Nintendo 64, CD64 IDE cdrom drive?

[AmmoJammo]

Alrighty, So I picked one of these up for a good price the other day, it worked for 5 minutes, then shut off 



Basically, this device sits under the Nintendo 64, and allows you to load games from CD, pirated games... 

Pulled it apart, realised it had 1 screw in the board out of 4, so I put some new screws in...

Then it still did nothing...
Checked voltage rails, and found no 5volt...

They used a 7805 regulator, dropping 12volt, at about 800ma... they cook themselves...

Anyway! I fitted a switchmode 5volt, 2amp module, 4.98volts, assembled it... no 5volts...
Oops... one of the screws shorts the 5volt rail to ground 

Anyway! much more stuffing around, and it worked, memory socket is epically bad!

I started pulling some of the mods off the board and soon realised what was going on...

They have a 12volt external PSU, regulated down to 5volts for the cdrom drive (and memory back up) that's always on, even when the N64 is switched off...
Then the 12volt rail for the cdrom drive comes from the N64 itself?! yes! the N64's 800ma 12volt rail is expected to power a cdrom drive, and the N64!

But to provide some form of protection, they added a 5ohm resistor in series with the 12volt rail to the CDrom drive, with a 2200uF capacitor across the rail, at the drive side of the resistor, to compensate for excessive load on the line 

But of course, the cdrom drive having a constant 5volt to it, most likely confused it, so they connected a voltage divider to the 12volt rail from the N64, to the reset line on the ide interface, so when the N64 was powered up, the cdrom reset....

HOWEVER! and this is where my question is....
I removed the voltage divider, and disconnected the reset line.... now, the cdrom drive seems to work, but occasionally seems slow to power up... should I reconnect the reset line? what does the reset line do? I assume it has to go high to reset, but this device was leaving it high... is this right?

And, just because I can, onto some pics!







The Voltage divider on the reset line also had a capacitor in parallel with the output voltage...


Three pads/tracks were missing from this IC, it had been repaired, then covered in hot glue... it wasn't very repaired once I pulled the hot glue off :p


I also swapped the cdrom drive out, painted it black, and fitted a red LED to match the N64..


Of course, the reason for removing the capacitor, and resistor from the 12volt rail, and the voltage divider, was to fit a relay, and use the external 12volt PSU to run the cdrom drive, and have it switch off when the console was off!

[ivan747]

Why don't you try supplying the +12V yourself? Use the N64's 12V line to turn on your own 12V and 5V lines. I believe you shouldn't need the 5V all the time, even while the N64 is turned off, right? You could get +12V with decent amperage from an old laptop power supply. If you can't find anything suitable, use whatever laptop PSU you have and use some DC-DC converter off eBay.

That thing looks bulky, you should have space for those mods
And remember to cover all your wiring. You can use heatshrink to cover wires, components and even entire circuit boards, like so:

[AmmoJammo]

I removed the voltage divider, and disconnected the reset line.... now, the cdrom drive seems to work, but occasionally seems slow to power up... should I reconnect the reset line? what does the reset line do? I assume it has to go high to reset, but this device was leaving it high... is this right?

A bit more reading suggests that if the drive is spinning up on power up, it doesn't need the reset line connected to anything.

Its possible that the seemingly slow spin up before was as a result of it getting the +12volt rail from the N64, through the resistor, so the voltage was dropping....
Now that that's been sorted, I think its better...

[marshallh]

You need to power the 12v externally... it's a design flaw of the CD64. Many people through the years modded it in such a way.

[AmmoJammo]

Of course, the reason for removing the capacitor, and resistor from the 12volt rail, and the voltage divider, was to fit a relay, and use the external 12volt PSU to run the cdrom drive, and have it switch off when the console was off!