Mr. Driller

I’ve run some tests to measure the PSU temperature in several different scenarios, both with original GD-ROM drive and GDEMU installed. The most interesting case was one with GD-ROM drive but no disc, and cover completly removed:

DC temp scan

Without any forced airflow the convection alone is not able to cool the radiators below some 70°C. It doesn’t get any worse than this though, basically the PSU reaches thermal balance at this point and stays that way.

With the cover installed PSU will heat up to about 58°C. Running the console without cover and then reinstalling it after some time will cause the temperature to drop eventually. In other words, the airflow inside the case does make some difference.

I’m a big fan of simple solutions so this is what I did:

DC side holes

I’ve also complety taped off the air inlet at the back of the console, so now most of the airflow will go through these holes and cool PSU down. With GDEMU installed it reached 63°C after an hour. It’s just 5 degrees more than with the original drive so I think I’m done making holes🙂

One other point of interest, PSU voltages:

  • GD-ROM drive (no disc): 3.296V / 5.030V / 13.28V
  • GDEMU: 3.305V / 5.042V / 14.26V

Even without a disc inserted the original drive pulls some current from 12V line. GDEMU doesn’t (and uses much less power in general) so it’s possible the PSU is running in a bit less efficient way now.

Keep in mind this a 230V PSU, the 110V one might behave differently. I’m going to test that as well in a day or two. Still, the capacitors in the PSU are 105°C rated so 70 rather than 58 degrees is not going to suddenly damage them. If this thing was properly designed it should handle even less favourable conditions than that. After all SEGA guys did put the fan on the opposite side so overheating the PSU was not a major concern for them.

8 thoughts on “Mr. Driller

  1. I just wondered if you had considered designing the GDEMU PCB to match the size of the stock GD-ROM driveboard? So the GDEMU could fit inside the GD-ROM drive casing using the original screw holes, and maintain the airflow to the PSU.

    As an added thought, i’m not sure how much extra work this would require, but perhaps the GDEMU could replace the original GD-ROM driveboard entirely? So you could connect up the original laser using the FFC cable and still read original disks, aswell as having a short FFC cable connected to a sub-PCB with the SD card slot/switches for user adjustable placement/fitting? In other words the end result would be similar to the MEGAdrive V4 for the GameCube:-

    …Just a thought I had!

    • Let me make sure I understood you correctly: You want GDEMU to bigger, with separate SD board on a cable, and to still require the original GD drive?

      That MEGAdrive V4 does not connect directly do the laser/servos, I’ve yet to see anyone even attempt that. As far as I can tell it’s 100$ (+shipping?) for just the big flat cable. You still need the WASP PCB, and the SD PCB, and the connecting flat cable, and to solder everything down yourself. Also, it emulates the drive at protocol level, just like GDEMU, except this solution promises “True Audio Streaming Fix”. Not exactly sure what it is but my device works well already.

      So, in other words, if you can find at least 10 people who would pay 250 Euro for this, so that I can offset the dev costs, I can think about it. Otherwise, no thanks.

  2. All I was really hoping for was a solution that still allowed the use of an original GD-ROM drive as well as SD card loading, like the Wii Wiikey Fusion which features a ‘passthrough mode’ allowing you to still use the original Wii disk drive.

    Unfortunately I know the Dreamcast doesnt use FFC cables for the drive connections, makes things difficult (Similar to the GameCube) and since there isnt really enough space to intercept the drive interface (Without removing the original connectors and using fine pitch soldering) In my opinion the next best thing would be to replace the original drive board functionality itself. I realise this would add to the work/cost (Such as adding a BA5986FM etc for the laser/servos, a lid switch etc) but perhaps it could be sold as a ‘GDEMU PRO’ at a higher cost?

    Regarding the MEGAdrive V4 – its not very clear on the website (Perhaps on purpose to avoid Paypal issues) but its actually $100 for a full replacement GameCube disk drive with a MEGAdrive V4 and WASP installed – so that its a ‘plug and play’ solution. I only mentioned the MEGAdrive V4 as an example of how the end product could look/function (“the end result would be similar to the MEGAdrive V4 for the GameCube”)

    Sorry if I have offended you at all, it was honestly not my intention😦

    • You didn’t offend me. What I’m trying to say is _nobody_ has made an optical drive replacement at such a low level, and for a good reason – it’s difficult. All required knowledge is trade secrets for companies that manufacture the drives. Somone would have to redo all the work of many years of R&D, and not even get paid for it. I mean, look at the floppy disk dumper projects… And flopies are way, way easier: much lower bit density, no optical pickup with independent focusing and tracking, no issues with rotation jitter, and finally CAV and not CLV.

      Other than that you already know why it’s impossible to create a no-solder passthrough GD emulator – no space for it. So I opted for the cheaper and already working solution where you remove the drive completly. Yes, the SD socket on a cable would be nice but again, single PCB was cheaper. Now, if GDEMU was manufactured in thousands then it’d be a different story…

  3. Tanks for the info, if you will takeout more units I’ll do those holes in the case for better airflow. Thank you very much, waiting for more gdemu units. Thank you!

  4. Why not make the connector to the board a ribbon cable that fits over the original GDRom connector?

    Since the solder pads are visible & the pressure of the connection should keep then pinned to the pads. (Could also use a bit of glue or tape to hold it in place)

    You would then mount it under the GDRom. (With the metal shielding removed)

    • A special custom-made FFC that somehow fits around the connector? First, it’d be expensive – anything custom and not mass produced is expensive. People always have these great ideas that are not really feasible in the real world. Second, I don’t see how it’d make a good contact unless it’s soldered down. The exposed pads might look to be even to the naked eye but are not. Proper FFC connector uses your typical spring contacts and a very tight fit. And lastly, I think you’re grossly overestimating the amount of space between the GD drive PCB and the metal plate covering mainboard. GDEMU is pretty slim but not SD-card like slim.

      Nice try but that just won’t work.

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