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

[Polymorph <polymorph69@hotmail.com>]

Answers below:

On Jan 22, 1:17 am, ferd...@gmx.de wrote:
> Is the image rolling up and down or left/right?

It seems to be rolling in both directions - but its hard to make out
for sure.

> If it is rolling up/down then you're lacking vertical sync. Otherwise
> you're lacking horizontal sync.
> Wiring Composite sync to Horizontal sync should give horizontal sync,
> but there may or may not be vertical sync. One thing to try would be
> to wire Composite sync to Horizontal AND vertical sync.
> If there is no horizontal sync you either have a bad sync connection
> (whereever... You didn't wire the DVD player to the DB9 input, did
> you?), or the sync level is too low (AFAIK Commodore used TTL sync,
> i.e. 3Vpp, but the IIgs uses only 0,7Vpp, however I'm not shure with
> this.)
> Does the 1084 have a switch to select analog or digital mode? If it
> has it should be set to analog so that the monitor takes sync from the
> composite sync input pin.

It does have a switch, and yes I have selected analog mode.

> > One thing I should note is that just about everywhere lists the 1084
> > monitors D-9 RGB connector as being female, however in the monitor I
> > have it is male. Consequently, my cable has a female D-9 socket. I
> > have made the assumption that the wiring would still be the same (i.e.
> > pin 1 mentioned in the A2 FAQ is pin 1 on my monitor). This seems to
> > be true as I do not think I would get the image that I am getting if
> > it were incorrect. It just seems to not be synching with the signal.
>
> You'll get that phenomenon if you just wired the sync incorrectly.
> There is a trick to figure out the pinout: Use a jumper wire to join
> the grounds of the Apple and the monitor. A good ground point is the
> metallic part of the D-Sub connector.
> Then start with the "red" signal and test every pin on the 1084 until
> you get a red display. Solder it to the connector
> Do the same with green (yellow display) and blue (white display).
> Now take the sync pin and tap through the pins until you get a stable
> display. Now turn the monitor of, and find the ground pins by
> measuring the resistance to the metallic part of the D-Sub. If it is
> <5 Ù, you have a ground.

OK, I'll give that a try. So nobody can vouch for the addition of a 75
Ohm resistor between composite synch and ground?

Thanks for your help.  :-)

I must admit, after reading all the descriptions floating around about
using 1084's with the IIgs I expected this to be a whole lot simpler.

cheers,
Mike