Megadrive v1 installation and connection testing

[andzlay]

Hi guys,

I'm currently installing a megadrive v1 (yes I know that we have 2016, had this laying around for "some" time ).
After I soldered the drive replacement onto the mainboard, I checked the connections with a multimeter and resoldered some points.
Suddenly I realized that, in some rows for a lot of the pins my multimeter beeps, if I check one or more pins to the sides.

For example: When I check on the top-side on the pin marked in gc-md01.jpg, I get a beep on the underside on (atleast) all those marked pin that on gc-md-02.jpg.

Now I wonder: Is this normal or do I suck badly at soldering? As you can see on gc-md03.jpg, there is some space between the mainboard and the megadrive, so I guess it's possible that a lot of solder went between those two boards and brigded some connections. Before I desolder everything and startover, I just want some confirmation.

[megalomaniac]

if you are not getting continuity between top side and bottom side there there is no connection.
since your board is lifted you will need to either desolder the entire board and try to reposition flat or cut some pins from the drive connector you pulled off and use the pins to push thru to the other side to make contact with the mainboard..

you can save time by making sure the two GND pads on the sides are making good contact so you dont have to connect the 10 individual GNDs on the original connector...


glad to see a pic of this board...its so rare

[andzlay]

Hi megalomaniac! Thanks for your answer. The connection is there from top side to the buttom side. I just fear that I bridged some connections under the uplifted megadrive. Maybe those are all the ground connections. Where can I find the complete pinout to determine which should be ground?

Edit: Well I desoldered the megadrive with hot air and tried to resolder it. It was difficult to align the board, because I couldn't manage to remove the solder from the megadrive holes (hint: my soldering skills suck). I get connection on approximately 2 pins and I dont know how I could ever fix this. Yet I could desolder everything again, but I just can't free the holes to correctly align the megadrive on the mainboard anymore.

[emu_kidid]

I remember doing all my Megadrive v1 installs using stripped kynar wire for each connection through the holes, it was pretty hard otherwise.

I'd recommend removing it again, making note of the GND plane pins and any others which have continuity beforehand, and then verifying it all later (or just check a pinout).