"Let's make GD ROM emulation happen" Facebook group.

What are the offsets and allocation sizes of each drive?

 

Shouldn't even a fragmented HDD be far faster than the GD-ROM drive? You'd need some serious fragmentation to slow the read speeds to below the abilities of a 12x CD-ROM drive.

 

That depends on the drive, seek time, etc. So in my case, I formatted a HD, then threw 300+ GB of data on it. The GD-ROM games were made to read data in sequence, just as a HD would once it is defragmented. At this point there should be very little comparison in speed.
Looking at the comparisons between the GD-EMU and USB-GDROM you'll see seek time take effect on the parts where the USB-GDROM is slower. Both devices would be limited in speed by the Dreamcast's bus speed.

 

The HDD in question, doesn't need defraged also it's an issue with just the UGC & this specific HDD.

The HDD & enclosure work on all other devices bar UGC & the same enclosure works with other HDD's & UGC, ie, my Seagate 500GB & the samsung 320GB HDD's work with the enclosure.

I guess UGC just doesn't like some HDD's & USB Pen Drives.

 

i believe that UGC cannot provide enough power it is not an adapter problem nether UGC it is by design try external power

 

I'm not sure this information is of any value but here it is.

In testing the voltage of the DC PSU I get the following;

Without the resistor I get about 13.56v and when loading a game it'll reach 14v.

With the resistor at startup I get 12.64v. In the USB GDROM menu I get 12.28v. When loading a game I'll get a spike up to 12.78v.

Without the VGA box (hanzo) connected, in the menu I get 12.36v. With vga box connected I get 12.28v so not much of a difference. 5v and 3.3v are normal.

 

What resistor to use though? DId you agree on 200mA, 60omh? =) For someone who skipped school to much, what do I order in terms of Ohms and watt?

 

SO where is the HDMI board for Dreamcast... I want one !!!

 

I'm using a 300ohm. In this video you'll see where to insert it. No soldering is required.
https://youtu.be/MVKN3pQ11wM

 

AWESOME VIDEO!!

 

Thanks! So 300ohm, 0.25w =). Clean your joystick ports by the way, hehehe.
Something like this: https://www.microkit.se/search_result.php?qf=2329916

 

Lmao. That's not my video . My consoles are minty fresh .

 

Heheh, so are mine =)

Speaking of which, if anyone in Sweden wants a dreamcast with a broken/semi-broken GDI rom to use for either solutions here, let me know. I recently purchased a lot of broken consoles which I've repaired and cleaned up. Got about 9 working, part from the GDI rom. Way better to slaughter one of them instead of your, possibly, working dreamcast.

Funniest repair was one marked "Picture goes black sometimes". I opened it up and saw that the fan cable had twirled itself into the fan blades so it did not spin as it should. Pushed the cable out of the way = fully working DC =)

 

i made some measurements with the gdrom attached

0.50 A MAX (For half second on start)
0.17 A AVERAGE
0.25 A SEEK
0.06 A MIN (NO DISC)


13.10-13.20 V MAX (No DISC)
12.89 V AVERAGE
12.65 V MIN (For half second on start)

i will try different resistors in 1-2 days with GDEMU

 

Please I dont understand why some of you use a resistor? Must I do this too with my DC VA2.1 NTSC J, VGA cable and USB GD ROM?
Thanks

 

If there nothing connected to the 12V port of the DC PSU, it can increase its voltage up to 14V and generate more heat in the PSU itself. A fix for this is to put a resistor on the 12V line in order to stabilize it. Ideally you'd put the highest resistance value that stabilizes the voltage around 12.5 or 12.3 volts. You can also simply remove the DC PSU and use a more efficient one.

 

Thanks very much.

Does exixt DC official PSU more efficient than other, how to recognize it, and how to know if my PSU need a ressitor?

 

It's not that some PSU aren't efficient enough, it's that they weren't made to have their 12V line usnused, and strange things happen in this case that lead to overheating.

It's better to try to reduce the excess heat made by the PSU, to increase its lifetime and that of the console, but I've yet to see anyone breaking anything because of it. Any picoPSU should work.

See there where Kuririn84 and myself posted pictures of installation: https://www.assemblergames.com/forums/showthread.php?53856-Replacing-the-DC-PSU/page4

 

Hey all, just a quick note to say the Rebuild GDI tool works really well for me. Only tried six games so far, but if it only works for six and saves me 5GB, I'm happy

Thanks for all your efforts… it'd be wonderful to see a Mac port, and if I knew more Python I'd have a go at building a GUI for the tools.

I'll also be dropping a resistor in this week to steady the voltage too.

cheers

 

I also tried the Rebuild GDI with 5-6 games but none of them worked with USB-GDROM. It tried to load them and jumped back to the main DreamCast menu =(