STC-1000 jumping temperature

[robotsyte]

Hi all!

I bought an STC-1000 from a local seller, and installed it into my fridge. My problem is, that the temperature is jumping so high, it is around 1-7 tenth of a celsius. I already changed it to another one, from the same seller. But shown exact the same issue.
Do you have any idea, what I should do with it?

 

[MHB]

looks like the power in isnt stable.
Check the lead, the connection on the back of the STC, the power point its pluged into...
Marl

 

[robotsyte]

looks like the power in isnt stable.
Check the lead, the connection on the back of the STC, the power point its pluged into...
Marl

Hi!

Yes it looks for me also power problem. When the jumping is starting the screen also has some blinking (I doesn't seem on the video).
I rewire it many times also with different cables, different wall plug etc.
Can it be a problem we have 228-240VAC?

 

[MHB]

I'm not sure how frequency stable the STC is we use 50 Hz here, in the US its 60 Hz, if your well outside that range it could be a problem. I would expect your local supplier is aware of what is required in your local.

I would try a different power point, if that doesn’t help try changing out the lead from the STC to the power; check all your connections...
After that its talk to a sparky (electrician)
Maybe take a photo and post that.
Mark

 

[robotsyte]

We have 50Hz too in Hungary. I changed the power cable already, and plug it into som other wall point, and many time reconnect the cables, but still has the same issue. I'm wondering, that there is a problem in the power circuit inside the stc-1000, and some time it makes wrong voltage, maybe less or more then it should be.

 

[TwoCrows]

I have had many issues with Stc1000's. I have purchased 5 or more over in the last 4 years . Temperature readings all over the place and not turning on at a set range.
I like the idea of wiring a mechanical rely to handle to load side. The stc1000 is only the switch.
I have moved on to retail ready temp controllers and have found them to be reliable.

 

[livo]

I have 2 and they work ok for me. The second one I bought arrived with a cracked housing so the seller refunded 50%. Still works just fine.

 

[Grok]

Make sure the sensor wire is not close to any mains power wires may help.

 

[TwoCrows]

The last few I purchased regarding the sensor wire.
They have added a micro pico socket and plug. This is not ideal if you wish to add your own. You will need to splice or add a new plug.

 

[robotsyte]

Hi all, thanks for the replies!

I've got a bit closer to the problem during the weekend. I disassemblied the device, and make it work on the table, without any issue. But when I heat it up a little bit with a hairdryer, start the jumping again. The heating was only about 40°C. So it looks, some parts on the PCB not correct.

 

[Grok]

If you have a decent soldering iron, I would retouch (solder) any joints that look suspect, or any at all really just to be sure it isn't a dry joint, and have a magnified close inspection of the PCB for cracks.

 

[DucatiBoyStu]

Hi all, thanks for the replies!

I've got a bit closer to the problem during the weekend. I disassemblied the device, and make it work on the table, without any issue. But when I heat it up a little bit with a hairdryer, start the jumping again. The heating was only about 40°C. So it looks, some parts on the PCB not correct.

Your problem is the probe. Try a different K-Type

 

[robotsyte]

Hi!

I don't think so, when I said to heat it up, I heated up the panel, not the probe.