voltage mod of CD-ROM

[calypso_ri]

I came to an idea about how to mod the CD-ROM, so it spins faster... But, I don't know if it'll work...

Now, the basics...

Every CD-ROM has got one voltage regulator (78XX) to drive the motor with constant voltage... Values are often in range 8-10V...
It can't be higher because of 12V rail for mechanics...

So, what I want to do...

Drive the mechanics with 17V (-5V,+12V), and use 7813 or 7815 instead of 7810...

It'll raise the speed of the motor, that's for sure... But... Can I be able to read the CD's? Should I need to precise calibrate the laser with the pot or what?

Any ideas?

This is pretty possible!

OK, guys, I don't know if I'll have the time to do this... If somebody would like to try, drop me an e-mail... [email protected]

 

[Iron Hawk]

I dont think you are going to bet it to read without some serious calibration (getting the laser to read faster). also the motor may only be rated for 12v and may burn out after continous use at 17. You can try it and post your results if you want.

 

[M00CH]

id try it with a older druve first maybe a 6-8x cd-rom do a bench before the mod then after.. and if it dosent work your not not a 50x cd-rom

 

[calypso_ri]

Well, I think I've found a way how to do it without dropping all voltages 5V down! )

Just get a wire (long one!)... Connect one side to the -5V rail on the ATX mobo connector, and the other side to the middle pin of the 78XX voltage regulator.

With this you can lower the GND of the voltage regulator to -5V, which will give you (with +12V input) the total voltage of 17V on the input... So, you can use 7815, and that'll give you 15V on the motor!

Don't know if it'll burn the motor, but I don't think so... Try to measure the current ratings, and post back!

It's a good idea to use 6-8X CD-ROMs for testing! )

 

[CrystalMethod]

I like the idea, but I'm still not sure if it'll still be able to read CD's afterwards.

 

[drunkmonkey]

well, theoretically, if you jack up the voltages, everything should go faster BUT, what about the IDE connection? Will the mobo like the new increased voltages? will voltage regulators screw everything up?
You will have to be extremely lucky to find have equipment that would support this. But its worth a shot.

 

[calypso_ri]

Well, about the mobo... Motherboard doesn't have anything to do with the voltages supplied inside the CD-ROM electronics... The IDE connector has it's own voltages...

What I am doing is just increasing the voltages on certain motors... Spindle, laser-positioning and tray motors...

Till now, I have some improvements... I took ACER 10X drive, and replaced 7808 with 7812... And, what happened? I thought it is for laser-positioning, but #$%@#@$, it's not! ) It's for tray open/close motor!

Now the tray opens in 0.80 sek, and closes in 0.75 sek! )))))))

Seems like I could do some more work on it... But, what really bothers me is LM317T regulator which is variable... From 1.2V to 36V, and I don't know where are resistors that are controlling the output voltage of this regulator! When I find them, I'll surely give them what they need! @#$%@#!

Or I'll measure the voltage it provides, and replace ti with 78XX... I don't like messing up with SMD resistors! )

 

[drunkmonkey]

Well uhh, is it reading cdroms now?

 

[calypso_ri]

Well, AFAIK, the tray can't do anything to reading CDs...

BTW., I tested it once again... Opening is 0.80 sek, and closing is 0.88 sek!

You'd like to see this!

I will get some bad CD-ROMs this week, so I can start tweaking them... At least one could work!