1084 monitor Composite distorted

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This monitor have had this issue for a long time. It works with my A1200 on RGB without any issues but when I connect the Composite input the image gets distorted as the monitor gets hot.

At first I thought it was a capacitor problem so I ordered a  cap replacement kit and recapped the whole monitor pcb but the problem persist.

Any of you guys have had this issue before?

Here are some pictures;

RGB (DB9) No issues






Composite Issues

After 5 min



After 15 min



After 1/2 hour.

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Here's the pictures, sorry

First Two are on RGB showing that its working. The last three are the distorted image

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Following up on the threat I discovered that the problem happens only when I connect any NTSC source, It doesn't happens with as PAL source.

NTSC source problem is present on Composite, SEP.,RGB
PAL source problem not present on Composite,SEP., RGB

So I changed the IC TDA4570 (NTSC Decoder) But the problem persist :angry:

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Heres a photo of the mainboard