Super Magic Drive research thread

Ask anything your want about Megadrive/Genesis programming.

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Koji
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Post by Koji » Thu Apr 21, 2011 7:28 pm

Got a hold of a FFE floppy Drive to finally test my SMD.
The FDD tries to read the floppys with little success, and after that all I get is a "DISK ERROR" on screen.
I took the actual drive apart and tested it on my PC and works fine so, the SMD must be at fault or, is there any disk incompatibilities for SMD's V-1 revisons?. Any ideas?.

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Post by KanedaFr » Wed Apr 27, 2011 8:56 am

It's exactly what I have right now...
I suspect a problem in the voltage regulator....

I haven't a PC PSU available, else I would have connected the PSU to the floppy and the floppy connector to the SMD....

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Post by KanedaFr » Fri May 13, 2011 8:42 am

I think I finished the schematic of the fdd adapter and... I don't understand!

EDIT : link to wrong pictures removed

Yes, the VIn of the 7805 is connected to nothing (! I check 10 or 12 times!)
Yes the outputs of the relay are connected to nothing, a dead end (missing cap) or a cap to ground

So basically, from what I understood, it uses the 5V coming from LPT's Pin8/Data6 (I checked SMD board : it is connected to 5V)....
so I think I missing something...because else,
what the need for the relay ?
what the need for the DC ?
what the need for the 7805 ?
:shock:

a way to get 1A ?
Last edited by KanedaFr on Wed May 18, 2011 9:21 am, edited 2 times in total.

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Post by KanedaFr » Tue May 17, 2011 8:52 pm

Ok....It seems I missed something important : the 'head' of the 7805 is screwed to the metal part of the driver box, and so in contact with the GND coming from the LPT connector.... so the 7805 (and so the lower pin of the relay) is connected to GND, like it must be !

Now I need to find how the 12V comes to the VIn of the 7805 : on my 'current' board, there is no trace nor direct solder. (the reason why my driver doesn't work anymore?)
So if you have one of these (even not working), could you tell me how the pin at the left of the 7805 is connected to the board (or something else) ?

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Post by Charles MacDonald » Sun Jun 26, 2011 6:16 pm

Now I need to find how the 12V comes to the VIn of the 7805 : on my 'current' board, there is no trace nor direct solder. (the reason why my driver doesn't work anymore?)
So if you have one of these (even not working), could you tell me how the pin at the left of the 7805 is connected to the board (or something else) ?
I traced out the PSU of my SMD FDD drive:

http://cgfm2.emuviews.com/img/smd-fdd-psu.png

The FDD connector has a pin on the DB25 connector from the SMD (marked 8a here, I don't know the correct number) that controls the relay. Normally the +9V DC input is not connected to the 7805, and the pin goes high to switch "on" the 7805 input this way. I don't know if this pin is software controlled -- I don't think it is. Perhaps just turning on the SMD drives this pin high (so in a very, very short time interval, the SMD is powered up first and the FDD is powered next).

So the leftmost pin of the 7805 goes to the relay, the center pin goes to ground, and the rightmost pin goes to the red wire of the FDD power connector.

My board is like yours; there is a missing regulator and capacitor. Going by the FDD specification this would have provided +12V power on the yellow wire. I guess modern drives don't need +12V anymore and just +5V is sufficient?

There are two jumpers, unconnected on mine. JP2 shorts the +5V output back to pin 8a. This means once pin 8a is driven high (again, not sure if software controlled or not) it stays high forever until you turn the power off. If that pin was software controlled it would mean you can only turn the FDD on and never off.

JP1 shorts the +12V output back to pin 9a. I'd have to look at the SMD to really figure out the point of doing this. In retrospect I should have traced out the FDD connector when making the SMD schematics. ;D

(Reading earlier posts) Also the 7805 center pin is really connected to the ground pin of the DC jack. You can bypass the relay by removing it and soldering a wire link from the DC jack directly to the positive pin of C1, which will in turn power the 7805 directly so it can't be switched off by pin 8a. I'm not saying that's a good idea necessarily. :)

Let me know if this solves your problem!

