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 (3.67 KiB) Viewed 5150 times
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 (3.44 KiB) Viewed 5144 times
Faulty machine.
v1.png (3.29 KiB) Viewed 5144 times
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 (3.34 KiB) Viewed 4887 times
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...