Wobbly screen with my Genesis model 1

[Sublevel]

I got a model 1 Genesis(with TMSS), and everytime i start the console the screen gets all twitchy. Check this clip, most noticeable towards the end:
http://www.youtube.com/watch?v=hOnQHDumMSA

When i tap the top of the console, it stops. Can someone understand what causes this? It's not the power cables, and it's not the cartridge slot.

Tapping the top works everytime, although it's pretty annoying.
I really dont want to get rid of this model, the sound is really great.

Anyone?

[sega fan]

I don't know if that's a problem with your Genesis. It might be an issue with your display.

Flatscreen TVs don't handle retro games very well and "wobbly video output" is one of the problems I ran into when I tried playing old games on my flatscreen HDTV.

[Jorge Nuno]

Seems like an intermitent connection.

Youre using RGB? It seems so.

[sega fan]

Seems like an intermitent connection.

Youre using RGB? It seems so.

Switch to composite cables and it might help. Your image quality won't be pixel crisp but the wobble will go away.

If the problem persists, the only other advice I can give is to switch televisions. Tube televisions are preferable when it comes to older consoles.

[Sublevel]

I forgot to mention, i have several retro consoles hooked up to this display(LCD TV).
SNES, NES, PC Engine and Genesis. I only get this issue with the Genesis. The other works great with no problems whatsoever. All of my consoles except NES is hooked up with RGB-cables. All consoles are NTSC versions.

I tested the powersupply and RGB-cables with another Genesis and that worked flawlessly. Too bad that one had a broken headphone jack

Any idéa what might be causing this problem and what to do?

[Jorge Nuno]

Well that really seems like a broken connection as a said above.
It's either the sync, the video or the ground. It could be the connector or between the video encoder and the connector.

It could also be the connector itself being dirty, but I think it's unusual.

[roguetrip]

Does it happen with all the games or mainly M.U.S.H.A? If you stick like a piece of cardboard or something in front or behind the cartridge while inserted (forcing the cart forward or backwards a bit to make contact better) does it get better. This might show it is a connection/connector issue.

I'd start by cleaning the cartridge and the connector in the genesis and see how that goes. Then I'd see if you need to reflow any solder joints for the main connectors (A/V and Power connectors) in the genesis. Maybe even needs joints redone on the main connector itself.

When I bought my genesis (model 2) years ago, I found that I'd lose power every once in awhile and before I knew how to solder I just stuck a bunch of tapped up washers on top of the power connector to force it down from wiggling. When I pulled the system out of its deep slumber a little over a year ago I re-flowed it and the A/V connector fixing the issue properly.

I also cleaned the slot connector back then and always clean any game I buy before it touches the system to help keep contamination down. I recently put in Lightning Force but had to re-seat it a few times before it would even read properly so just cleaning it doesn't eliminate deformed/worn contacts . There is no way in heck I'm replacing that connector though!

[Sublevel]

Thanks for the replies.

I'll take a picture of the console with the case open, maybe you guys can see directly if something is wrong. Then i will try to clean it, but i really dont know where to look except for the cartridge connector..

I get this problem with every game i play, not just M.U.S.H.A. I keep them all very clean, so i guess we can count that one out. It's not an issue with the games, it's most definitely the console.

[Sublevel]

Well that really seems like a broken connection as a said above.
It's either the sync, the video or the ground. It could be the connector or between the video encoder and the connector.

It could also be the connector itself being dirty, but I think it's unusual.

I dont really know anything about this. If i upload a pic of the motherboard tonight, maybe you can mark these portions out?

[Sublevel]

This is what my motherboard looks like, if it can be of any help:

[Jorge Nuno]

Please remove the aluminium heatsink and tell me/take a pic where the thick red wire goes.
I think that little circuit is doing something wierd

[fr@ser]

Please remove the aluminium heatsink and tell me/take a pic where the thick red wire goes.
I think that little circuit is doing something wierd

I've seen this on something else ,i think it was on some arcade machine forum.Also i had a problem like this with a few consoles which were connected to my multi scart switcher .

If i left my playstation connected to the scart switcher (with no power to the console)and had my sega master system or mega drive in use,i would get the loss off sync .just unplugging the other console's scart lead corrected the loss of sync instantly .

One more thing i think it could be with,that little pcb board you have,it may be creating a closed circuit by touching something on your mega drive .(judging by your tapping of the console and the actions shown).

That little pcb really should be insulated with tape at least,to stop any short circuits.