Page 3 of 3
Re: Broken Dragon
Posted: Sat Jul 31, 2010 8:51 am
by RWAP
Well I have replaced the burnt out capacitor on the board, but unfortunately don't get any TV output still.
Any Dragon users who live local to Stoke-on-Trent willing to help have a look at this one?
Otherwise, anyone with a Dragon 32 for sale?
Re: Broken Dragon
Posted: Sat Jul 31, 2010 1:16 pm
by admin
If you test the lines coming onto the main board and the voltages are correct then my 1st port of call would be IC15 - The SAM (MC6883) - This is socket mounted in all Dragon 32s and should be carefully tested in another known working machine (Don't put the good one in the machine you have just fixed!).
Re: Broken Dragon
Posted: Sat Jul 31, 2010 2:36 pm
by prime
RWAP wrote:Well I have replaced the burnt out capacitor on the board, but unfortunately don't get any TV output still.
Depending on what you mean by "no TV output" there is a pot RV2 that controls the DC level of the video signal if this is wrongly set it can cause the screen output to be blank, though your monitor/tv will still sync so you shouldn't get 'no signal' or something like that.
Along with Simon's advice of checking the voltages at the connector it might also be worth checking the voltages on some of the chips.
Also does anything (specifically the ICS) get too hot to touch if you leave it on for a couple of minutes ? Though the SAM (74LS783), VDG 6847 and CPU 6809 do get warm in use.
Do you have access to a scope ?
Cheers.
Phill.