Emile, I now have my PC VGA (Wearnes VGA) running on my 660av,
using an adapter similar to the one you've described.
The mode to use is VGA/SVGA (640x480/800x600@60Hz) - SEPARATE SYNC
(On my no-name adapter which has a 10 position dip-switch this is 2367=on)
[same as yours]
If your adapter or monitor are different check these out:

660av/840av: Multiple Scan Startup Resolution
http://www.sims.berkeley.edu/~jwang/cgi/av-faq/Hardware/660av%20&%20840av/Mu
ltiple%20Scan%20Startup%20Resolution
"(Note: The initial "sensing" of the monitor happens before the file system
is around, so it cannot be patched). "

Technical Note HW26 - Macintosh Quadra Built-In Video
http://developer.apple.com/technotes/hw/hw_26.html
(includes ascii wiring diagram for DB15-HD15 adapter)

Marcus.

ps. replacing my battery helped :))  (ok it wasn't there in the first
place!:)
pps. what sort of PC monitor are you using?

> Hi all (Marcus, Oliver and others)
>
> This morning, I had to connect a PC Monitor to a Macintosh for my nephew
(son of
> my brother) this morning.
>
> He brough a PC/Macintosh video adaptator and come with an old PC monitor.
>
> The video adaptor came with a piece of paper that someone can call it
> "Intructions"... [ :( ]
>
> The video adaptor have some On / Off interruptor that the user have to put
on
> some place to get some video.. (not clear ? Normal, it waasn't clear on
the
> "Instructions" card !)
>
> My nephew told me he cannot get any video...
>
> I use a Quadra 700 (...) for the tests.
>
> The video adaptor had no brand (and was sold on FNAC store in France)
>
>
> Back to what I've done and the results...
> -----------------------------------------
>
> I set the On / Off interruptors using the instructions for NORMAL and
VGA/SVGA.
>
> In the interruptors I used, the On / Off were:
> On:   2,3,6,7
> Off:  All other interruptors...
>
> I power on the PC Monitor, then the Quadra 700.
>
> The used system software was MacOS FU-8 (or FU-8.1 ?)
>
> Because the battery on my Quadra 700 was down, I boot on black and white
and set
> the colors back using the Monitor Control Panel.
>
> When I was there, I click on an option button (I don't know the US name of
that
> button in the Monitor Control Panel, but it is really easy to find it).
>
> The choices were: 640 * 480 or 800 * 600. I stay on the former. I do not
change
> the Gamma or another choice.
>
> After some talks with my nephew, I show him the 800 * 600 mode and set the
mode
> back to 640 * 480 telling him he now knows how to change it.
>
>
> Nota:
> If you make some testings, be sure to reboot after making the changes in
the
> video adaptor (Macintosh ROM test the presence of a monitor at early boot
time).
>
>
>
> Please, note that using the 4, 7 and 10 pins (with metal paper click or
diode)
> on the Macintosh video port can force Macintosh to VGA Mode... BUT a
problem
> remains with the different size of the connectors (PC / Mac use different
size
> and kind of video connectors).
>
>
> If some people need more information, please ask me (on the list or to me
> directly) and wait some days for a complete answer (as complete as I
can...).
>
> I need some days because I have to search very old (MacWrite files) Apple
> TechNotes, wait to allow time for people to read this and ask more answer.
>
> Last note: some years ago I build a Macintosh video to European TV Scart
to
> watch on my TV screen the Macintosh video: as PAL, but Quadra 700 can also
send
> NTSC video signals. Other Macintosh can also generate other video signal
than
> just 640 * 480...  ;-)
>