lampshuk
Well-Known Member
When I took Drifter's mast down this winter I took the opportunity to send the M/head wind indicator unit back to NASA for refurb: replacing the direction indicator and fitting a new anemometer cup-set. I was pleased to be able to take this route, rather than replacing the whole m/head unit. Cost < £40, I think, rather than >£100 for a new one. I believe it's about 15 years old.
However, I was disappointed to discover when I got the mast back up again, to find that not only did the w/speed indicator not work, but the direction (which had worked before) was also not working.
To cut a long story short: I called NASA and they gave me enough info about the connections to troubleshoot the problem, which turned out to be the 5-Pin DIN connector connected to the rat-tail off the display. The female connector on the long up-mast cable was a DIY job and though it looked fine from the outside the soldering was poor (dry joints, no heat-shrink or connector lube protection) and 2 joints had failed. I re-soldered it and now have a fully-functioning windicator.
Here's the info: not exactly rocket science (by NASA standards) but I was able to view the wind speed pulses at the mast base connection with my little pocket 'scope so knew the problem lay elsewhere.
Silver = negative supply - all below are reference to this
Red = +5V from display unit
White wire is wind speed data - 1 x 5V 10 millisecond pulse per rev of wind cup
Black = 1 to 4V (approx) depending on angle of wind vane (SIN)
Blue = 1 to 4V (approx) depending on angle of wind vane (COS)
(these two above are 90 degrees out of phase)
--
NASA MARINE
Boulton Road
Stevenage
Herts
SG1 4QG
www.nasamarine.com
However, I was disappointed to discover when I got the mast back up again, to find that not only did the w/speed indicator not work, but the direction (which had worked before) was also not working.
To cut a long story short: I called NASA and they gave me enough info about the connections to troubleshoot the problem, which turned out to be the 5-Pin DIN connector connected to the rat-tail off the display. The female connector on the long up-mast cable was a DIY job and though it looked fine from the outside the soldering was poor (dry joints, no heat-shrink or connector lube protection) and 2 joints had failed. I re-soldered it and now have a fully-functioning windicator.
Here's the info: not exactly rocket science (by NASA standards) but I was able to view the wind speed pulses at the mast base connection with my little pocket 'scope so knew the problem lay elsewhere.
Silver = negative supply - all below are reference to this
Red = +5V from display unit
White wire is wind speed data - 1 x 5V 10 millisecond pulse per rev of wind cup
Black = 1 to 4V (approx) depending on angle of wind vane (SIN)
Blue = 1 to 4V (approx) depending on angle of wind vane (COS)
(these two above are 90 degrees out of phase)
--
NASA MARINE
Boulton Road
Stevenage
Herts
SG1 4QG
www.nasamarine.com