Topic: Davis anemometer failing already?

[Mattk]

The technicality and common usage re RJ11 does get a little blurred but not to confuse the usage a RJ11 is typically referred to as a 4P4C, which is narrower than a RJ12 which can be a 6P4C or a 6P6C, however some also refer to these as RJ11's. Typically Davis use a 6P4C (6 position but only 4 pins for 4 strand flat cable) for anemometer, rain collector etc and a 6P6C (for 6 strand cable) for Temp/Humidity etc. Davis serial data logger uses a RJ11 4P4C with 4 strand flat cable   

[dalecoy]

The technicality and common usage re RJ11 does get a little blurred but not to confuse the usage a RJ11 is typically referred to as a 4P4C, which is narrower than a RJ12 which can be a 6P4C or a 6P6C, however some also refer to these as RJ11's. Typically Davis use a 6P4C (6 position but only 4 pins for 4 strand flat cable) for anemometer, rain collector etc and a 6P6C (for 6 strand cable) for Temp/Humidity etc. Davis serial data logger uses a RJ11 4P4C with 4 strand flat cable

Really?

https://en.wikipedia.org/wiki/Registered_jack

And the 4P4C connector is a "handset connector" - which doesn't actually have an official RJ number.

But of course, I'm being pedantic.

[SLOweather]

And the 4P4C connector is a "handset connector" - which doesn't actually have an official RJ number.

Maybe that's a "UJ", Unregistered Jack.

[Mattk]

This is where the real practical side of RJ type connectors gets highlighted against so called standards applied in applications which have absolutely nothing to do with telephones.

[dalecoy]

This is where the real practical side of RJ type connectors gets highlighted against so called standards applied in applications which have absolutely nothing to do with telephones.

Absolutely!

For clarity, perhaps saying telephone-style connector, and 6P4C (or 4P4C where applicable), would be helpful.

[And never mentioning "RJ"]

[Bashy]

I know them as telephone connectors and RJ11's, but, if you say telephone connector to someone over here who does not have a clue, this is there 1st thought

https://en.wikipedia.org/wiki/British_telephone_socket

[CW2274]

I know them as telephone connectors and RJ11's, but, if you say telephone connector to someone over here who does not have a clue, this is there 1st thought

https://en.wikipedia.org/wiki/British_telephone_socket

That's why you guys drive on the left side of the road.

 

[Bashy]

Makes sense, i mean, driving on the left is right but also, our steering wheel is on the right, it would be harder to
drive if it was on the left now wouldnt it ha ha ha

[waiukuweather]

other countries other than the UK drive on the left too
see
http://www.worldstandards.eu/cars/list-of-left-driving-countries/

and the history of why
http://www.worldstandards.eu/cars/driving-on-the-left/

[Tonythesnowman]

Thanks for you comment Dalecoy.

Replacing the potentiometer on the MK. 2 anemometer.

I have just completed replacing the wind-vane potentiometer on my son's Mk. 2 anemometer.  It now works, so we have a spare - better than throwing it away and much cheaper than a new one or a Davis refurb!

The job is much more difficult than on the Mk 1 (see previous post):  Here's how I did it.

(1)  Remove the support tube from the pole clamp fitting (small Phillips screw with nut).
(2)  Screw a wood screw into plastic tubular cable clamp in the bottom end of the tube and pull it out to free the cable.
(3)  Remove the anemometer cup spindle assembly (remove single Phillips screw and click it off).
(4)  Disengage the support tube from the anemometer head and slide it up the cable out of the way.
(5)  Remove the wind vane from its spindle (Allen key)
This exposes the potted electronics at one end (with the top of the speed sensor pickup coil just visible across the centre) and the nut holding the wind vane potentiometer at the other.
(6)  Remove the nut and washer holding the potentiometer.
(7)  Using a small G clamp or a vice, with the cup end of the housing fully supported against a flat plate or piece of wood, GENTLY press the potentiometer and electronics assembly out (towards the cup end).  The potting compound is quite soft and no great force is needed.
(  To replace the potentiometer, it is then necessary to get at the three soldered terminal pins that attach the round circuit board to it.  This means CAREFULLY picking all the the potting compound out to expose the terminals and the rest of the circuit board components.  There are no 'loose' wires to catch in, so this is not too difficult.  I used a pointed kitchen knife.
(9)  For ease of working, I then unsoldered the 4 wires from the printed circuit board, but this isn't essential.
(10) If you have an de-soldering vacuum tool, then un-solder the three large terminals (2 one side and one the other side of the central wind-speed pickup coil.  If you haven't got one (I hadn't), life is harder!  I cut the top off the faulty Davis potentiometer to expose the other ends of the 3 terminals seated in the ceramic top plate of the pot.  I then drilled them out with a 1.5 mm drill, until the circuit board dropped off.  This left protruding pins that I could solder to for the next operation.
(11)  The 3 pins on the replacement potentiometer were spaced differently to those on the Davis original, so it couldn't simply be soldered into the same pin holes pn the board.  Instead, I soldered short 3/4" lengths of thin flexible insulated red, green and yellow wire between the circuit board pins and the appropriate potentiometer pins, arranged so that they could collapse without shorting when the circuit board was pressed down against the potentiometer.  Fortunately, the replacement pot was slightly thinner than the original, so the overall length of the resulting assembly was about the same, in spite of the wires sandwiched between the board and the pot.  (This is important, to maintain a gap between the rotating cup magnet and the pickup coil).
(12)  Resolder the 4 cable wires onto the circuit board terminals (if previously removed).
(13)  Clean any residual potting compound from the housing bore (leaving some to hold the small drain tube in place) and slide the potentiometer/circuit board assembly into the housing.
(14)  Replace and tighten the washer and nut on the potentiometer stem to hold everything in.
Since the circuit board is no-longer rigidly fixed to the pot., it will, in due course, need to be re-potted to hold it in place, but I haven't yet done this.  I need to first find a suitable 'soft' potting compound.  Everything nevertheless works again and the vane registers correctly at all compass points.

