Damp - A Cautionary Tale ......

[beteljuice]

Just to show how damp / temp can affect your thermo / hygro unit ......

This applies to LaCrosss 23xx / Technoline, and quite probably Watson (sic)

The beteljuice has been concerned about the external temperatures the last couple of weeks. they seem to reporting several degrees low

So today I took my sensor out of both my hombrew FARS and it's 'normal' box.

There had obviously been some damp (not wet, just damp). Once in the (distant) past when the unit got 'sodden', it became obvious by the RH reported and it's reluctance to drop into line - there is nothing like that on this occasion.

Closer inspection showed some tiny black spores accross the thermistor solder pads

I'm currently drying out the unit, and then shall gently clean the area and apply WD40 (sic) with a cotton bud (don't want to change any resitance / capacitance values by the hygro sensor)

The PCB tracks are fine and close together, and although the board is concoated, that is not true for the solder pads, which are left open and tinned.

I am assuming that the wet late Summer has created this problem, and I am cautiosly hopeful of correcting it - but I can see no way of stopping this happening again, unless I coat the board again myself - but then there is the likelyhood of upsetting the hygo sensor unless I leave that bare.

PS. A replacement unit costs £40, ridiculous

[6719jason]

Hello Beteljuice,

I have been wondering if maybe Damp was affecting my unit, along the similar lines to your reported issues.

I think it is good for all owners of La-Crosse and Watson alike Stations, to be aware of this issue, Thank you Beteljuice

I took the transmitter apart this morning and discovered that it was slightly damp, thankfully no corrosion or black spores.
I think that it is only brought on when it rains, as it rained this morning and as you pointed out to me the other week, it is was likely that the internal instruments were being affected by the damp. Causing frankly stupid Humidity and Dew Point Temperatures. The normal temperature was however unaffected.

I therefore took the decision to overhaul the protective methods for the Transmitter. I lowered the Transmitters height, to around just under 1.5m from ground level (See Pics) This should result in more realistic temperatures without the use of Calibration in Cumulus. I also wrapped a lot of A1 Tin Foil around the Sensor Housing to reflect any morning Sun and excess heat from the transmitter.
While the transmitter was open, I carefully dried the damp off and any rain, then packed the transmitter with a protective fabric like material, and redid the sealant round the edges of the transmitter. I am hoping this may do the trick.

I have attached pics of todays changes, sensor housing and location shots. Any suggestions welcome.

Jason

[bnwrx]

Covering the sensor with foil. Foil does not "breath", so won't that lock in moisture?

[6719jason]

Covering the sensor with foil. Foil does not "breath", so won't that lock in moisture?

Very true. I am at a loss as to what I can do for this transmitter.

[6719jason]

I should probably mention, The Foil only covers the sides and top of the housing and is not used within the housing.

[beteljuice]

Update: Although initial clean up and detox seemed to work, the thermo has not properly recovered from overnight low (currently 3.6C low), and is now being roughly compensated for in software.

Looks like I may have to get a replacement thermo-hygro unit (the unit is 4 yrs old)

Sod's Law - I recently got a 'spares or repair' technoline unit (sic), and the only thing wrong with it is ........ the thermohygro unit

[TwoDogs]

Hello,
I was reading the posts about dampness and thought I would pass this on. My suggestion is to coat the circuits with dialectric grease. It is a non-conductive grease used exactly for the purpose you have in mind. I live on the Wet Coast of Canada and know what moisture can do. The price over the years has gone up for this product but it's still worth it. Since you guys are not it Canada I can't recommend a place to obtain it but try auto supply stores or electronic parts stores. Goggle "dialectric grease" for the exact description and places in your area that might handle it.
Hope this helps.
Take care,
Hal

[gemini06720]

I live on the Wet Coast of Canada and know what moisture can do.

Hal, what are you writing about ... moisture on the west coast of Canada ... I would not call what we have had over the past weeks moisture...

The price over the years has gone up for this product but it's still worth it. Since you guys are not it Canada I can't recommend a place to obtain it but try auto supply stores or electronic parts stores.

OK, I DO live in Canada, more precisely in flooded Duncan (luckily, I live on Mount Tzouhalem at about 150 meters ASL), on (a very soaked) Vancouver Island, just off the main land of British Columbia.

So, where can I buy that 'dialectric grease' on my Island? Or do I have to order the 'dialectric grease' from somewhere on the main land?

[TwoDogs]

Hi Ray,
Luckily I live on top of the hill in White Rock so don't have to worry about the flooding but over on the Island sure looks bad. No flood insurance so the news reports. That damage is going to be in the millions!
I bought my "dialectric grease" at Lordco. Only came in a large tube and the clerk felt bad for me because of the price and sold it to me for approx. 50 bucks. If you were over here I would give you some as I now have enough to do me for the rest of my life. You should phone around to electronic supply places, check out Lordco, Google, etc. You will probably find most people don't know what you are talking about but that's the stuff you need. Do you know a Ham in your area? They might know of a place to get it.
Hope this helps,
Hal

[akasonny]

Beteljuice,

Why does the Beteljuice refer to the Beteljuice in the third-person? Just wondering.
The Akasonny

[beteljuice]

The beteljuice did indeed re-detox the unit and used Lady beteljuices hairdryer (carefully) to dry out the unit - to no avail

Having now paid silly money for a replacement ThermoHygro unit temperature seems to be behaving itself.

I can only assume that either the unit was past its "Sell By Date" or the excessive damp created corrosion / resistance problems somewhere on the board.

P.S. Old Timers Disease ....

Having got the replacement unit I found the middle connector (display) was blanked off - I immediately rang up and complained (I work cabled), then as I was re-packing it, I double checked - It was a close fitting rubber bung to protect ingress to the unit for those who work wireless.