Topic: 5 in 1 sensor suite with the sht21 humidity/temp sensor issue

[tarheelbill]

hi everyone...i been reading this forum for awhile and have learned alot through the years, but maybe hopfully someone here can help me out and inturn help others out with same issue. i noticed the other night my humidity and temp were showing -40 f and 1% humidity so i figured change batteries and do full reset to console. nope still the same, and mind you i do regular maintainence to the sensor suite so its well taken care of. also alittle huistory with acu-rite stations maybe will help....im actually a beta tester for them and have been for about 4 years. everything they have sent me has failed...ive stayed intouch with them to help solve isues and even talked to Rinno on here a few years ago about same issue. but they have used different sensors for temp/humidity through the years as i understand. anyway this particular unit has been my third replacement and im to the point of just saying the heck with acu-rite....i called this week and talked to Kevin and explained everything but all they could do is offer a small discount for new suite. Heck i can go to Walmart right now and buy a complete station for 99.00. Just doesnt make sense. Anyway i guess my point is have any of you had similar issues and I'm an electronics tech so i'd love to find a replacement sensor for this unit, ive actually found a place that sells the sht21 sensor chip. acu-rite wont sell just parts, which in my humble opinion they should for us that wanna fix our own stations. also i am in se nc near the coast but not on the beach...thats why i've been so careful with maintainence and all. So sorry for long post but just trying to give as much detail as i could and hope maybe for some suggestions ....thanks 

[nincehelser]

I'd check the circuit traces on the daughter boards on which the SHT21 is mounted for corrosion and discontinuities. 

Simply jumpering around a bad trace might solve the problem.

Some apply extra protective coatings to this board as a preventive measure.

[tarheelbill]

hi nincehelser....thank you alot for speedy reply, ill definitely check those again but didnt see to much corrosion or rotting of traces. Do you know how durable the sht21 sensor is, do they have a hi failure rate or are they pretty durable? One way or another im gonna figure this dang thing out...lol, again thank you so much for your help 

[nincehelser]

Most complaints I've seen have to do with deterioration of the traces.  The -40 condition often indicates a problem communicating with the chip if all other typical problem causes have been eliminated.

As for the SHT21 itself, I haven't heard of specific complaints about it.  There's always the possibility the small window on the chip has become sealed or contaminated, though.

[tarheelbill]

yes i totally understand....im gonna check this thing out more and see if i can get this thing going....ive found a place that i can order just the sensor....so may even try that if all else fails....ill keep yall informed...im determinded to figure this thing out and i hope acurite monitors this forum too...lol..thanks nincehelser

[DoctorKnow]

tarheelbill,

You must not be all that far from where I am. I had a 5 in 1 that had the failure of the thermo/hygro sensor. On mine if you look at the board that goes just above the bottom vent, that pulls out and you can see it is wired from that board to another board. Where mine failed is the metallic flat lines that follow the sensor chip board to the lines that are soldered together to take the information to the next board up for transmission to the console etc.

The way to fix it is described on this site. http://mresoftware.com/acurite_mod.htm  scroll to the second section.

[tarheelbill]

tarheelbill,

You must not be all that far from where I am. I had a 5 in 1 that had the failure of the thermo/hygro sensor. On mine if you look at the board that goes just above the bottom vent, that pulls out and you can see it is wired from that board to another board. Where mine failed is the metallic flat lines that follow the sensor chip board to the lines that are soldered together to take the information to the next board up for transmission to the console etc.

The way to fix it is described on this site. http://mresoftware.com/acurite_mod.htm  scroll to the second section.

Hey doctor know I'm at monkey junction between wilmington n Carolina beach..... I've checked the circuit traces on board n did notice issues but afraid it took sensor out.... I'm n electronic tech so not an issue repairing this but think sensor is shot.... I'm trying to find a replacement ........ Acu-rite doesn't support replacement of parts unfortunately...... But ty for the guidance n any help is always appreciated

[nincehelser]

I know a few people who have replaced or upgraded them just by replacing the SHT21 chip directly on the board.

Some have opted to use a chip on a break-out-board instead.  I'm not sure why they chose to do this.  Maybe to get around some bad traces on the existing mounting board?  Or it might be they were using something other than a SHT21 that is a compatible replacement.  (e.g. https://learn.sparkfun.com/tutorials/htu21d-humidity-sensor-hookup-guide)

[tarheelbill]

Sorry nincehelser n Dr know that I haven't responded n a few days been tied up with the holidays n other issues  I may try to order one of those small humidity temp sensors and try it. Otherwise I can buy a completesystem at Walmart for 99.00. Or may just buy a Davis station and be done with it. I'll keep yall informed. Again ty both for all your help.