Falcon H-sync fault

[exxos]

Never seen this before...






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

[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:

[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

[exxos]

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 :(

[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.

[exxos]

This may have actually been cured... Please see this thread...

https://www.exxosforum.co.uk/forum/viewt ... =17&t=1698