RAMBO 1.2 vs 1.3

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RAMBO 1.2 vs 1.3

Post by jlmccuan » Wed Apr 08, 2015 12:33 pm

What is the difference between v1.2 and v1.3 ? Will the SeeMe firmware work on both ?

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Re: RAMBO 1.2 vs 1.3

Post by Nylocke » Wed Apr 08, 2015 12:49 pm



Or, the changelog

Add TVS diode to motor outputs (prevents failure due to hot-plugging motor and excessive BEMF)
Add filter capacitors to motor outputs
Add ferrite bead to motor and logic/extruder power inputs
The varistor providing ESD to USB pathway is replaced with a TVS diode
Flyback diode on mosfets now 3A to reduce unique part count
Icoupler decoupling now 100nF at each power pin
Remove solder mask between QFN pins
Shrink 12.5mm capacitor drill size
New footprints for 0603 components
Silk screen fixes
The varistor change from 1.2fp is now in the design and the solder mask is stopped for the component. (electrically the same as 1.2fp)
Patch to 1.2f. Add varistor between USB GND and GND to shunt ESD to USB shield. Done by manually removing solder mask
Assembly yield improvements:
update 0402, 0603, SOT669, SOIC8, and QFN32 footprint
shrink motor connector drill size
remove stop from thermal vias
add overprint to paste layer for fuse holder
fix MX2 and MX3 silk screen reversed
schematic cleanup (no changes to nets)
shrink vias around motor drivers to improve yield in wave process
remove solder mask between Atmega2560 leads
minor rerouts
isolate USB
thermistor over voltage protection up to 24V.
add LC filter to analog power input
board power inputs now support up to 35V
VCC now from built in SMPS, pads are provided to disable SMPS for powering from alernate VCC source
rotate some auxiliary connectors and improve pad size for wave process
change mounting hole type to ease wave process (no more polyimide taping)
Seperate decoupling for each VDD pin on motor drivers
add freewheeling diodes to mosfets
new layer stackup
rework pcb edge noise rail
numerous routing and silk screen updates
through hole capacitors in case they ever need replaced

In short, both will work fine, just "small" changes that don't affect firmware.

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Joined: Mon Feb 09, 2015 11:10 am

Re: RAMBO 1.2 vs 1.3

Post by jlmccuan » Thu Apr 09, 2015 11:49 am

Thanks, Mike. I had guessed it would be OK from the changelog, but wanted to be sure.

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