Author Topic: MKIII Non-LR  (Read 3336 times)

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Offline VaJim

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MKIII Non-LR
« on: May 22, 2024, 02:40:54 PM »
I've got an old MKII Non-LR that basically is still clicking along.  Lately the temp/RH has been off.  I took the sensor our, did some cleaning.  I also had a backup solar panel (same style) and swapped that out. 

During the day, the temp and RH, for the most part, are good.  Once the sun sets, the temp stays fairly accurate but the RH drops to zero and the dew point at a negative 40.

Not sure if this is caused by the sensor itself or a capacitor on the motherboard, like what I read with some of the Davis units..(?)

According to my Rainwise Net data, the battery low reading at night is around 6.2, then it jumps to 7.1 during the day.

Of course Rainwise (or whatever they call thmselves today) are no longer makes parts for this station.
« Last Edit: May 22, 2024, 02:54:05 PM by VaJim »

Offline DaleReid

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Re: MKIII Non-LR
« Reply #1 on: May 23, 2024, 02:39:05 AM »
Just a long shot, but I have had several of those and the majority of time I get funny readings or there are a lot of missing data display areas, I have swapped out the 6 v. battery with a new one (not too expensive, I got mine at a Fleet Farm store in the fishing area).  I fully charged it before swapping it out.

I wish I knew more about the circuit, but there are apparently many different versions of the boards even though they all interface with the same sensors and solar panel. 

I suspected my solar panel wasn't putting out the charge/voltage and that still may be, but during the spring/summer/fall they run OK.

If you haven't replaced the internal 6 v. battery, it is worth a shot and may help. 

I agree, there are a lot of older stations from Rainwise so it is sad to see that service or tech help on the phone isn't available, or at least easily.  The last I spoke with Brian or whomever it was there, I was basically told that repair and service was not going to be available as they moved on.  I hope he was wrong, but if it wasn't a part listed on their web site (like R/H, temp sensor, or wind, or such) there was a good chance he couldn't do anything with it.

Let me know if this kludge fixes it or helps at least.
Dale
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Offline VaJim

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Re: MKIII Non-LR
« Reply #2 on: May 23, 2024, 06:37:18 AM »
Thanks Dale

Yeah...I've sent 2 emails to the last email address I had for Brad and they both were returned.

My battery, according to the RainwiseNet (via the IP-100) appears to be fine.

I'll keep poking around.  The RH and dew point basically stop working about an hour after sunset while the temp is now working fine 100% of the time.

Offline DaleReid

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Re: MKIII Non-LR
« Reply #3 on: May 23, 2024, 07:14:13 PM »
I know it sounds crazy, but I'd not trust the voltage readouts if  you have a less than fully functioning  unit.
It is a pain  to swap the battery, especially if mounted higher  up and with the self retaining screws not always self retaining!

But before I pulled much hair out over this, try the battery swap.  I was in the same position with what was being telemetried as a good voltage but the problem went away when I did the swap.

Obviously I can be wrong, but I haven't any further advice to track things down without a schematic and that was impossible for me to get back when.
Good luck!  Dale
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Offline VaJim

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Re: MKIII Non-LR
« Reply #4 on: May 24, 2024, 07:14:12 AM »
Thanks Dale

A battery swap out for me is fairly easy as I've always kept my station on a tripod at about 6' off the ground.  I'll look into it today.

Jim

UPDATE:  Got the old battery out and my meter reads it at 6.67.  At this point I'll try a new battery for I'm not sure how old the current one is.  I'm guessing 3-5 years.
« Last Edit: May 24, 2024, 09:12:46 AM by VaJim »

Offline VaJim

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Re: MKIII Non-LR
« Reply #5 on: May 25, 2024, 07:48:02 PM »
Well a new battery made no difference.

The outside temp works fine along with the other sensors. 

The RH and DP only appear to be accurate when the sun is hitting the solar panel.

Thanks anyway.

Offline DaleReid

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Re: MKIII Non-LR
« Reply #6 on: May 26, 2024, 07:40:50 AM »
Well, shucks!
I was hoping to hear that you were back on line with accurate sensors.

Did you say you had swapped out the solar panel with another one?  Of course those are hard to find unless you have a big junk box.

