Using CompositeVideo as Sync on 1084 without a LM1881 (Megadrive on Steroids)

Hi!

Just wanted to share my success at building my very first RGB cable / mod with you guys. 'cause you are my favourite forum right now. :thumbsup:

I finally got RGB working. :-0
And my girl is playing Truxton for 3 hours now. :dance:

This is a quote from nfggames.com - thread http://nfggames.com/forum2/index.php?topic=3387.0 - maybe it is of interest to you too:

RGB ... Megadrive ... Truxton ... ray:

 

So this is an alternative to building an LM1881 circuit? I'm presuming it was a sync issue.

 

You are very right. I had issues with sync, and it replaces the LM1881 circuit :nod:

I did not have a LM1881, but I had a spare, short cable. :thumbsup:

ninn

 

So this was only to fix sync?

Cos I thought a PAL MD output RGB as standard???...I damn hope so as I'm performing a 50/60 and region mod on one tomorrow (if it turns up...damn Royal Mail) and I already have the parts for that. Don't want to buy anymore.

 

All Megadrives will output RGB with the right cable. I think the first two Genesis do but Genesis 3 doesn't.

You won't have any trouble with that mod, anyway - it's nice and simple.

 

After my exploding Supergun experience I'm nervous about all soldering, but it looks pretty straight forward...

I have all the bits and a shiny new Stereo RGB cable but no console yet :shrug:

In two minds as to where to put the switches (they're chrome toggle not sliders) seeing as it's a MD1, I was thinking of putting them to the left of the volume slider, as additions to the kinda control deck area thing it's got going on but I know there's quite a bit of shielding underneath this...problem?

 

There's no harm in cutting away a bit of the shielding. I did for mine.

I went with sliders over toggle switches as I was concerned the latter would stick out and potentially get knocked and damaged. Saying that if I'd have had toggles and no sliders I'd have used the toggles anyway I'd probably put them in the dip in the case near the power switch on the MD1, if there's room.

It is as straightforward as it looks in the instructions, anyway, so honestly you'll be fine. The soldering points are nice and easy (at least compared to most console mods I'm used to)

 

... .actually, the thread's topic is quite missleading ... better be using "Using CompositeVideo as Sync on 1084 without a LM1881" - with "Megadrive on Steroids" as a Sub. ^^

Nevermind.

This was a quite easy (except the fact that you had to dismantle the monitor completely) and very effictive hack on how to use compvideo as the sync for the 1084. I had no luck on syncing the Megadrive's picture with the default RGB-output of the Megadrive. This one solved it instantly.

I will have to do a region- and 50/60hz-mod too. I already got the dip-switches and will happily solder them into place the next days. I am still unsure where to put them, too... I am thinking about the side next to the reset/volume buttons, or just the back side. will keep you updated with pictures once I built it.

... but ... just to say it again: RGB is god-like.

 

... looks like the hack generates problems with 60hz rgb-signals ...



notice the very top of the picture - it is bent to the right.

.... :crying:


A solution is - hopefully - coming to that thead http://nfggames.com/forum2/index.php?topic=4435.msg29775 in a near future.

Just wanted to tell you that it is not that easy to replace the LM1881 with a spare cable. OH:

 

x

 

ok ... I will add those caps to color and sync today.

 

The Caps & resistors made the wobble worse OH:

 

Try just caps/just resistors.

 

From the picture the horizontal PLL is having trouble locking, probably due to vertical interference, that happens when you jump signal processing stages.