Datamarine wind instrument

[GBM]

I have an old Datamarine Wind Instruments - LX-360, I think. It has worked
fine up until now, but this year, the wind speed just reads 0.00, while
direction works fine.

I plugged the masthead unit directly into the back of the display, and there
is no change, so presumably cable is OK.

I see from http://www.dmimarine.com/ that there is a masthead speed rebuild
kit. Has anyone done this? Are there any checks that I could make to see
whether problem is in head or in masthead unit?

Thanks

 

[Lynn Coffelt]

I have an old Datamarine Wind Instruments - LX-360, I think. It has worked
fine up until now, but this year, the wind speed just reads 0.00, while
direction works fine.

I plugged the masthead unit directly into the back of the display, and there
is no change, so presumably cable is OK.

I see from http://www.dmimarine.com/ that there is a masthead speed rebuild
kit. Has anyone done this? Are there any checks that I could make to see
whether problem is in head or in masthead unit?

Yes, and yes. It's been a while, but in a prior life, did lots of
masthead rebuilds. Testing can be simple if you can find the "pinout"
(connections) on the connectors. (I don't have that data anymore)
The masthead speed unit is a sort of AC generator, and with a scope,
old analog multimeter, or even a pair of headphones you can see or hear the
output of the generator while spinning the rotor by hand.
The indicator can be tested for basic function by driving the speed
input pins with a fairly low frequency square wave from a function
generator.
Big problem was having schematics of the connectors to see just what
pins were to be connected to the poor man's test equipment.
For a long time, Datamarine wind instruments used the same connectors,
and it was usually easy to spot a spinning Datamarine masthead unit on your
same dock. Visit (with best manners, and maybe a couple of cool ones in
hand) and ask to hook up your instrument to his functioning masthead unit.
(power connections too)
Old Chief Lynn

 

[GBM]

Yes, and yes. It's been a while, but in a prior life, did lots of
masthead rebuilds. Testing can be simple if you can find the "pinout"
(connections) on the connectors. (I don't have that data anymore)
The masthead speed unit is a sort of AC generator, and with a scope,
old analog multimeter, or even a pair of headphones you can see or hear the
output of the generator while spinning the rotor by hand.
The indicator can be tested for basic function by driving the speed
input pins with a fairly low frequency square wave from a function
generator.
Big problem was having schematics of the connectors to see just what
pins were to be connected to the poor man's test equipment.
For a long time, Datamarine wind instruments used the same connectors,
and it was usually easy to spot a spinning Datamarine masthead unit on your
same dock. Visit (with best manners, and maybe a couple of cool ones in
hand) and ask to hook up your instrument to his functioning masthead unit.
(power connections too)
Old Chief Lynn

Hi Lynn,
If I switch the head on/off several times quickly, I get a read out on the
windspeed. This 'may' say that the head is OK. The shaft in the masthead
unit is "sloppy" - I contacted DMI and they say that the bearing goes and
takes out the windspeed. They have a rebuild that costs $79.00. Probably
worth a try? I will open it up first and see what gives.

Thanks for the reply!

 

[Lynn Coffelt]

Hi Lynn,
If I switch the head on/off several times quickly, I get a read out on the
windspeed. This 'may' say that the head is OK. The shaft in the masthead
unit is "sloppy" - I contacted DMI and they say that the bearing goes and
takes out the windspeed. They have a rebuild that costs $79.00. Probably
worth a try? I will open it up first and see what gives.

Yes, by all means, take the head apart first. I'm sure, from what you say,
it's shot, but half the problems in using the rebuild kit are in
successfully getting the head apart without ruining something.
Good Luck!
Lynn