o2 Overclocking resistors

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cris_adder
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o2 Overclocking resistors

Unread postby cris_adder » Fri Apr 13, 2012 9:20 pm

Does anyone have the images to the resistor placements for overclocking the O2 180mhz to 200mhz? The link below seems to have the key images missing:

http://www.mechanics.citg.tudelft.nl/~everdij/papa/overclocking_o2_seite3.html

From this thread (viewtopic.php?f=3&t=7770&p=59096), I think this site was translated by dexter1 a while back...

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ShadeOfBlue
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Re: o2 Overclocking resistors

Unread postby ShadeOfBlue » Sat Apr 14, 2012 7:08 am

Here you go:
o2_overclock.pdf
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cris_adder
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Re: o2 Overclocking resistors

Unread postby cris_adder » Sat Apr 14, 2012 3:20 pm

Thanks heaps..!

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Re: o2 Overclocking resistors

Unread postby cris_adder » Sat Apr 14, 2012 4:37 pm

Does anyone have an O2 350Mhz CPU board...? Could you possibly reply with the multiplier resistor positions for that board? I checked my 300Mhz O2 board and it has the following settings:

R47 R48 R49
R51 R52 R53

100ohm Resistor positions are in bold red.

Was thinking that the same trick may work on this board..?

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Re: o2 Overclocking resistors

Unread postby cris_adder » Sat Apr 14, 2012 5:07 pm

The 300Mhz resistors are in series as follows:

Code: Select all

R47-- R48         R49-,
R51-- R52         R53-'


Resistor positions R47 and R48 are in series.
Resistor positions R51 and R52 are in series.
Resistor positions R49 and R53 are in series.

Using the same principle for the 180Mhz, can only swap resistor positions in series, as with the 180mhz and 200mhz boards.

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Re: o2 Overclocking resistors

Unread postby Alver » Sun Apr 15, 2012 2:29 am

Interesting :) I've been looking around for this as well - I've got a 300MHz r12k O2, and would like to try bumping it to 350. Never found a proper guide for that though. Guess I'll monitor this thread for a while :)
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Re: o2 Overclocking resistors

Unread postby canavan » Sun Apr 15, 2012 7:00 am

Probably not the 350MHz Module you're looking for - this is a R7000.
Attachments
r7000_3.JPG
r7000_2.JPG

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cris_adder
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Re: o2 Overclocking resistors

Unread postby cris_adder » Sun Apr 15, 2012 3:18 pm

Thanks for the pictures... it looks to be the same as my 300mhz. The part no. on the underside for the 300Mhz is 030-1493-004.

The resistor placement is the same as on my board, which is below (this is cut from your pictures):
Attachments
Resistors.jpg
Resistors.jpg (39.69 KiB) Viewed 487 times

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Re: o2 Overclocking resistors

Unread postby mapesdhs » Wed Apr 18, 2012 8:10 am

Alver wrote:Interesting :) I've been looking around for this as well - I've got a 300MHz r12k O2, and would like to try bumping it to 350. Never found a proper guide for that though. Guess I'll monitor this thread for a while :)


I've been trying to establish the required resistor positions for 350MHz for ages, no luck so far.

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Re: o2 Overclocking resistors

Unread postby recondas » Wed Apr 18, 2012 9:24 am

mapesdhs wrote:I've been trying to establish the required resistor positions for 350MHz for ages, no luck so far.

If that over clock is important enough, you might have to consider breaking out the soldering iron and doing some trial and error experimentation. You may be able to use the base, overclock speed and resulting resistor movements of some of the other processors shown in that pdf and extrapolate what's needed to overclock the 300Mhz. to 350Mhz.

or you could avoid the potential for risk and continue to wait for ages......
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Re: o2 Overclocking resistors

Unread postby canavan » Sun Apr 22, 2012 6:30 am

cris_adder wrote:Thanks for the pictures... it looks to be the same as my 300mhz. The part no. on the underside for the 300Mhz is 030-1493-004.
That's surprising, since this is a 350MHz R7k:

Code: Select all

CPU: QED RM7000 Processor Chip Revision: 3.2
FPU: QED RM7000 Floating Point Coprocessor Revision: 2.0
1 350 MHZ IP32 Processor

Image

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Re: o2 Overclocking resistors

Unread postby cris_adder » Mon Apr 23, 2012 2:48 am

Yes, the board looks identical to my RM5200! If the resistor positions are the same, then what would the internal serial eprom multiplier setting of the RM7000 board be to yield 350Mhz, this would be 5.83? (350/60)? The clock crystal (60Mhz) is the same. Thought that the multiplier was whole numbers?

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Re: o2 Overclocking resistors

Unread postby Ryan Fox » Mon Apr 23, 2012 4:25 am

Hmm well I've overclocked G4 eMacs and iMacs with some success, using simple solder links, or a ribbon cable and DIP switches instead of resistors...
Or if you're really crafty get plain old resistors with the same value, and build a simple PCB with DIP switches.
Experimentation possibilities would be 'almost endless'
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Re: o2 Overclocking resistors

Unread postby cris_adder » Mon Apr 23, 2012 3:49 pm

Since the multiplier resistor layout seems to be the same as the R7000 board, have ordered a few 66Mhz crystals and will give that a go first, and see if 330Mhz is fine...


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