Stc 1000 Temp Controller .... I Think I Fried It?

[pokolbinguy]

WARNING - CONTAINS ELECTRICAL BASED DISCUSSION - PLEASE DO NOT GIVE ADVICE ETC IF YOU DO NOT KNOW WHAT YOU ARE TALKING ABOUT.


Hi All,

I have a query for the Leco's out there and in particular LC if he reads this, no doubt he will.

So the story is I have an "STC-1000" temp controller that I bought off eBay.

See this thread Here (Shows unit and wiring of my unit)

All worked well for the past 9 months or more and then I went to turn it on yesterday...and....nothing. Wouldn't turn on. So I took the fuse out, which is glass (M205 10A 250V) They look like this:



Anyway the glass it self was broken, the 'filament' (?) was not...but I have a feeling that this was caused by the removing of the fuse as it clips in a housing before going into the switch. Using an IEC socket Same as Here). To get it out I had to use a small screw driver to lift it out and when doing this I could here the glass break.

So I put a new fuse in it without its plastic housing to see what happens, the fuse didn't blow...but the unit didn't turn on either So seems its not the fuse.

On opening the housing for inspection I found that one of the wires had come loose somehow. The loose wire was the active from the supply to terminal 1 (Supply to temp controller itself), it had come loose where the two wires meet in the screw terminal. No idea how this came loose as all the screws were nice and tight when it was done up. The unit did go on a car ride etc to a mates place about a month ago, but worked flawlessly following that and has not been moved since. All other wires are all still firmly in place.

The wires are marked on this photo:



Any hoo my query is....is there something wrong with my wiring? Considering it worked flawlessly up till now stumps me and that the fuses aren't blowing it boggles me a little.

My conclusions are:

1. the wires in the screw terminal may be a bad idea...and may have caused the thing to clonk out...but it would have only "lost" active.. not earth , nor neutral so should this not "short out" ....sorry if my terminology is incorrect.

2. The unit itself just died and its time to buy a replacement.


Oh and when I put my nose up to the unit I can smell burnt plastic....ain't a good thing. I put everything back together nice and tight...no luck

Any help from the qualified would be awesome.

Cheers, Pok

 

[np1962]

You have probably already done it but I would double check all wire connections, other than that I have no knowledge of this controllers inside workings so sorry I can't help any further.
Nige

 

[pokolbinguy]

You have probably already done it but I would double check all wire connections, other than that I have no knowledge of this controllers inside workings so sorry I can't help any further.
Nige

Yep checked all of them...the smell is what made me pretty sure its died...

Can get a new one off ebay for $32 delivered but a pain in the bum.

 

[LethalCorpse]

Yup, if you've got that acrid smell it's probably burnt semiconductors - output triacs or something. Yes, if you've only lost the active that shouldn't short anything out, but if it's a loose connection arcing back and forth it can cause things to fail in exciting and unpredictable ways. Can you crack open the unit itself so we can have a look in there? Your wiring looks correct (though shorter runs and a few cable ties, heat shrink and a single, screwed down terminal block wouldn't hurt).

EDIT: the fuse definitely broke as you were pulling it out, unless it got that bump you mentioned on the way to your mate's place. I can't see too many circuit faults which could cause the glass to shatter without blowing the filament.

 

[pokolbinguy]

Well seeing the unit doesn't want to work I see no harm in pulling the thing apart for the greater good. It crossed my mind when I was inspecting it anyway.

Will spend some time pulling it apart and taking some photos of its insides when I have some free time, maybe after exams. In the mean time I need to get a new controller because my kegerator is now warm as its controller is keeping my ferment cool....

Pok

 

[barto1308]

Well seeing the unit doesn't want to work I see no harm in pulling the thing apart for the greater good. It crossed my mind when I was inspecting it anyway.

Will spend some time pulling it apart and taking some photos of its insides when I have some free time, maybe after exams. In the mean time I need to get a new controller because my kegerator is now warm as its controller is keeping my ferment cool....

Pok

Just looking at the picture showing your wiring - everything looks correct - the only thing that may be a possibility is that where you have the active and neutral going into terminals 1 & 2 respectively, they are very close together, bending past each other. This may mean that a stray strand of copper has popped out here, contacting between A & N, resulting in a short circuit. This could blow the controller. I also noticed you have managed to jam 2 Neutrals into terminal 2- I had enough trouble getting one in. This may also have resulted in a bad connection. If I were you, on your next controller, do all your wiring the same, but, instead of putting two neutrals into terminal 2, put them all into the neutral connector you have, with just one wire going to terminal two. Technically, makes no difference, but may be easier to do your wiring, and the resulting easier connection will mean less likelihood of poor joins or wires coming loose

2c from an apprentice sparky

 

[pokolbinguy]

Just looking at the picture showing your wiring - everything looks correct - the only thing that may be a possibility is that where you have the active and neutral going into terminals 1 & 2 respectively, they are very close together, bending past each other. This may mean that a stray strand of copper has popped out here, contacting between A & N, resulting in a short circuit. This could blow the controller.

