Looking at H-sync it seems to jump down voltage, which seems to be when the monitor goes out of sync.. no idea what would cause that though ?
h_sync.png
Re: Falcon H-sync fault
Posted: 06 Sep 2018 14:15
by exxos
Comparing my Hsync with the faulty machine..
My test machine
ve.png
Faulty machine.
v1.png
So looks to me like the Video is faulty as I am tapped right into pin 3 on it... :roll:
Re: Falcon H-sync fault
Posted: 06 Sep 2018 17:06
by SolderGirl
Might be a bad chip.
But, is there a pull-up somewhere in this signal path?
I can imagine that a broken pullup could look similar
Re: Falcon H-sync fault
Posted: 06 Sep 2018 17:41
by exxos
SolderGirl wrote: 06 Sep 2018 17:06
But, is there a pull-up somewhere in this signal path?
I can imagine that a broken pullup could look similar
No pull ups, I tried one just to see what happened, and no change. So looks like a blown output :(
Re: Falcon H-sync fault
Posted: 18 Oct 2018 15:06
by exxos
New Videl fitted and H-sync has a much better output now...
hsn.png
Unfortunately the odd sync issue persists :(
I have poked everything on the board, heated it up, frozen it to death, and cannot really find anything wrong anywhere. It acts like there is a bad connection somewhere.
I am going to put it down to another screwy issue by Atari. It could may well take a long time to trace as the fault is intermittent from a few seconds to a few minutes.
I am not going to spend any more time on this, as I have had this Falcon for months now for starters. Tracing these odd faults would likely take a epic amount of time which I do not have. Tracing these screwy faults is something I have spent a lot of time doing already on the STF/E already, I really don't want to start tracing these types of fault on Falcon's as well.
"Give it up as a bad job" as we used to say in my old workshop.
Re: Falcon H-sync fault
Posted: 20 Mar 2019 22:34
by exxos
This may have actually been cured... Please see this thread...