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Trying to get passed square one
Posted: Thu Feb 18, 2016 8:43 pm
by markjp
My son has just inherited a Dragon 32. When we connected it to the tv and switched it on we just get a green square. No text ir anything. Any ideas?
Re: Trying to get passed square one
Posted: Fri Feb 19, 2016 7:18 am
by fbnbmns
Hi markjp,
first of all welcome to the Dragon Archive Forums
Regarding to the fact, that you have a green square you have a PAL Model. (please correct me if I'm wrong).
Could you make a photo of the motherboard of the Dragon and post it here?
Cheers,
Fabian
Re: Trying to get passed square one
Posted: Fri Feb 19, 2016 11:12 pm
by tormod
Hi Mark. welcome! The good thing is that your video chip (6847 VDG) and circuitry seems to work
I don't know if a broken SAM or CPU, or even a partly broken VDG, can cause this, but I know a bad power supply can. I once powered the Dragon accidentally through the printer port from a USB port, and the green empty square appeared. So check all voltage levels going to the motherboard.
The best thing would be to poke around with an oscilloscope, otherwise I'd suggest exchanging the socketed ICs with known good ones.