[time-nuts] Thunderbolt serial port problem UPDATE
Arthur Dent
golgarfrincham at yahoo.com
Thu Apr 14 16:04:47 UTC 2011
What I have done with the displays I got from Fluke.L is lift the end of the
interface board and hold it away from the display board just enough so I
can heat and remove the 5 volt regulator and replace it with a jumper. It
might be a little easier to just lift the input and output leads off their
solder
pads and leave the chip there but I removed the chip as well. I'm supplying
the display with a regulated 5 volts so removing the regulator from the display
assembly eliminates one of the possible problem area by removing one of
the heat sources from the board. Some people have had problems with the
regulator shutting down if they supplied it with 12 volts and the chip went
into thermal shutdown.
Next I remove the 3 zero ohm resistors (that are where the 3 diodes should
have been installed to drop the 5 volts to ~3.3 volts for the CPU) and replace
them with a red LED with leads long enough so it can be on the back side of
the interface board because there wasn't enough room between the boards for
the LED I am using. I have some SMD red LEDs but decided they might be
too hard to solder between the two boards. The red LED makes a pretty good
~1.7 volt zener diode so now I have the display powered by 5 volts and the
CPU powered by ~3.3 volts which makes it happy.
-Arthur
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