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VGA Switch Design

M

Mio

Jan 1, 1970
0
Hello,

I've been trying to follow the schematic at
http://hyper.sunjapan.com.cn/~hz/PIC/vga-switch/index.html

and build my own VGA switch. I've got a projector that takes both
component and VGA input on the same Dsub15 plug. I use a mechanical
switch currently, which works, but it's a crappy solution, introduces
noise, and sometimes has to be hit to work properly. Mechanical
switches suck, and I wanted to go solid state with it.

As the MAX465 is not available anymore, I redid it using a MAX4026
(It's mislabeled as MA4026 in my schematic), adjusting the pinout
obviously, but when I power it up, nothing happens. Directly from my
laptop to a monitor works, but when I put this in between, nothing
happens. I don't have a component device on my right now (The
projector is being repaired.) to test it with, and I don't have access
to a scope right now (Though I will next week, and will be testing to
see which signal(s) aren't being properly routed.), so I thought I'd
ask here first. The only thing I really tested was that the MAX660 is
properly generating the -5V, which it is.

I wasn't entirely sure what to do with the feedback pin on the 4026. I
grounded it directly, but perhaps that wasn't the right thing to do
with it? Floating made no difference.

The only thing not shown on this schematic is that there are 0.1uF
ceramic caps in various places. One under the chip that only uses the
0/5 supply, and 2 under each that takes -5/+5.

http://www.hid.com/dan/selectee.pdf

Thanks,
Dan
 
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