Phew!

[EA1EF]

Does taked any photo for us??

Where buy the replace pot, price, and reference it?

Sorry for ask, we replace it in old vanes mk1 with BOURNS  6639S-1-203 but not know noticed  new ones mk2

[Tonythesnowman]

Sorry EA1EF, no photos.  I meant to take some then forgot.

The potentiometer I used was the one I originally got for the Mk. 1 unit but didn't use.  The Bourns 6639S- 1 - 203 that you mention.  Actually it was Vishay equivalent 357B0203MAB251S22 that looks identical.  I got it from RS components in the UK - next day delivery - for about £13.  Had I realised there was a solder in (PCB) version, I might have got that instead, though I recall the pin positions were still wrong anyway.

One thing I forgot:  The original Davis potentiometer shaft has a flat on it, so the vane only fits in one position.  The hole in the vane is correspondingly D shaped.  The replacement potentiometer has no flat (I suppose you could file one on it before fitting it to the circuit board).  I didn't realise, this so drilled out the vane bore instead to 1/4".  It fits fine and the grub screw stops it slipping.  Has the advantage that you don't have to get the pot in exactly the 'right' orientation - you can just adjust the vane on the shaft until N is N.

I've just ordered a 'soft' PUR potting compound to finish the job.

[EA1EF]

Thanks for info, its strange few information about usually problems with wind vane malfunction. Usually vane 0 to 45 degrees north or NE  are pot 20k or SMD 100 ohms in ISS board near RJ11 wind, and speed the SMD 470 ohms near reed or proper reed switch...

[Andy Thompson]

Speaking of anemometers failing, I bought my 2nd VP2 Plus in July of 2011 and I've been through 2 anemometers since I bought it. I am now on #3 but I bought the station right at the time when the brass tipped wind vanes came out and the station actually came with it. But this was still before the days of the new wind sensor so mine still had the old reed switch inside. That one failed because the reed switch quit switching after a couple years and the readings became sporadic on the console.  Then just this year back in May/June the bearings in that anemometer began seizing up so I made a deal through Davis and they sent me a brand new anemometer for half the price on the condition I sent my old one back in a timely manner. What I thought was odd this time was the last two I had replaced they never offered me this deal and I ended up paying full price!

Now mind you guys, but this station is out on our farm where the wind is rarely calm so its constantly spinning. My other VP2 I have in town and I installed that in June of 2008. I've only been though 1 anemometer on that unit. Is this considered a "normal" life span if I can only get a max of 3 years out of an anemometer out in the country?

[ct]

I have some anemometers that are 3 years old that don't seem to spin as freely any more in low wind.  So I bought some Davis 7345.999 Pro2 Anemometer Wind Speed Cartridges to replace the old ones.  Unlike on my anemometers, these cartrides have a cap over the magnet area and a flat disc in the lower part covering the bearings, presumably to keep dust out.  I spun the shaft with my fingers to test out these new cartidges and noticed one of them sounded much different than the other ones, almost a grinding sound.  A few spins later and the shaft had completely jammed.  I had to remove the cap that covers the magnet to see what was jamming it.  The cap doesn't appear to pop off easily, might be glued in place.  When I managed to remove the cap, the E clip that is supposed to hold the shaft in place was not attached to the shaft. It was most likely not fitted on properly in the first place and became detached causing the shaft to jam.  This same problem may explain the issue the OP was having.

[ct]

On further inspection, there is actually an E clip holding the shaft in place.  The E clip shown in this picture is an extra one stuck onto the magnet during manufacturing.  During high speed rotation of the wind cups, this E clip gets thown about in the capped area and occasionally gets stuck in this position where the cups will stop spinning.

 [ You are not allowed to view attachments ]