These units are brand new builds but had some of the LEDs populated backwards. they were corrected, but since "rework" had been done to them, circuitco can't sell them as new, only as "refurbished".
On Tuesday, June 10, 2014 2:37:42 PM UTC-5, Bas Laarhoven wrote: > > On 10-6-2014 20:49, Charles Steinkuehler wrote: > > On 6/10/2014 1:36 PM, Bas Laarhoven wrote: > >> And I don't know whether Circuitco has solved the problems with the > FETs > >> overheating and fixed the other assembly errors on these 'refurbished' > >> boards. > > Good point! > > > > IIRC there were some boards with LEDs in backwards (or was that all of > > them?). Any other issues? The board I got from them (at full price) to > > test with seemed to work OK, but I haven't put in a lot of time printing > > with it. I'm now up to (I think) 4 BeBoPr's (one from CircuitCo, two > > and a ++ direct from Bas via group buys), a Replicape, several CRAMPS > > prototypes, and then a bunch more CNC oriented boards. No one board > > seems to stay connected for very long! :) > > > > I also mostly run 24V (I manually modified a couple of the older Rev3 > > BeBoPr boards, the ++ does 24V natively), which would help to keep the > > FETs cool even if there was an issue with the board FETs, and one of my > > printers uses an AC line power SSR for the bed heater (so virtually zero > > current and no FET heating on what is typically the highest current > output). > > > > On the boards I've seen, J5 is also missing and the EEPROM is not > programmed, so IOmux configuration must be done manually. IIRC > MachineKit will do this properly at start up. > > I've solved a potential FET issue (thermal runaway) on the BeBoPr+ by > adding a heat sink to the HPB FET and using a fuse with lower rating. On > the BeBoPr++ the entire circuit has been redesigned: the FETs have been > replaced by lower RDSon types and proper gate drivers were added. > > One other thing: The BeBoPrs that I've made and sold all use double > weight (2oz) copper plating for reduced dissipation in the high current > section, and beater heat spreading on the board. I don't know how much > copper Circuitco has used for their R3 boards. This could also be a > reason for the FET problems with their boards. > > Reducing dissipation in the power section was one of the reasons to > change the step down converter. But many people still use 12 Volts / > 120W heated build platforms, 19.5Volt or 24 Volt versions are less > common. Another advantage of using 24 Volts is that you can interface > directly to industrial components that run at 24 Volts DC (e.g. Festo > valves for pneumatic control). > > But let's not start promoting all the advantages of the BeBoPr++ since > this thread is about 'refurbished' BeBoPr boards ;-) . > > -- Bas > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
