First thing was the sensors. Swapping indoor and outdoor sensors allowed the old intermittent and contaminated ones to work in a controlled environment for narrower ranges of temperature and humidity. Then the barometer: once the other sensors were stable, they stopped interacting with the pressure circuit and it was also stable. The backlight was temporarily replaced with two wedge base 12 volt bulbs in series, and will be replaced by summer with cooler LED lamps. After extensive research, I found that the old "holy grail style" rain gauge had a lifetime warranty and sent it back for replacement. The wind instruments were cleaned and installed.
2/8/03 - UPDATE: Ran out of 8-conductor cable when trying to install wind sensors - will try again next week.
2/12/03 - UPDATE: Last night I connected the wind sensors with a CAT 5 jumper (works fine - originally the wind sensors were connected with 5 floors of 25 pair phone wiring and were working!) and now I'm waiting for wind. The indoor temp sensor went wacky when the temperature hit freezing, sending the barometer down to 26.00 again along with the temperature at -40 and humidity at 180%. Swapped the temp sensors back, and the flaky original outdoor one is stable (for now!) It measured 7.5 volts on the black lead and 1.5 volts on the white lead when in failure mode. We had fog at dawn, and I got to set the swapped outdoor humidity sensor at 100%.
3/1/03 - UPDATE: I got some 3000 mcd 12 volt white diffused LEDs from Digi-Key and installed 6 of them in the top (removable) white panel above the LCD. The picture below showshow it looked with two 12 volt dashboard lamps temporarily installed on the rear panel - they were wired in series and run from the 26 volt supply, and made things very warm. With LEDs installed, it's cool and runs about 60 mA in series-parallel configuration on the 26 volt supply. The original blue color is back as well. 10 or 12 of these would provide better illumination, but the bright "hot spots" aren't too bad with only 6.
3/7/03 - UPDATE: Got the new rain gauge on the 5th. RainWise Inc. shipped a complete unit with a counter module for standalone use! I built the bracket and mounted it on the 6th, so rain data will be showing on the graph pages. It was installed in the rain, of course - and is mounted under the wind instruments in the lower right picture (picture not updated yet.)
3/13/03 - UPDATE: Joined the Citizens Weather Observation Program. Also ordered a new indoor humidity sensor element.
5/10/03 - Moved the outdoor temperature sensor around the corner. Now for the sun to hit it, the sun has to be at 295 degrees azimuth and between 15 and 3 degrees elevation, which only happens in late June and is also blocked by trees.
5/18/03 - Removed the intermittent humidity sensor for service.
5/20/03 - Repaired and reinstalled the indoor humidity sensor. Found the control on the board goes both sides of zero - regular and negative slope. Also found that some people are using a 0-5 volt solar cell array to measure sun intensity on the indoor humidity sensor input, but APRS doesn't report it, so it's not useful here. (See APRS telemetry for how I do that on a KPC-3!) Ironic twist: APRS reports outdoor humidity as the "h" field, and the Heathkit reports outdoor as "H" and indoor as "h". Same goes for temperature.
5/21/03 - Repaired the outdoor humidity sensor. Seems that the 200k pots (204 resistance value code if you're raiding the junkbox for one) are very unreliable. Do NOT replace it with a 100k! If you do, you'll wind up with ONLY negative slope. To check which slope you're on, breathe on the element. If your voltage/humidity increases, you're OK. If it decreases, you need to rotate the pot to decrease the voltage/humidity and pass through a "dip" to the other side where it increases again.
5/23/03 - Installed a "YTD" (year to date) rainfall display. Took a Red Lion Controls CUB3L six digit counter (the RainWise unit only has 3 digits/9.99 in. max) and interfaced it to the rain gauge input with a 10k resistor to a PNP switching transistor. I also cut the "reset" button down on the front of the counter to eliminate accidental resetting.
2005 - Still working, but found the LEDs in the backlight only last a short time, although run at manufacturer's rated voltage. Also have moved the humidity sensor around the corner to where the temp sensor is, and after fighting a drying out problem with the element all summer, it seems to be working. Have set up a maintenance schedule for the rain gauge, which clogs with dirt (not leaves) every 6 months when unmaintained.
6/30/10 - Backlight has been replaced again with a $18 Ebay white LED strip. Also recovered from a March computer crash. Replaced the outdoor temperature sensor with a D8apro board and sensor unit after intermittent 20 degree jumps happened during daytime. At least it was stable for the last 7 years...wonder how many of these are still working after 20+ years.
10/1/2012 - The potentiometers for all settings have developed flat spots, and I barely got everything tweaked back to near-normal. I've scheduled downtime for replacement after the holidays, and will be pulling the old pots, matching the new ones (Digi-Key again), reinstalling, and reconnecting the spaghetti behind the unit with toroids on all leads. This is NOT a project to do with the unit on-line! Also for next year...whacking all the weeds and trees that grew up next to the rain and wind sensors. The humidity sensor will also get a radiation shield and a good cleaning, since it has drifted since being hosed by a pressure washer.
1/12/2015 - I finally got the rebuild done. I removed the old pots (3 were almost unmeasurable!), ballparked the new ones, and reassembled it. Nothing. Checked and found the pins had been misaligned between boards. Fixed that, powered up again. No indoor humidity. Found my miswired quick disconnect problem, powered up again. All settings were screwy. Found the loose wire on indoor humidity's screw terminal. Powered up, tweaked to match the airport weather, and looks good so far. Next up - rebuilding the outdoor humidity sensor...again. 2/28/15 - Found indoor temp and outdoor temp were backwards - reconnected to correct terminals and recalibration is ongoing. New pictures of old stuff will be coming soon.
It is currently running on WXSolution via internet only on a 2.4 GHz P4 via APRSWXNET or Weather Underground.
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