Bart´s 4 axis Board Capacitor exploding

[soehler]

Hi All

I was using my laser with bart´s 3 axis pololu board and Mach 3 and it was working perfectly.

Today I installed my new LO DSP and wired it to a Bart´s 4 axix board as recomended don Laser 2.x drawings.

I moved the 3 pololus to the new 4 axix board and attached the board to LO 2012 DSP according to the drawings. (left 4th slot with no pololu and did tot connected U to DSP)

When I turned on the Laser 2.X the Y axis started moving and after a few seconds I got the famous blue smoke and popcorn smell. I rechecked all connetions and they are strictly following the connection schema. Any Ideas of what can be going on / what I am doing wrong ? Bart can you help ?

The pololus seems to be ok, see attached board photo swhoing the blew capacitor. (pololus removed)

I aprecciate any help

Thanks

Sergio

[soehler]

It seems to be something wrong I got 8 220nf capacitor with the kit, but the board schematic does not show then ! What are the right ones ?

[bdring]

My board just like yours has run fine with with several versions of that PCB. I made one change after your revision to change the 5V caps (C12,C12,C13,C14) to 0.1uF 50V ceramic caps. I heard that the Pololus don't like a lot of capacitance on the 5V circuit. I think your blown cap is on the V motor circuit.

Try cutting the cap out and running without it. The cap is not really required.

[soehler]

Hi Bart

You mean use to 0.1uF 50V ceramic caps on C11,C12,C13,C14

And about C15,C16,C17 and C18 I can use 220uf or better to switch to 47uF as on the schematics ?

Thanks for your reply

Sergio

[bdring]

The 220uF is probably the wrong voltage. Use a 47uF.

[soehler]

200uF 10V change to 47nF how many volts ?

[bdring]

It need to be rated for the motor voltage plus about 30%.

[soehler]

Got it !
Thanks
Sergio

[soehler]

Bart

I isntalled the capacitors according to the schema (47uF and .1uF) this time they did not explode but .... steppers don´t move although they get enabled.
Previously when the capacitors exploded they staterd to move performing the DSP reset position, Any clues why he steppers are not moving with the right capacitors ?

Any help is aprecciated.

Thanks

Sergio

[BenJackson]

The original cap may have failed shorted, which may have damaged something else.

Also, without a Vmot cap on the laser controller board (the cap under those pololus is 5V) I had one of the input caps on a pololu fail shorted which prevented the other modules from working.