STC 1000 temperature controller

[A C Hunter]

I ordered a temperature controller from Asia and received the 230 volt model instead of 115v needed. I know, buyer beware etc...
Could reorder at about $25, but my pride says 'fix it'

Had it jury rigged with my 5kw 230v heater; I know it works.

Can someone point me to a replacement power supply?
The on-board unit is:
BCY-432 3034
230v 50/60hz input
10v 1.35va output
WUXI XINCHANG ELEC

Best bet would be direct replacement 115v - where can I get one?

Other options: 9v battery? power brick? It will be going in a project box and controlling a keezer so all circuits can be hidden.

Don't have a lot of access to digital electronic test equipment but have a good digital multimeter and a 1960s analog scope.

Any thoughts?
AC

 

[alec_t]

Have you actually tried it with 115V input?

 

[A C Hunter]

Have you actually tried it with 115V input?

No, I have not.
What might be the downside? Any potential damage?

 

[Mr RB]

It's unlikely to damage the power converter, but using 110v input might cause the output to be undervoltage and there is a small (unlikely?) possibility that could damage tot he rest of the controller product.

The safest bet would be to disconnect the power converter, and connect it to a 10v 1W load, then try powering it from 110v. If it can't cope you will see the 10v output is not at the correct 10v.

 

[A C Hunter]

May give the 110 a try this afternoon. Don't care to pull the ps off the board unless I'm planning to replace it. Solder bridges etc.....

Wish me luck

 

[alec_t]

Is it like this one (at least for size)?
**broken link removed**
If so, it's almost certainly got a SMPS in it. Running that at half the spec voltage could double the current drawn and lead to over-heating

 

[A C Hunter]

Apparently this comes in 2 flavours 220 or 110 depending on the country shipped to.

https://www.ebay.ca/itm/All-purpose-Temperature-Controller-STC-1000-Whit-sensor-/320628773067

Will try to post a pic of the inside later.

 

[Mr RB]

... it's almost certainly got a SMPS in it. Running that at half the spec voltage could double the current drawn and lead to over-heating

True, that would be more critical if he was running near the capacity of the unit.

Also many SMPS will tolerate large voltage range on the input pretty well, they just adjust duty cycle to suit, and the average inductor/transformer current will follow the output current.

Many SMPS supplies come specced at 100-240v. And the 240v ones can usually be operated fine at 110v. (However when they sell 110v units you can't use them on 240v as they put lower voltage electros in the primary section to save costs).

 

[A C Hunter]

Not sure whether pictures will be viewable, or be too small to show details.
On the left, the keezer with pint #1 pulled. Currently I can have warm or frozen beer; that's why the controller is important!

I tried 120v and the display and sensor seemed happy, but voltage seemed too low to close relays. Laser thermometer showed no heating.

A bit rusty on electronics, but at 225v, multimeter showed about 14 volts AC. Seems to me that would be 'peak'.
At 120v, got about 6v output, apparently not enough for the relays.

Supply dimensions are about 28x33 mm, 22 mm high. Where do I find a replacement?

Thanks guys for your valuable feedback.
AC

 

[alec_t]

Can you post bigger (not huge!) pics (particularly pics 2 and 3) so that we can read the text and see other details?
Is that red block the 'supply'? If so, it could be a conventional tranny rather than SMPS.

 

[A C Hunter]

Can you post bigger (not huge!) pics (particularly pics 2 and 3) so that we can read the text and see other details?
Is that red block the 'supply'? If so, it could be a conventional tranny rather than SMPS.

Text was in post one. Will re-tool photos.

 

[A C Hunter]

 

[alec_t]

The red block definitely looks like a conventional PCB-mount mains transformer. With a bit of luck you would be able to source a 110-Volt one with the same output ratings, physical size and pin positions. Then get busy with the solder-sucker and soldering iron .
Even if the pin positions weren't identical it looks as though you have enough copper area to drill holes and do a safe mod.

Edit: I suppose another option would be to replace the relays with 6V coil types?

 

[A C Hunter]

The replacement with a 110 is what I have been hoping for all along. Since they send out basically the same product in two voltages, what are the odds the transformer is the same one, only centre tapped for the 110? I may be able to open it and re configure.

What/who would be good starting points for looking for pcb mount replacement trans? How are those parts listed? What manufacturer? (to focus my Google search). I have been unable to track down much on XINCHANG

 

[alec_t]

what are the odds the transformer is the same one, only centre tapped for the 110? I may be able to open it and re configure.

I see only two pcb connections to pins of what I presume is the primary, so the chances of finding a centre-tap look slim . I doubt re-configuring is possible: the windings are probably potted in goo, with the primary innermost.

I'd make a note of dimensions etc then go to the website of a major electronics supplier (e.g. Farnell, Mouser, whatever you've got locally) and do a parametric search there.

 

[A C Hunter]

My late Father in law left me a bag of converters, the type used for calculators radios etc. If I find a dc (already rectified) 9 or 12 v, is there any reason not to press it into service? As I see it, we would get a doubly smoothed wave. Not sure what all is in the bag; hopefully will find something suitable.

Just found a wall wart marked 9v ac in that bag.... now to test and solder, if it works.

That would give me cold beer, AND time to find the correct part.

 

[alec_t]

That would give me cold beer

I see where your priorities lie . Just make sure the wall wart can provide the necessary current, or you could end up with hot beer!

 

[A C Hunter]

Your input is much appreciated. To be continued next weekend.....................................

 

[Mr RB]

Thanks for the photos it's definitely a normal power transformer.

Your under-PCB photo shows only two pins into the tranny and two pins out, so it should be very easy to replace that tranny with a 110v one.

Since you said the output was 14v AC when running on 225v AC, that looks like a common cheap 240v->12v transformer (that will output 15-16v at 240v in). You can replace it with a 110v->12v tranny of roughly the same size, very simply as there are only two wires on each winding.

If you have a 12v wallwart (plugpack) of the right size you can extract the tranny from that. Wallwarts are a good source of small transformers.

 

[alec_t]

@MrRB

that looks like a common cheap 240v->12v transformer

The label says 10V, 1.35VA.