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Mauro72

Coleco with screen out of sync may be...

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So, first off.. it's a PAL Coleco. I don't know too much about those.

 

You can test the VDP, but odds are your getting a signal. (Based on you screen shot.)

Is the a tuneable slug/inductor in the modulator? For channel freq.

The part you have circled is an old shcool inductor.

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In NTSC Colecovision, checking pin 36 of VDP chip right to center of a composite jack and GND in side should generate a stable black & white picture.

 

I don't know about PAL, but it could be the same.

 

If the picture isn't stable then the VDP chip is damaged and needs replacement.

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Hi guys...

It's a PAL version. nanochess, so i can connect a composite jack to pin36 (center) and the ground of VDP, external side of the jack (pin 1 may be, i need to search schematic of VDP).

Ok, thanks!

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Mmmmmmm... suspect discovery. A pnp transistor, 2N3906 near vdp. Anyone can confirm the value of EBC in board?

Thanks!

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Mmmmmmm... suspect discovery. A pnp transistor, 2N3906 near vdp. Anyone can confirm the value of EBC in board?

Thanks!

Replace it anyway. This transistor is a huge problem in the ADAM data drives, and probably many other applications.

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