I've been trying to solder to the serial connector on the top of the Dreamcast mobo with limited sucess. I can confirm that once, for a little while, a properly assembled SD card circuit mounted on veroboard did work. Was fully able to read the filesystem using Dreamshell. However I had to disconnect all of the wires from the port as something was causing the DC to refuse to boot up when the shielding was screwed down. Seems it was a VGA wiring problem because as soon as I redid the wiring to/from the video connector it worked just fine. Go to reinstall the SD card board and it won't recognize the SD card. This is what I know so far: 1) The SD card itself is fine, reads just fine in PC based readers. 2) There are 0 shorts. Checked every solder joint myself twice. 3) Everything looks properly wired from the DC connector to the veroboard. The first time I redid the wiring I was trying to tie DC pins 3 and 8 to 3 and 6 on the SD card side without putting in a connection anywhere to ground...smooth. 4) Every solder joint is solid according to my multimeter. Visually they look fine and the multimeter confirms that each pin on the SD side has a connection to a pin on the DC side. My only possibilities run down to: 1) Dead serial port 2) Some moron missed something when checking everything. I don't have any way to test the serial port (no versus cable, no NGP link cable, etc) so I can't rule it out at this point. I suppose its possible I miswired something when I was exhausted the other night and fried something. Does anyone know if there are fuses to check? How about something along the traces that can be fried? The traces from the connector to the immediate vicinity check out fine. Halp! I'm going nuts here. :banghead:
If you can post some pictures with close ups we might be able to spot something you might be overlooking. which diagrams did you use? I'll be doing a SD mod in the near future and would like to avoid any problems.
Pulled them off last night and nothing. Still refuses to see the SD card. Guess I'll have to wire up a new board from scratch to a different Dreamcast. Must've fried something.
As far I know serial port is connected directly to the CPU, static can kill it. If you remove the caps and/or resistor you can ONLY use 3.3Volts devices, 5V ones will kill the serial port in this case.
Perhaps I should bypass the connector on the rear and see about connecting it somewhere else along the path. I wired up a second SD card slot, just need to get some new capacitors. Might have fried the caps by accident I suppose.
Two thoughts: http://www.epforums.org/showthread.php?57461-NEWS-Dreamcast-SD-Adapter 1. Using the diagram there (same as jj1odm's diagram) the 0.1uF capacitor isn't labeled as being polarized. The 0.1uF capacitor I used was a polarized (labeled as polarized) electrolytic. Would this make any difference? I'm leaning towards yes but I don't have any reference material on hand and its been years since I've been in a classroom where capacitors were being handled. 2. After comparing the schematic and what is on my board it has become clear that the 47uF capacitor is reversed in order with the 0.1uF capacitor so that the 0.1uF connects directly to the 3.3v source and the 47uF capacitor is next in line but connected directly to the SD card slot. I'm assuming this isn't a big deal but I also do not know precisely what function these two capacitors are performing beyond working with power. I'm suspecting there might be a reason that they are in the order they are in that schematic. Any thoughts? Gotta find me some good books on electrical engineering I suppose. Being an autodidact has limitations.
If the capacitor has to work both way, it's important that it's not polarized. I believe it's important. Where in hell have you find such a small capacity capacitor in polarized form factor?
You know I haven't a clue. It was in a set of storage bins I have for components. The leads weren't cut or tinned which suggests that it wasn't a salvaged component. Guess I should start by replacing it and swapping the order of the capacitors. Just bizarre it'd work the first time I test it and then die.