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Post by KanedaFr » Sun Jun 26, 2011 8:25 pm

Thanks
Last time, I (re) traced the PSU I found almost the same thing.
I also noticed the pin 8 which drive the relay (I traced it back to SMD)
I also asked me why they used a relay and not used 5V input from the pin 8...but the 1A is the reason I assume ;)

One thing, for me, the default state of the relay is NC : the 2 defaults pins are connected to nothing on my PCB

I haven't other FFE backup device but I assume this PSU is used in some others devices, which still use the 12V (yellow)....


I was pretty sure VIn of the 7805 had to come from the relay output...
But, looking at my PCB, I just saw nothing.
I'm pretty sure it's just a cheap soldering of something but like you can see on these pics, there is NO connection between VIn and something else.

http://img842.imageshack.us/img842/3073/p1060442r.jpg
http://img813.imageshack.us/img813/2517/p1060445.jpg
http://img577.imageshack.us/img577/7015/p1060446b.jpg


I was looking for someone who can confirme me the right VIn source.
Thanks to you, I'm now waiting for a new 7805 and some wires to fix it ;)

thanks again Charles! ;)
ps: if you don't mind, could you check this thread, I think there are 2 errors on your schem but I'm not the best people to fully confirm this)

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Post by Charles MacDonald » Sun Jun 26, 2011 11:27 pm

I'm pretty sure it's just a cheap soldering of something but like you can see on these pics, there is NO connection between VIn and something else.
Wow, it really looks like somebody tried to 'repair' the 7805 and did a terrible job. From the way the solder is stuck to the pins, they didn't use a hot enough soldering iron. On mine the 7805 is soldered correctly, without such a mess. :)

ps: if you don't mind, could you check this
Yes there are some mistakes, sorry. I haven't had the time to fix them. If anyone wants to update the schematics though, here is the original CE3 file for Bsch:

http://cgfm2.emuviews.com/sch/smd-main-v4.ce3

I would just ask that any fixes/improvements are posted here so I can see them ;D

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Post by KanedaFr » Mon Jun 27, 2011 7:41 am

Charles MacDonald wrote:Wow, it really looks like somebody tried to 'repair' the 7805 and did a terrible job. From the way the solder is stuck to the pins, they didn't use a hot enough soldering iron. On mine the 7805 is soldered correctly, without such a mess. :)

Yeah, I have to remove old the solder first...
then find a way to fix the 3 holes else the 7805 will be loose

you could also see the trace of the VIn was totally removed.
It's why I didn't know first if I had to solder it to the trace on the front or or the back of the PCB.
ps: if you don't mind, could you check this
Yes there are some mistakes, sorry. I haven't had the time to fix them. If anyone wants to update the schematics though, here is the original CE3 file for Bsch:

http://cgfm2.emuviews.com/sch/smd-main-v4.ce3

I would just ask that any fixes/improvements are posted here so I can see them ;D
thanks!
ce3 is for BSch3V, right ? I need to download it.
of course any improvement will be posted here (and on the SMDpage)

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Post by Charles MacDonald » Mon Jun 27, 2011 5:14 pm

you could also see the trace of the VIn was totally removed.
It's why I didn't know first if I had to solder it to the trace on the front or or the back of the PCB.
I see what you mean -- there's a narrow trace on the back that goes past the 7805 pins, and a very, very short trace branches off of it to Vin. If the previous owner used too much heat when trying to desolder/remove the old 7805, it would have probably made this short trace peel off. Then Vin would look like nothing connected to it.

Maybe that's why there's no connection on your board, and why there was such a large solder blob to try and bridge the Vin pin to the narrow trace that runs by the 7805. At least you can definitely fix it with wires.
ce3 is for BSch3V, right ? I need to download it.
Yep!

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Post by KanedaFr » Mon Jun 27, 2011 8:42 pm

Charles MacDonald wrote:
you could also see the trace of the VIn was totally removed.
It's why I didn't know first if I had to solder it to the trace on the front or or the back of the PCB.
I see what you mean -- there's a narrow trace on the back that goes past the 7805 pins, and a very, very short trace branches off of it to Vin. If the previous owner used too much heat when trying to desolder/remove the old 7805, it would have probably made this short trace peel off. Then Vin would look like nothing connected to it.
it's exactly what I'm looking for ;)
It's why I'm asking for pics ;) I'm pretty sure this trace is VERY small...
I'm now pretty sure it's on the back of the pcb but, since I missed the head-is-ground point (noob inside!), I was unable to trace the PCB correctly and logically found where was the missing trace.
Can't wait to fix this! It's just annoying me for so long!

