Updated march 18, 2016: Card Catcher on Mega Drive model 1

[prince tomato]

hello all,

aside from Famicom games i play a lot of Mega Drive games.
i have a PAL MD model 1, VA-4 board,
50/60hz switch, Jap/Eng switch, RGB scart,
and a flashcart.
now, it plays pretty much everything,
even SMS roms, but if i want to play 3Dgames i can't use the Power Base Converter with the necessary card slot for the adapter to plug in the glasses.

so, since the Power Base Converter is just a pass-through
device, i want to wire a card catcher  to the cart slot directly,
so i can use that for the 3D glasses and MyCard games without the Power Base Converter.

here's where it gets a little complicated:
the card catcher i bought is for a Sega Mark III console,
which has a cartridge slot that is physically different from that of the Master System.
only the Card Catcher slot and contacts are identical.

i could open up my PBC to figure out the pin-out from the card connector to the cart slot,
but i am a bit hesitant, because i don't know how easy the contacts for its card slot are to reach,
and i really don't want to damage it, they are pretty expensive.
Mega Drives i have plenty, so i am not really worried about that, and i've opened and tinkered with loads of them.
if the diagram i am after isn't out there i will have to open up the PCB,  but i'd rather avoid it if possible.

so what i am looking for is a cartslot pinout from Sega Mark III to either Master System or Mega Drive,
so that i can figure out what goes where once i open up the Jap Mark III card catcher.
i can't find anything online about successful attempts at something like this, or any other helpful hints,
so i am hoping some clever clogs here can help me along.
i will post every step of the progress here, so if i get this done there will be a tutorial of sorts for future reference.

[chowder]

Something like this?

http://www.raphnet.net/electronique/markIII_to_smd/index_en.php

[prince tomato]

great!
thanks!
there was a very helpful schematic there indeed,
full pinout for Mark III to Mega Drive pins,
exactly what i needed.  
so this will be a pretty straight forward wiring job,
if all goes well there is no need to disect the card catcher-side pin connectors since i can use the Mark-III side contacts for reference.
so when the Card Catcher arrives i will get started right away
Post Merge: March 03, 2016, 11:07:00 am
i used and combined some of Raphnet's schematics,
and got the following results from looking for continuity between:
A) the 35 Card Catcher connector pins,
B) the 44 Jap Mark III pins,
C) the 64 Mega Drive pins,

cardcatcher pins are numbered from right to left, 1 to 35,
seen from the solderside withe the cardslot facing up.

for the sms and md pins i used their standard numbering.
so i will put all these down here,
formulated as "cardcatcher pin- signal - MS pin - MD pin",
so the first one goes: cardcatcher 1st pin from the right-voltage-master system pin B1-mega drive pins 3 and 6-.
i believe i got everything right, and i will hook it up tonight maybe, but if anyone sees something i overlooked or messed up, please correct me.

1--Vcc--B1--3&6
2--WR--B6-- 56
3--mreq--B10--not connected (actually i connected B9 and B10, as i saw suggested somewhere.)
4--RD--B5--32 (on the pbc it runs to that chip that takes care of the issue with the stack that occurs with some game, i might have to leave that one out)
5--M8B--B4--42
6--A14--B18--23
7--A13--A14--19
8--A8--A9--8
9--A9--A10--10
10--A11--A12--11
11--A15 (actually M-07 from card catcher) --B19--34
12--A10--A11--7
13--CE--B10--12
14--D7--A22--37
15--D6--A21--43
16--D5--A20--49
17--D4--A19--55
18--D3--A18--57
19&21--GND--B21&22--1&35&63
20--not connected
22--D2--A17--51
23--D1--A16--45
24--D0--A15--39
25--A0--A1--33
26--A1--A2--29
27--A2--A3--25
28--A3--A4--21
29--A4--A5--17
30--A5--A6--13
31--A6--A7--9
32--A7--A8--5
33--A12--A13--15
34--CONT--B11--not connected
35--Vcc--B1--3&61

updates will follow, every input or thoughts are welcome.
Post Merge: March 03, 2016, 11:07:54 am

[prince tomato]

updated march 5,
i got the whole thing wired up,
but when i switch it on with a MyCard game nothing happens,
when a MyCard and genesis game are inserted at the same time nothing happens,
when only a genesis game is inserted it works fine.
maybe i just need to connect Vcc, gnd, and the D and A lines,
and disconnect the WR, RD, M8B, and CE lines?
i am not an expert on what these signals really are or what they are needed for, if they are needed at all,
so any hints are more than welcome.

note: i tried the 3D glasses as well,
plugged in Missile Defense 3D cart into PBC,
and used the added Card Catcher slot for the glasses.
one lens "shuts" and the other does nothing,
so they don't flicker in sync with the game like they should.
plug the glasses into the PBC card slot and it works perfectly.
also tried with Everdrive, with glasses plugged into added Card Catcher, one lens is activated, but stays on, doesn't flicker.

i did find one little difference between the PBC,
and the Card Catcher, on the PBC pin 20 is grounded,
and on the Card Catcher is is not connected,
so i connected that to ground.
and i bridged pins B9 and B10 on the Mark III edge connector,
which was suggested somewhere, i forget where.
could it be that the card slot in the PBC is more than a passive pass-through, and needs that logic chip to interact in some way?

update march 18, 2016
SOME PROGRESS:

i changed the loose wire for ribbon cable,
and used the Raphnet Mark III to Genesis converter to reconfigure the pinout, and now at least it plays mycard games.
i put a switch on pin B30, and sure enough, if i close the circuit it plays cards, if i break the circuit it doesn't.
so i expected i could play genesis games when the circuit is broken,
but i was wrong.
my guess is there are are some more pins involved in either cart detection, or sms mode,
so the problem might be in either detecting the genesis cart, or switching from sms mode to genesis mode.
any ideas anyone?