Problems running RGB SCART on Commodore 1084S Monitor

[duddyroar]

I've had a torrid time trying to get my retro consoles to run on my dusty old 1084S.

I'm trying to run 60hz games consoles (Mega Drive, Neo Geo AES, SNES, etc) through the monitor, and I'm getting a decent, bright colourful image but the picture rolls like hell.

Behold:

[ Show youtube player ]

I'm using one of these to connect the SCART to the monitor, which is probably the cause of my problem as it's not been created specifically for this monitor.

Can anyone help?

BTW, this is my monitor (and yes it has been cleaned since these images were snapped):

[s2325]

I have same monitor but I can not see on your photo small knobs at the back. They're also for V-Hold.

[duddyroar]

There are knobs on the front for V and H hold, and a nob on the back (next to the RGB socket) that seems to control that too. Is it worth tinkering with those?

[s2325]

Yes, V = vertical.

[duddyroar]

I tried adjusting the ones on the front and it made the picture a little better, but not much.

The one on the back requires me to insert a screwdriver, not tried that one.

[s2325]

Maybe be careful with that one.

[duddyroar]

Actually the one on the back is marked 'V HEIGHT' so I'm not sure that is going to solve the problem...

[duddyroar]

Does anyone have the pinouts for this monitor type?

[8bitbubsy]

Seems to be an issue in syncing the scanlines vertically...
What kind of system did you connect to the adapter?

[duddyroar]

I've tried a Mega Drive and Neo Geo AES, both outputting 60hz RGB signals. Both times the picture rolls like in the video.

[pandy71]

It is vertical or diagonal roll? If vertical - issue is simple, if diagonal - more problematic to solve. for NTSC not only V-Sync is different (60 instead 50 Hz) but also H-Sync (15750 vs 15625Hz)

[duddyroar]

Check out the youtube video link in my opening post - it looks diagonal to me

[thgill]

You're not using composite video for your sync are you? Cause if you are you may need to use a LM1881 sync stripper to extract out the composite sync from the composite video signal.

I know some Scart cables (perhaps all of them?) are wired to use composite video as the sync for RGB. I am guessing the 1084 doesn't like that whilst your regular euro TV's handle that ok.

[pandy71]

Originally Posted by duddyroar

Check out the youtube video link in my opening post - it looks diagonal to me

Maybe bad caps? - Your roll is very irregular - looks like TDA2595 can't lock to sync pulses - but - im not sure that PAL1084 is able to work with real NTSC (not like in Amiga quasi NTSC)

From datasheet TDA2595 looks like NTSC should be possible.

Originally Posted by thgill

You're not using composite video for your sync are you? Cause if you are you may need to use a LM1881 sync stripper to extract out the composite sync from the composite video signal.

IMO 1084 internally use composite sync so H and V must be combined before they are fed to TDA2595/TDA2653

[8bitbubsy]

Just a note:
This RGB mod works fine on my 1084S-P1, I hook up composite sync, R, G and B + ground.
I can do PAL 50Hz/NTSC 60Hz no problem... SNES, N64, PSX, PS2, GC etc!

[duddyroar]

Is the 1084S-P1 different from ther 1084S-D?

[pandy71]

Originally Posted by duddyroar

Is the 1084S-P1 different from ther 1084S-D?

can be...

[rockape]

Originally Posted by s2325

I have same monitor but I can not see on your photo small knobs at the back. They're also for V-Hold.

Hi,

See The Big Book of Amiga Hadware:

http://www.bboah.com/index.php?sid=1...865&artlang=en

LINK = Monitors

"1084 Sub-Models

The 1084 and its variants (1084S, 1084ST, 1084S-P, 1084-P, 1084S-P2, 1084-D, 1084S-D) are all 15.75 kHz monitors.

They do not handle AGA "double" screenmodes, nor will they display the deinterlaced output from the A2320 Amber board or the motherboard deinterlaced output on an A3000.

However, they will show all normal 15.75 kHz displays, and many (most? all?) of the 1084 versions have a separate input for composite video.

The 1084 is a usually a variation of the Philips CM8833 monitor; the 1084S-D was made by Daewoo (as was the 1084D, probably). The display tubes used in these monitors were made by Orion, Toshiba, Hitachi, and Samsung.

At one time or another, every possible permutation of connectors and video capabilities on the 1084 seems to have been reached, so don't be surprised if your 1084 has some bizarre combination of connectors and specifications.


The Pin Outs are on the page as well.


Regards, Michael

aka rockape

[duddyroar]

Thanks! That doesn't mean much to me (I'm a bit of a dunce when it comes to this kind of thing), but perhaps that information will be useful to someone else who can help?

In the meantime, I've been tinkering around a bit more:

[ Show youtube player ]

That video shows me attempting to play a Mega Drive game. The signal is 50hz and as you can see when I fiddle with the V-HOLD dial I can get the picture to stabilise a little, but still not enough to be playable.

[pandy71]

Ok, i see, it looks like sync depend from content of the video - probably cap responsible for DC restore, maybe separation caps are to old/bad/wrong capacity after years - this is first what i have in mind - replace all caps in signal path, also fix (resolder) all joints - maybe some of them can be cold...