Problem with VGA on Falcon

[fidzen]

Hi all.

I have a Falcon with CT63 and Supervidel.
It has been working great until yesterday.
When I boot the computer with the monitor connected to the SV, I get picture and all is fine.
But when I connect my monitor to the VGA out on the Falcon and boot, I get a black screen.
It seems like the computer still boots, but without picture. Same in 030 and 060 mode.
Another thing I have noticed lately is when I run compability mode on my SV, I sometimes get
a weird picture all bugged out. But sometimes it works.
So something is wrong with my Falcon, but I don't know where to start looking.

Thanks in advance.

[jvas]

Is your NVRAM ok?

[fidzen]

Is your NVRAM ok?

I can reset the NVRAM and change settings, and it remembers the settings.
So I guess it's okay. I changed the NVRAM chip maybe 2 years ago.

[christos]

Is it set for VGA or is it set for TV/RGB?

[fidzen]

Is it set for VGA or is it set for TV/RGB?

It's set to VGA.

[fidzen]

Something I also discovered is that when I start in 060 mode and the screen connected to the SV.
If I then have the cable connected to the SV that is soldered to some points on the main board,
I get weird frequency on the screen. I can get 58Hz, 62,5Hz or 72,5Hz. If I disconnect this cable
from the SV I always get a stable 60Hz when booting. So it seems like the main boards Videl and
clocks provide unstable frequency. I tested to replace the 25MHz crystal but no improvement.
Could it be so bad that the Videl chip is broken?
As I said first, this is a problem that I have seen more and more of lately. So something has
been bad for some time, but now it's broken somehow.

[fidzen]

Have replaced both the crystal U41 and the NVRAM, but still no difference.
What components are used to produce the VGA-signal in the Falcon?
I don't want to replace the videl chip if I don't have to (very difficult soldering).

[mikro]

What happens if you remove the SV altogether?

[fidzen]

What happens if you remove the SV altogether?

Black screen in both 030 and 060 mode. The computer boots it seems, but with a black screen.

[mikro]

Then you have a winner, there's surely something wrong with the original video subsystem. Hard to debug, yes.

[fidzen]

I received a new Videl chip from Best Electronics today and soldered it in.
The expectations was not very high when I turned the Falcon on, as I didn't
really thought it was that easy. But it was! Now it works like a charm again.

[dhedberg]

Great job! Another Falcon rescued!

[mikro]

Are you sure the problem wasn't just some loose connection to the Videl chip? It's hard to believe that the chip itself would break. But who knows... glad that it works!