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Building a rev4 board. Capacitors missing from instructions

Added by darrenp about 12 years ago

Hi,

I'm just making my rev4 board, but just got a quick query about the capacitors on it. On the rev3 instructions there are some extra capacitors mentioned in the list of common components, but then no mention of them in the assembly instructions. So, for rev4, are the capacitors C9, C10, C11, C13 and C14 needed?

My laser is on order and should be here this week. Once I've tested it with the awful windows software (after finding a machine with windows on), I'll be swapping out the board and putting my Laos board in! :)

Cheers,

Darren.


Replies (4)

RE: Building a rev4 board. Capacitors missing from instructions - Added by hugomeiland almost 12 years ago

Hi Darren,

according to this schema, c9,c10,c11 and c12 (all 100uf) are for cleaning the signals on the the pololu's
c13 and c14 (both 22nf) are for the 5v to 3.3v power regulator...

Hugo

laos-board.svg (1.39 MB) laos-board.svg

RE: Building a rev4 board. Capacitors missing from instructions - Added by darrenp almost 12 years ago

Ah, thanks. I'd figured out the 100uF ones for the pololu drivers.

Having a closer look, the 5v to 3.3v regulator isn't mentioned in the docs, and appears to be an SMD device (SP6205). Is this critical, or does the processor board have an onboard voltage regulator? J44 looks like it enables the supply.

RE: Building a rev4 board. Capacitors missing from instructions - Added by jaap almost 12 years ago

The voltage regulator is only needed when you replace the MBED with the LPCExpresso.

RE: Building a rev4 board. Capacitors missing from instructions - Added by darrenp almost 12 years ago

Cheers.

I'm getting there. The board is made (note, check the voltage of C4 so that it doesn't blow up in you face! Oops! Also, get the ribbon cable connector in the right way. Double oops!) and nearly functioning. Endstops work, and X axis is homing nicely when turned on. Y axis is just sitting there and juddering when trying to home. Going to debug that tomorrow and hopefully figure out the laser connections.

Thanks for the help people! Once I'm done I'll get the wiki updated.

Darren.

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