow,   Thank you for the recommendations!

 

If have made some big progress since doing the cap kit. I have not installed the 2N3906 Transistors yet but I have installed all the caps + the ceramic cap. The voltages from the power supply basically went from close-ish to perfect which is nice. 

 

I have noticed on my Panasonic ct-1383y some weird issues with the BNC video connectors. If you push the BNC and rotate it to lock into place the video signal bumps up in brightness and tons of shadows appear. Let the BNC connector out a bit and the video signal becomes 200% better looking. Colors are still not perfect but its a big step in the right direction. 

 

NES looks much better now and strangely with the RCA 2 BNC connector to the BNC on the TV The nes lightgun will not work or be way off on shooting. If I let the connector out a bit (rotated but still connected) the gun works with laser precision. Not sure what is happening with the BNC fully locked. It may be related to the fact that security video cameras were originally intended to be plugged directly into the TV so they need some amplification? 

 

I'd like to try some additional mods listed on Intellivision wiki for improving the RCA mod video quality:

http://wiki.intellivision.us/index.php/Intellivision_Composite_Video_Modification

 "Some have reported artifacts associated with this modification that can be overcome with slight tweaks.

  • Smearing of bright areas: Add a large capacitor between +5v and GND on the board. FABombjoy on the AtariAge forums suggests 2000µF.
  • Color shift near top of image: The root cause of this is unknown and is not seen on all systems. FABombjoy has had success with replacing the 22Ω resistor with a potentiometer and tweaking to a higher value. Values around 50Ω - 60Ω alleviate this problem. "

I'll update later with before and after pics. 

 

 

I've not tried any of those fixes as I honestly haven't really seen the smearing issue. The ghosting issue just varies from system to system and from TV to TV. So I just get what looks good on my PVM and LCD in the workbench and have to call it good from there.

 

Also, all of the current composite mod kits for the Intellivision are based on that circuit in the Wiki far as I can tell. The ONLY exception for this, is Crayon's new RGB board with the expansion board. His board is creating usable RGB output and then the expansion converts that RGB into a new composite or s-video output. I've not seen it for myself or tested it (though I do have the expansion boards) but I would at least expect that setup to provide a more consistent result across the board of all systems and TVs. But it is a more costly solution since you essentially are installing an RGB board and then getting composite and s-video from that.

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