Jaleco Mega System 32 - Graphic fault.

[pcb_revival]

One of the lesser popular cartridge formats is the Jaleco MegaSystem 32 around ten games were released in its liftime.

I have seen two versions of the motherboard MB-93140 and MB-93140A both have a huge amount jumper points totaling 40.

I have five MB-93140A motherboards and they all have JP12 and JP15 connected.



The one MB-93140 I own does not have the connection.


Anyways the problem appears worse dependent on which game is used.

Tetris Plus cart shows virtually no problem only flickering on "Stage Clear" text.

The Game Paradise however as the intro messed up and as slight corruption in game.



The problem motherboard (a MB-93140A) as one difference to the others - JP30 is soldered over - all the other motherboards this jumper is clean although the single MB-93140 had the jumper soldered at one point but this was removed by someone.

I have seen this graphic glitch before with the same game over at neogeo.com so is it common and is there a fix.

[Dave_K.]

These motherboards must be quite fragile, as I had one suddenly stop working for me. It boots up showing nothing but green and white blinking dots now. I bought a second one that works fine. Both are the MB-93140A and both have the same jumper connection as in your picture. I've never seen that graphic corruption before though.

[quoth09]

I have currently the same issue as Dave_K. right now.

No answer on the issue with the bugs, sounds like graphics CPU has broken trace on one of it's lines possibly?

[IronGiant]

It's quite possible that one or more pins on one or more of the surface mounted chips has lifted. Not saying it is that, it's just one of the first things that I'd personally check have repaired many boards with surface mount problems.

[pcb_revival]

The affected mobo works nearly without fault with Tetris Plus so it not really a problem and they are cheap enough to get a replacement sometime.

[Dave_K.]

Well I'll be damned! I hate to admit this stupidity, but today I figured out why one of my Mega 32 mobo's was booting up with blinking green dots. Apparently I put the cart in upside down! Kinda strange there is no keying or orientation indicators to make sure you don't do that, but it fits just fine either way. Thankfully, this does not damage the mobo or the cart, since flipping it around and now its working like a charm.

[PC Engine Fan X!]

Yep, it pays off to make sure your carts are oriented in the proper direction on a typical motherboard or else things might not work 100%. Interesting that Jaleco doesn't mention which way it's Mega32 carts should be facing for proper boot-up...it's through trial & error does one find out the hard way.

PC Engine Fan X! ^_~

[pcb_revival]

The correct way to locate a cartridge is described in some of the manuals - Tetris Plus for example.

But yeah I must say when I first got the system and saw contradictory images online that showed a cart positioned both ways it was confusing.