ToToTEK.COM

[Wai]

I have a Super Magic Drive to play my Sega Genesis games. It was working fine until two days ago. While I was playing Ecco the Dolphin, the screen froze. I thought it was nothing, so I turned everything off and went back to doing my homework (I had been playing for about two hours). Yesterday, I tried playing again. The Super Magic Drive seemed to have no problems reading and detecting the files on the floppy disk. However, once the countdown was complete, the TV simply showed a blank, black screen with no sound. The game did not load.

Here's some more details:
- I don't think it's the Genesis itself, because it has no problems playing cartridges without the Super Magic Drive.
- The TV is funtioning properly and play normal channels as per usual.
- The Super Magic Drive failed to play any floppy disk I put in it, so it shouldn't be any of the floppy disk's fault.
- Updated: I think it's the SMD800 alone that's causing problems.

Can some please guide me through fixing the Super Magic Drive? We bought it fresh from a store over a decade ago. If it was really dead, shouldn't it fail to turn on or even read the floppy disks? Did something come loose?

Any help will be greatly appreciated. I really hope my Super Magic Drive can be fixed.

[kyuusaku]

First try reseating the DRAM board, if that doesn't help check for continuity on the traces from the 74XX157 / 74XX257 chips to the DRAM board. If all of them are fine, probably either a 257 or 245 or the Altera EPLD chip is bad. Unfortunately, if you have a bad EPLD you're in trouble since you won't be able to replace it.

[Wai]

Thanks for your rapid reply, but what does the DRAM and the other chips that you mentioned look like, and whereabouts are they? Could you label them on a photo for me? I'm not familiar with playing with that kind of stuff hehehe.

And I just want to thank you again for your help. I was really worried that I'd never be able to play my favourite Genesis games again (I'm not too fond of playing ROMs on my computer).

[CrackLtd]

Just open the SMD800 (see 4 screws on the downside) remove the cover and you can check the printed circuit board. Your unit should something look like this: http://www.supermagi.com/pfs.php?m=view&v=1-super_magic_drive_mobo_a.jpg Unplug that little daughterboard maybe clean the pins a bit and attach it again. Also once you have opened the unit check the battery. Unfortunately it can happen the battery in the unit leaks and destroys traces around it. If so, remove the battery and ring through the traces with a multimeter to see if they have been hurt. What else you can do? If you have propper tools you can plug and unplug any of the chips which have sockets. Maybe just a bad pin connection. Anyways good luck! If your SMD800 is broken it will be hard to get replacement. But Genesis Cartridges are cheap nowadays, maybe buy Dolphin as an original? lol!

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[Wai]

An update from me:

I managed to single out the SMD800 itself as being the problem. The Genesis is fine, since it can play cartridges. I tried playing the Sonic 3 cartridge with the SMD800 attached, but it failed to work (which strongly suggests that the floppy drive is fine).

Strange enough, after securing some of the cables and plugs to the Genesis and blowing some dust off, the SMD800 occasionally managed to play some games. The simple ones tended to load fine, but the ones with more detailed or complex graphics (such as Ecco the Dolphin) would have some glitches (like running into imaginary barriers and getting stuck in walls). Otherwise, the games failed to load.

We bought the Genesis along with the SMD800 in 1992, I think (so it wasn't older than I am). I guess lasting for an amazing 16 years is quite an achievement lol. To me, they're one of my most valuable possessions.

I'll look into fixing the circuit components later tonight. I have to do some homework.

Once again, thanks for your help!

[Wai]

I checked the battery (the dark blue thingy that says VARTA), and I'm sure it's one of the culprits. It has leaked some solidified stuff out of it. I have carefully removed as much of that stuff as I could. What can I replace the battery with? I've been playing my games with floppies, so if I replace the battery, would it affect anything? I don't remember storing anything in the memory.

Also, I think the yucky stuff that the battery leaked out may have affected R7 (there's some teal-coloured stuff coating the metal parts of it). I scraped most of it off, and luckily it hasn't eaten through the wire.

I also secured the daughterboard more firmly to the motherboard (one side was just a tad little loose).

