Matrox G400 video card repair

[Catherine]

Hi,
I have a Matrox G400 MAX video card that got two little surface mount
condensers ripped off by accident and it gives little video defects but
otherwise still works great. I would need the values of C152 and C153. I
can make the repair myself but I can't find a schematic or anything about
it. Does anyone have more information?

 

[Aries Quitex]

When you say it delivers little graphical errors it could be very well that
it are the high/low-pass filter-capacitors from the RGB-out.

If noone else can help you, I would suggest you try to track down if these
cap's are in the RGB output-stages, and then search for the complementary
caps.
Alternatively you could try to find out which purpose they might have had.
When they were there to stabilize the voltage for the output-drivers or any
other component, you could same as well take "just a large enough" value,
that depends on the other large caps on the board.

 

[Catherine]

When you say it delivers little graphical errors it could be very well that
it are the high/low-pass filter-capacitors from the RGB-out.

If noone else can help you, I would suggest you try to track down if these
cap's are in the RGB output-stages, and then search for the complementary
caps.
Alternatively you could try to find out which purpose they might have had.
When they were there to stabilize the voltage for the output-drivers or any
other component, you could same as well take "just a large enough" value,
that depends on the other large caps on the board.

Catherine wrote:

The defects are digital in nature. Text mode is mostly unreadable because
caracters get substituted by garbage, graphics are generaly fine but there
is always vertical streaks spaced by about 1 centimetres on a 15 inch
screen in some part of them, it depends on the colors it seems, one
strange thing is the cursor is never affected even when moved over areas
that have defects. The two condensers are at the botom of the board near
the AGP card edge connector and the GPU. I know I can try values and test
from there but I would prefer to get the right value right away that way I
have less chances of damaging if further by soldering and desoldering.

 

[JURB6006]

In this case you might just want to put in a couple of say 22uF/16V and see if
it fixes it. The only engineering reason to use larger caps has to do with
powering down, i.e. what drops first. The frequencies are so high that a 100uF
does little if anything for it.

What's more too large a value may cause excessive inrush at startup and damage
something.

If you really want to try and get the right values you might try to find one
for sale with a picture, like on eBay, then save and enhance/enlarge the image.
Acually it's probably not that critical, and if you're worried about soldering,
just use regular caps with the leads cut down. That way if it doesn't work you
can change them again more easily.

JURB

 

[Rick]

Hi,
I have a Matrox G400 MAX video card that got two little surface mount
condensers ripped off by accident and it gives little video defects but
otherwise still works great. I would need the values of C152 and C153. I
can make the repair myself but I can't find a schematic or anything about
it. Does anyone have more information?

I just looked at my G400 Max and C152 appears to be
the same part as C149 (to the left about 3/8", and C153
the same part as C151 (immediately to the left of C153).

As for values, I can't help you there. C152 is tan while
C153 is a very dark brown.

Rick