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.
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.
Last edited by Lum; 10-14-2011 at 02:13 AM.
I have picture like that on one of my Saturns, one that uses a 3rd party replacement and not an actual cxa1645.
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I have not such a mobo, in fact I have a crappy Asia model.Originally Posted by Druid II
Desolder the cap directly below the text "C28". Watch out so you don't end up tearing out the connections, though, since you have to heat up both ends while removing the cap. If you do end up tearing the connection out, you'll have to manually reconnect the signal from R23 to the cxa1145 pin6 - in case you want to undo this.
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".
http://www.assemblergames.com/forums...ad.php?t=31524
My feedback thread, since it seems somewhat difficult for people to find.
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.
Last edited by Lum; 10-17-2011 at 07:43 PM.
Is this MegaDrive 1 or 2?
Konsolkongen
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 :D
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.
Konsolkongen
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?
Last edited by Bearking; 10-19-2011 at 08:15 PM.
Konsolkongen
Have you tried Megadrive 2?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?
I don't think I have ever seen jailbars on MegaDrive 2's.
Konsolkongen
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.
Last edited by Bearking; 10-20-2011 at 04:34 AM.
Konsolkongen
Late reply,
No, that picture is not mine. They are from here:
http://arcade.ym2149.com/megadrive/
But now that I've finally taken pics of my MD, it turns out that it uses the exact same motherboard as the one on that picture. All the serials on those pictures match the one on my Megadrive.
Though my machine could possibly be a bootleg since it has no serial stickers or any copyright notices on the bottom, nor even any trace that the stickers were removed. The plastic upper cover was also marked to be made in 1995 January (did they make MD1s that late?). Regardless that should not make a difference, most chips show the same markings so it's not some electrically identical knockoff (it has a NEC Z80 and a Hitachi 68k, the ram chips are different, but the sega/yamaha/sony chips are identical).
I've also rechecked for jailbars, and some do remain even with C28 removed. However they are extremely minimal, I had to max out the contrast and watch a pure blue background from 2 inch away on a 42" plasma screen to see them. I did not manage to make a photo on which they are visible.
If I could've made digital captures of the signal, they probably would've looked the same as the ones Bearking posted above.
Last edited by Druid II; 10-22-2011 at 07:23 PM.
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