Re: Problem Using a Commodore 1084s Monitor on a IIgs

[Polymorph <polymorph69@hotmail.com>]

On Jan 22, 4:51 am, heuser.mar...@freenet.de wrote:
> Polymorph wrote:
>
> > Because of this I picked up a Commodore 1084s monitor off of eBay to
> > use as a replacement. I have tested the monitor with a DVD player and
> > the image produced was quite good, so I know the monitor is working.
>
> Via composite or via RGB?

Via composite only.

>
> > However, I wired up a cable as per the Apple II FAQ over the weekend
> > and had troubles getting the monitor to synch with the RGB signal. The
> > image just kept scrolling all over the place.
>
> This really sounds like a sync problem.

Thats what I reckon too...   :-)

>
> For a PAL monitor you don't need to do this.
>
> > Is there anything else I can try to get the image to synch?
>
> The standard way for a GS to connect to a PAL 1081/1084s
> (the 1081 has mono sound, while the 1084 is stereo) is to use
> its Euroscart input with its analog RGB leads.

There is apparently many different connections available for the 1084
monitors and unfortunately mine does not have the SCART adapter. I
wish it did as I already own a IIgs --> SCART adapter from
Vintageware. The 1084 monitor I have only has the D-9 RGB connector +
the usual composite sockets.

>
> Pin 3 ("composite sync") of the GS video output jack must be
> fed into the composite video input of the Euroscart connector
> (pin 20).

Well, as per the Apple II FAQ, I have the composite synch wired up to
the composite synch of the D-9 connector (from memory I think its pin
7).

> There is more to do with this type of connector - this page
> details the pin to pin connections:http://vintageware.orcon.net.nz/apple2/scart.html

I bought one of Vintageware's cables a couple of years ago which was
connected to the monitor that died. As the new monitor doesn't have
SCART, its been made redundant until I can fix the original monitor.

> Here you can download the PAL schematics of the 1081s which
> may or may not be of help (be cautious because of the differences!):http://rapidshare.de/files/38368884/Monitor_1081.zip.html
>
> I would try to connect pin 3 of the GS output to the composite
> input of your monitor.

Yep, did that. That is as per the Apple II FAQ.

> If this doesn't work it could be a "sync-on-green" problem but
> I'm not really familiar with this. I only wanted to throw this into
> the room so somebody else can jump into it (or discard it).

Any comments on the usage of a 75 Ohm resistor between composite synch
and ground? I think I will try this anyway, as Jeff Blakeney has a
pretty good rep around the traps and I'm sure he wouldn't have said
that if it were'nt necessary for him.   :-)

Thanks,
Mike