Display issue

[mustangus]

Could someone point me in the right direction as how to fix this. It was working fine but now i get a faint picture and lines on the screen.

[sixxie]

Kinda just looks detuned - eliminating simple things, you tried retuning the TV? Otherwise, I think I've seen similar when one of the trim pots on the video/power board is set too low (or high, not sure). Can't actually see that on the circuit diagram, I think I assumed it was setting a black level...

[robcfg]

Could you please post a picture of your Dragon's motherboard and psu board?

At first sight I'd say you're looking at a NTSC Dragon on a PAL TV.

[mustangus]

Here are some pics of the motherboard etc. Plus a picture with the monitor cable in

[jmk]

This is a bit of a long shot, but I once tried to drive a CoCo using a PSU with a lower voltage, which resulted in the screen output being pretty weak (also, it couldn't operate the tape motor).

Perhaps the PSU output voltages should be checked?

[Alastair]

Have you tried your Dragon on a different TV? We don't want to 'fix' the Dragon if it turns out that the telly is at fault.

[mustangus]

Yep I have tried it on a different TV and still the same. It used to work on this TV.

[munkeyboy]

RV1 the pot just behind the cassette and joystick ports looks very crusty, this could well be the culprit. It would be worth a gentle external clean and then note the position of the pot and give it a rotate back and forth to see if that will clean the contacts enough to improve the output.

Hope that helps, Gareth

[mustangus]

Nope that didn't work. Still the same.

[robcfg]

If you see it right through the monitor port, maybe you have to adjust the modulator.

I think the two holes in the shiny metal box on the left of the psu board are for adjusting it. Try using a small screwdriver there and see what happens.

You can also open it and take a picture so we can see if any component is damaged.