Interesting idea.

I also noticed you have managed to jam 2 Neutrals into terminal 2- I had enough trouble getting one in.

Hmm I swear when I wired this up I didn't do that, So I went and had a look and seems I changed that after taking the photo and before using the unit. The Neutral coming from the supply (bottle RH corner) actually goes to the screw terminal box then there is one wire going to the control unit. So all the neutral wires meet at one central point with one from Supply and one to the unit, heating out and cooling out.

Thanks for the comments anyway. Appreciate it.

Pok

 

[pokolbinguy]

Here you go guys this is what the inside of these puppies look like.





Cheers, Pok

 

[LethalCorpse]

Nothing obviously blown up. If you've got a multimeter, check for resistance between the AC input pins, and then on the back between the two output pins of the transformer. They'll be the two (or three, if it's centre tapped) pins furthest from the AC input, and the transformer is the big orange thing. If you don't have a multimeter, get a multimeter.

 

[pokolbinguy]

Nothing obviously blown up. If you've got a multimeter, check for resistance between the AC input pins, and then on the back between the two output pins of the transformer. They'll be the two (or three, if it's centre tapped) pins furthest from the AC input, and the transformer is the big orange thing. If you don't have a multimeter, get a multimeter.

Yeh thats what I thought, nothing obvious. Could be something on the internals of the transformer (big orange thing)?

Don't have a multimeter, but might get one and see what I can find. If not don't suppose you want the unit LC to pull apart and play with? I have ordered a replacement.

Might go grab one of these tomorrow

Linky

Or should I buy this one - Link

Pok

 

[tavas]

What do you value your time at? Do you consider your time is worth more than $32/hr? Cos if you can't fix it in an hour I'd be binning it and getting a new one. Could be something simple, could be something complex. Unless you have a yearning desire to find the problem....

In my limited experience with all things cheap and electrical, the culprit is usually something cheap to make, difficult to source and damn near impossible to replace without ripping the whole thing apart. I used to go on information quests to find out why things died but now I realise knowledge is very small, my life is too busy and its just not worth my time.

 

[michael_aussie]

Here you go guys this is what the inside of these puppies look like.


View attachment 42046
black things
Cheers, Pok

TY for taking to the time to dismantle and photograph.
FYI - the black things (as you correctly described them) are the two relays.
These are the things that actually switch your heat and cool circuits. They are the things that make the "click" sound.
Nice to see they actually are rated 10A as stated on the spec sheets.

Just a note on the burnt smell - I noticed from the very first time I powered mine up that they smelt like burnt plastic.

Not a good sign for an electrical item.

I wouldn't be surprised if time tells that you get what you pay for.
They are very cheap, so it wouldn't surprise me if they don't last as long as a quality item should.

If they only have 1/2 the life of a fridgemate, then maybe a fridgemate is better vaule for money.

 

[pokolbinguy]

What do you value your time at? Do you consider your time is worth more than $32/hr?

See..

I have ordered a replacement.
Pok

On that note tho I do have some interest in trying to fix it myself, why...just because...I like the idea of saying "I fixed it". Gives me something other than uni work to think about which is nice. And if one always thought that way then why bother brewing? At $32/hr one can buy good commercially available beer alot 'cheaper' than making it...but then that would be no fun would it...

TY for taking to the time to dismantle and photograph.

No prob, if you want any more photos etc let me know

Nice to see they actually are rated 10A as stated on the spec sheets.

Was my sentiment when I read that.

I wouldn't be surprised if time tells that you get what you pay for.
They are very cheap, so it wouldn't surprise me if they don't last as long as a quality item should.

If they only have 1/2 the life of a fridgemate, then maybe a fridgemate is better vaule for money.

Was my other though. Will be replaced with a Tempmate from CB.

Pok

 

[pokolbinguy]

Well the unit has been replaced with a TempMate from Craftbrewer.



I anyone would like a spare STC-1000 temp prob or wants to have a fiddle with the dead unit I have then either or both is yours for the cost of postage.

Cheers, Pok

 

[justsomeguy]

Hey, Pok,

You're not the only one with a dead STC-1000.

Turned one of mine off on Saturday morning then on again later in the afternoon and nothing happened. Totally dead. The kicker is that its only a couple of months old. When I plug it in the Display reads '8' for a split second then nothing. Hitting the power button does nothing.

Did a bit of a hunt around on the circuit and found that its running at about 15 volts after the rectifier. After that pretty much everything goes into the microcontroller which is a little harder to figure out. :angry:

Oh well, time to try something else.

garyd