MegaDrive 1 CXA1645 mod

Hmm, odd. Kind of wavy or something. Personally I'm trying to hold out for a MD (as opposed to Genesis!) lacking that message... Hard to find someone who'd let one go.

 

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I have not such a mobo, in fact I have a crappy Asia model.
I'am about to buy a true Japanese Megadrive but one question first:
What kind of Megadrive do you have Druid II, is this pics taken from yours?

 

I have a PAL MD2 Lum but from what I've seen you look like you want a MD1 without TMSS.

Though mine does have a 50/60hz switch. Previous owner drilled a hole for a region switch but botched the solder job lifting a pin from the requisite chip which I fixed after removing silicon from theIC casing....

Love "hobbyists".

 

I recently got a few mega drives. 2 have the hd text and could possibly be what he wants.

I will take a look on the weekend

 

Tried to remove pin 6 from chips but still ahd jailbars...:crying:

 

And it does! Completely remove the jailsbars for me. :thumbsup:
I made a switch to see the result, and it's obvious.
Resolder after that the pin 6 and it was the same perfect result.

Thanks (again) Link83.

 

Yeah I'm after the mega drive look. Check for any dead hd text models unfeasible to repair. If necessary just a pal case and other aesthetic components different than North American, that can fit onto my usa board 100% would do. It'll save on postage if I don't need all the system internals I won't see when playing anyway.

 

Is this MegaDrive 1 or 2?

 

HAA2510 Asian Megadrive 1.

 

Damn why did I miss this in the first place. Just did this and it drastically improves the picture. I should probably test it a bit more but I think it's safe to say that it's much better than my RGB amp

Thanks Udan and Link83!

I made a simple switch too so I can do some screenshots showing the difference with my XRGB-3.

I'll upload them in a little while.

 

Excellent.

 

With pin 50 connected:


Without:


It's not PERFECT as you can see. There is still a hint of jailbars to see. But add scanlines to that and it's pretty great.

Perhaps it could be futher improved? What would happen if we connected pin 50 to GND?

 

Have you tried Megadrive 2?

 

I don't think I have ever seen jailbars on MegaDrive 2's.

 

very little. The picture improvement is because the signal from pin 50 is not running down the trace right next to the blue channel trace.

 

The colour looks better with the 'jailbars'.

 

In that case the interference must take place right before the CXA1145. I tried swapping the green and blue colors at this point on the bottom of the motherboard:


- And the jailbars completely disappeared from the blue color and appeared in all the greens instead. I swapped the blue and green at the AV out too of course. And I should mention that this picture was taken AFTER I restored the original traces, but you get the point.

I noticed the slight difference in color too when I looked at the two screenshots yesterday. However I did not notice any difference on my TV when switching pin 50 on and off.

 

You need your eyes tested.

 

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