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Coco2 26-3026 help

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Hi guys, I'm having issues where the screen is just black and white ( I changed the 555 timer and check the artifacing circuit). Now im also getting random characters on the screen.

 

Here's a video of what is happening

 

 

Any help would be appreciated.

 

Sent from my LGLS992 using Tapatalk

 

 

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I would clean the board with 99% alcohol. Remove chips from the socket and clean . Then with a q tip wipe a little wd-40 on the pins and re socket everything .. especially the big chip near the video out, that's the video chip

Edited by MrDave

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I think Mr Dave is on the right track.  In particular, remove the VDG chip (MC6847) near the RF modulator, and check the RF modulator solder connections for a cracked connection, something like that can be fixed pretty easily by simply reflowing the solder on any cold (cracked) joints.

 

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Yes i should be a little more detailed about ckeaning the board. UNPLUG MACHINE Use compressed air.. alchool & swabs to clean your board Then  inspect for any faults . Like john said cracked solder joints... check all the capacitors if they have leaked or are bubbled up slightly on top.

Even without test equippment you can do alot.

Good luck

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Ok so I got it working. The 2n3904 Q2 was bent and two legs touching each other. Thanks for the help.

Sent from my LGLS992 using Tapatalk

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Hey that's good news.. one of the best tools for older boards  is your eyes ! If it does not  look right., it probably isn't. 

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