Subject: Amiga video

From: "TeoZ" <[email-masked]>
Date: Mon May 5 01:04:01 2003

Anybody have a cheap 390682-01 amiga to vga adapter or know where I can get
one?

I am trying to use a NEC 3DS monitor on my Amiga A1200 to free up my 1084
monitor for my A500 and C128. I tried using a custom cable from IEC but it
doesnt sync all the time (its just a wire thru while the silver amiga part has
a buffer chip inside).

---

From: Ethan Dicks <[email-masked]>
Date: Mon May 5 09:50:01 2003

--- TeoZ <[email-masked]> wrote:
> Anybody have a cheap 390682-01 amiga to vga adapter or know where I can
> get one?

You are referring to the 23-pin-to-HD-15 adapter with the C= logo on it?

I do not know of a source.
 
> monitor for my A500 and C128. I tried using a custom cable from IEC but
> it doesnt sync all the time (its just a wire thru while the silver amiga
> part has a buffer chip inside).

The buffer chip is an inverter chip.  I have built these before (with a
home-burned circuit board and everything).  You have to invert HSYNC
and VSYNC between the Amiga and some monitors (there were some high-end
monitors that could handle either positive _or_ negative sync signals).
ISTR it's just a 7404 of some flavor in the C= adapter.  If you wanted
to get really fancy, you can double-invert the signals, run the buffered
sync signals _and_ the inverted signals through a double-pole-double-
throw switch and make your monitor adapter selectable.

The Amiga video-out connector does provide +5 for powering external
devices (Genlocks, etc.), so that's one item you don't have to worry
about.  The pinouts for the 23-pin connector are in every Amiga manual
I've ever owned and I'm sure a Google search will turn them up, too.

-ethan
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