I just tried loading a few of the floppies, but the games didn't load.

[kyuusaku]

If you don't play any games with battery backed SRAM, you won't miss the battery.

[Wai]

So what exactly is the battery for, besides memory? I just searched and found this topic:
http://www.tototek.com/phpBB2/viewtopic.php?p=6508

I am willing to purchase the following battery:
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=126720&pa=126720PS
However, is it also available in Australian stores such as Big W, Harvey Norman etc?

[madman]

As Kyuusaku already told you, the battery only affects games with battery backed SRAM.

[Wai]

So can the SMD800 function altogether without the battery? If it doesn't need the battery, and I replace it with a new one, wouldn't it will still fail to load any games?

[CrackLtd]

No, the battery change will not solve your loading problems. If the unit cant play games now, it wont after the battery change. For what is the battery at all? Well, lets say you play a normal (original cartridge) game, like a big adventure rpg game or so. Now you play a while then you want to quit. When turning off the console now you will lose all your progress in the game. So most games offer the possibility to save your game into the cartridge, so you can turn off your Genesis (same goes for snes) and continue to play the game the next day right from the point you left the game. Now, when you use a backup system like the SMD800 you have no original cartridge where the program could put the save-info to. For this the backup system has its own save ram, or better called: SRAM. Of course this ram needs power to keep its information even after the console (and so the backup system) is cut off the main power. Here is where the battery comes in. It provides the SRAM with power so it can keep all the information. So, if you change the battery it will not affect anything else then the SRAM, so it will not solve the other problems you may have with your system.

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[Wai]

Oh bummer, so the battery isn't the culprit then. So I'll need to check the other components that you mentioned then.

How do I remove the leaking old battery from the SMD800? Do I just pull it out? The only circuits I've ever played with are those on circuit breadboards. If I remove the old battery, but I don't replace it, the SMD800 will continue functioning (i.e. the circuit isn't broken), just without a place to store the SRAM?

[madman]

You'll need to unsolder the battery to remove it.

[Wai]

I'm not a good photographer, but I think these might help. The areas where I think the battery leak has caused some damage are circled. I'll number the images from 1 to 4, from left to right.



1. Top view of the SMD800 motherboard.
2. The underside of the daughterboard, which I think has taken some nasty damage from the battery leak.
3. I'm not sure if that's the battery's fault, but there seems to be a bit of corrosion there.
4. Resistor 7 (R7) has been circled, and parts of the wire have partially corroded (but not eaten away such that the wire is disconnected). The golden coloured foil (or wires, I don't know what they are) may have been corroded by the battery leak.

I don't have a multimeter at home. I might have to borrow one from my school.

[Xenepp]

Sorry to say but that looks in need of a drastic cleanup. The acid may have (quite likely) destroyed some of the smaller traces on the PCB there.

That said, I'm 99% sure your main problem, or why games won't load, is the damage to the DRAM PCB.

I'd say for now, get that battery the hell out of there and on your RAM card, use something lightly abrasive, such as fine sandpaper or a fiberglass pencil to remove as much of the corrosion as possible. It might not have gone right through the copper layer. If it has, which I suspect is your problem, you'll need to solder a jumper wire as illustrated below:

<a href="http://img252.imageshack.us/my.php?image=smd03zt2ky6.jpg" target="_blank"><img src="http://img252.imageshack.us/img252/8293/smd03zt2ky6.th.jpg" border="0" alt="Free Image Hosting at www.ImageShack.us" /></a><br /><br /><a href="http://img604.imageshack.us/content.php?page=blogpost&files=img252/8293/smd03zt2ky6.jpg" title="QuickPost"><img src="http://imageshack.us/img/butansn.png" alt="QuickPost" border="0"></a> Quickpost this image to Myspace, Digg, Facebook, and others!

Give it a go, if it works you will still need to clean up the main PC board asap, but it looks like it might be quite a job if you don't really know what your doing.

I actually would not use it again until I'd cleaned the PCB and replaced any capacitors or resistors that got caught in the corrosion.

-Joel