I am fascinated by this behavior and if and when you solve it, please let us know. 
I don't recall the specs of the panel, but since this is so reproducible, if a voltage/current source of the right amount were available, to clip that on the panel's socket and see what happens would be of some interest.  I'd just not want you to fry the whole unit with too high a voltage.

I'm beginning to think the power charging/steering part of the unit is goofy, but why and how and why only the RH/temp, which I assume you've cleaned the connections and reseated the plug on the socket if it were a corrosion/resistance in the connection problem.

Anyway, best of luck and it is very frustrating to have a thing that has been so dependable to give problems with no insight into the circuit.  Dale
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Offline VaJim

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Re: MKIII Non-LR
« Reply #7 on: May 26, 2024, 07:49:26 AM »
Thanks Dale

I plan to go back in and check/clean the Temp/RH sensor connection to the motherboard.  I did replace that cable a few years back when the original developed a cut.

I had a extra station from years ago that I've been cannibalizing.  The only thing that is actually left was the solar panel.  I put a meter on both and I believe I'm now using the one with the best voltage.

Offline CW7491

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Re: MKIII Non-LR
« Reply #8 on: May 26, 2024, 07:23:43 PM »
I wonder if you could replace the actual humidity sensor element if you eventually suspect that might be bad. I replaced my Davis VP2 analog humidity sensor element (also no longer supported) with a Vaisala intercap humidity sensor. Works terrifically. I’m assuming the mkiii uses a similar analog technology. If you eventually pull the sensor element, please post some pictures.

Offline VaJim

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Re: MKIII Non-LR
« Reply #9 on: May 26, 2024, 07:37:38 PM »
I've replaced the temp/rh sensor before and it's possible that it may still be bad.  Can't remember when I replaced it.

I would gladly replace it again, except Rainwise or the parent company, as far as I know, no longer make parts of the MKIII (non-LR).

As Dale pointed out, the temp works fine 24/7.  The rh/dp only become accurate when the sun is out and hitting the solar panel.

The old MKIII non-LR temp/rh sensor is about 1x3" with the standard Rainwise plug on one end.  Fits down inside the tube housing below the anemometer.  I think the newer one Rainwise uses (LR) is more square.  You can see a pic of it on their website.

Thanks
« Last Edit: May 26, 2024, 08:14:40 PM by VaJim »

Offline CW7491

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Re: MKIII Non-LR
« Reply #10 on: May 26, 2024, 08:45:58 PM »
I was thinking more of potentially being able to replace the humidity element itself, not the entire temperature humidity sensor. It’s potentially plug and play if it’s analog. With the new combined digital temp/hum sensor chips Davis and Rainwise use now, this is not possible. May be more than you want to get into and it may be a long shot, but I thought I’d throw it out there if all else fails.

https://www.wxforum.net/index.php?topic=46754.msg471888#msg471888
« Last Edit: May 26, 2024, 08:50:00 PM by CW7491 »

Offline VaJim

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Re: MKIII Non-LR
« Reply #11 on: May 27, 2024, 07:06:17 AM »
I’m not sure that’s the case with these old Rainwise units.  As far as I know, the temperature & RH are contained on one sensor. 

Although I’ve replaced these sensors many times, Rainwise used a telephone type plug connector at the sensor.  The cable used to connect the sensor to the motherboard uses a male type phone jack connector.

Thanks

Offline VaJim

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Re: MKIII Non-LR
« Reply #12 on: May 29, 2024, 12:29:10 PM »
Here's a pic of my the temp/rh sensor currently onboard the Rainwise MKIII non-LR.
« Last Edit: May 29, 2024, 01:15:03 PM by VaJim »

Offline DaleReid

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Re: MKIII Non-LR
« Reply #13 on: May 30, 2024, 03:31:03 PM »
I found one of the units I swapped out a few  years ago and it looks like this one. Dale
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Offline CW7491

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Re: MKIII Non-LR
« Reply #14 on: May 30, 2024, 11:40:55 PM »
Here's a pic of my the temp/rh sensor currently onboard the Rainwise MKIII non-LR.

Thanks for posting. Looks like a Sensirion sensor? It kind of looks like a thermistor next to it, but I assume they use the Sensirion for temp and RH.

The version .80 replacement definitely won’t work?
« Last Edit: May 31, 2024, 12:17:12 AM by CW7491 »

 

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