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Post by Charles MacDonald » Tue Jun 28, 2011 9:12 pm

it's exactly what I'm looking for ;)
It's why I'm asking for pics ;) I'm pretty sure this trace is VERY small...
I'm now pretty sure it's on the back of the pcb but, since I missed the head-is-ground point (noob inside!), I was unable to trace the PCB correctly and logically found where was the missing trace.
Can't wait to fix this! It's just annoying me for so long!
Ah, I understand now. Should I take a picture of my board, to show you how small this trace is? :D

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Post by KanedaFr » Tue Jun 28, 2011 10:41 pm

Well, it would be great...
I'll so add a clean picture of the PSU on the SMD page...
thanks!

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Post by KanedaFr » Wed Jul 06, 2011 1:24 pm

I'm curious about the jumpers (JP1 & JP2)....
what was their primary goal ? to allow direct input by the DB25, ie w/o 12V input nor relay ?
it's not important for this one but since I learn from anything I analyse, I'm stuck on this one ;)

anyway, I received my tools yesterday...I can't wait to plug my solder iron!

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Post by Charles MacDonald » Mon Jul 11, 2011 12:04 am

I couldn't get a good picture of the trace that goes to the 7805. Here's a terrible blurry one, but I've outlined the trace in yellow so you can see where it is supposed to go. It's probably not helpful, sorry.

http://imageshack.us/photo/my-images/189/smdpow.png/
KanedaFr wrote:I'm curious about the jumpers (JP1 & JP2)....
what was their primary goal ? to allow direct input by the DB25, ie w/o 12V input nor relay ?
it's not important for this one but since I learn from anything I analyse, I'm stuck on this one ;)
If the copier you plugged the Magic Drive into could supply +5V and +12V, shorting these jumpers would allow the drive to be powered over the DB25 connector and you wouldn't have to use the DC power jack.

However the Super Magic Drive doesn't do this. Maybe the original Super Magicom did? I don't recall seeing an AC adapter for that drive. Maybe nothing uses this feature and it was added for future expansion, but remains unused.

The Magic Griffon has an external FDD connector that supplies +5V on pin 8 and pin 9 isn't used. But maybe the +5V is just for turning on the relay which supplies the larger current the drive needs, and isn't for powering the entire drive exclusively, like the SMD:

http://www.tototek.com/phpBB2/viewtopic ... a62c3a0062

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Post by KanedaFr » Mon Jul 11, 2011 8:51 am

Charles MacDonald wrote:I couldn't get a good picture of the trace that goes to the 7805. Here's a terrible blurry one, but I've outlined the trace in yellow so you can see where it is supposed to go. It's probably not helpful, sorry.

http://imageshack.us/photo/my-images/189/smdpow.png/
thanks! it's helpful since it confirms the missing trace
I'll wait for a better one to include on the SMD page but for my own problem, it's perfect ;)

thanks!
KanedaFr wrote:I'm curious about the jumpers (JP1 & JP2)....
what was their primary goal ? to allow direct input by the DB25, ie w/o 12V input nor relay ?
it's not important for this one but since I learn from anything I analyse, I'm stuck on this one ;)
If the copier you plugged the Magic Drive into could supply +5V and +12V, shorting these jumpers would allow the drive to be powered over the DB25 connector and you wouldn't have to use the DC power jack.

However the Super Magic Drive doesn't do this.
Yes, it's what I thought but
1/ Floppy drives need 5V 1A. i doubt a system will use 1A current on cart port !
2/ Floppy drives no longer need the 12V, no ?

so I assume it's a very old design, modded to work on FFE/CCL products ;)

Maybe the original Super Magicom did? I don't recall seeing an AC adapter for that drive. Maybe nothing uses this feature and it was added for future expansion, but remains unused.

The Magic Griffon has an external FDD connector that supplies +5V on pin 8 and pin 9 isn't used. But maybe the +5V is just for turning on the relay which supplies the larger current the drive needs, and isn't for powering the entire drive exclusively, like the SMD:

http://www.tototek.com/phpBB2/viewtopic ... a62c3a0062
ho...interesting, I missed this one...
it must work the same way since it's the same IC floppy controller...
Also interesting to note pin9 isn't used... SMD is older than the MagicGriffon ?

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