Electrical heater controler

[tomalamix]

Hy guys!

Today Im posting a few photos from my electrical heater controller.

The thing is that it turn on just right but as soon as the backlit comes in when I press the UP / DOWN temperature buttons the displays fades at such a point that the display fades completely progressively in 1-2 secons, its noticeable the display fading away, then the backlit stays really weak and the power LED goes out.

Everything comes back to normal after a 10 seconds that is the time the backlit should remain ON while i change the temperature setting.

Besides this, as long as I don't touch the temperature setting it works, I can see the temperature in the display (because the backlit is not turned ON).

Below I attach a picture of the PCB from where you can see several capacitors, all JACKCON









I've took one out, the 4.7uF 100V that is near the small yellow transformer (that feeds the backlit among other things) and it reads 4900nF , 10ohm for ESR and Vloss 4.5%.

The value seems OK but im not sure about the ESR and the Vloss, I'm not a electronics expert but i would like to repair this unit, so i think I can count with your expertise by looking at the PCB photos and giving me some inputs, all are valid.

I have several other electrical heaters becoming like this one: when the backlit kicks in the displays fades completely.

[sam_sam_sam]

Re: Electrical heater controler

Hy guys!

Today Im posting a few photos from my electrical heater controller.

The thing is that it turn on just right but as soon as the backlit comes in when I press the UP / DOWN temperature buttons the displays fades at such a point that the display fades completely progressively in 1-2 secons, its noticeable the display fading away, then the backlit stays really weak and the power LED goes out.

Everything comes back to normal after a 10 seconds that is the time the backlit should remain ON while i change the temperature setting.

Besides this, as long as I don't touch the temperature setting it works, I can see the temperature in the display (because the backlit is not turned ON).

Below I attach a picture of the PCB from where you can see several capacitors, all JACKCON









I've took one out, the 4.7uF 100V that is near the small yellow transformer (that feeds the backlit among other things) and it reads 4900nF , 10ohm for ESR and Vloss 4.5%.

The value seems OK but im not sure about the ESR and the Vloss, I'm not a electronics expert but i would like to repair this unit, so i think I can count with your expertise by looking at the PCB photos and giving me some inputs, all are valid.

I have several other electrical heaters becoming like this one: when the backlit kicks in the displays fades completely.

I would say that if 4.7uf at 50 volts has a value of 10 that is way to high now if it at 100 volts or more this value might be still a little bit high the best thing is if these capacitors are not brand name capacitors replace them for good measure ( I would highly recommend that you replace this capacitor first and see if you still have this issue )

**** Use caution doing this *****

Here is something you might try if you can find the power supply rails for the heater controller portion ( this will probably be a voltage around 5 volts or so it might be a little bit higher than this ) of the circuit and can power it up from there and just operate the the controller with out the heater element and see if you have the same exact issue that will help you narrow down what part of the circuit is giving you this issue


****************************

But my guess is that there is an issue with the switching power supply portion of the circuit board and this is why when you put the heater on the power supply rails are draining down completely or nearly that way and this might be because of a bad capacitor on the switching power supply regulator or something is wrong with the controller part that turns on the heater element

I have one question for you and that is this what device turns on the heater element is it a relay or some type of ic device of some type

I hope this helps you figure out what going on with this device

[tomalamix]

Re: Electrical heater controler

Hy sam_sam_sam!

Thank you for your input.

I dont have a power supply to put 5V inside the controller rail and at this moment, but i can explore that

About the heating element, its clearly a relay, it's covered with that hot glue that you can see in the picture, but that one is working properly, it turns off the heating element when the temperature reaches the desired temperature and turns on when the temperature is dropping too much.

The appliance works 100% IF i dont touch the buttons that makes the back lit come on, if i do that it seems the power is all drained out to the back lit and can't hold the back lit on nor the display - it remains like that for 10-15 seconds (its the time that the back lit should stay on)

thank you

[sam_sam_sam]

Re: Electrical heater controler

Then the most likely issue is that capacitor that you checked by the switching power supply transformer because if you look closely at where this capacitor is it should be very close to an ic chip that is some type switching power regulator or a off line switching device

One thing you can try is disconnect the back light and see if does the same exact thing if dose then you have a switching power supply issue if does work correctly with out the back light then you could have an issue with the back light or still have a switching power supply issue

[CapLeaker]

Re: Electrical heater controler

Can we see some high res pictures?

[R_J]

Re: Electrical heater controler

180 x 83 pixels is too small to be usefull

[Per Hansson]

Re: Electrical heater controler

^^I uploaded the originals to the OP.

[tomalamix]

Re: Electrical heater controler

Sorry, i thought i did uploaded those correctly. I have the controller disassembled, if you need some closer picture to some area please tell me.

Meanwhile I'm going to try changing that capacitor 4.7uF 50V that is reading 4900nF, 10ohm for ESR and Vloss 4.5%. Unfortunately will be a JACKCON again, my local eletronics store doesnt have another brand. Later and if the problem is solved I'll go for Panasonic or Rubycon.

If you guys see anything else worth to test please tell me, I'm getting used to test my new ESR02 Pro

[Per Hansson]

Re: Electrical heater controler

Sometimes supplies like these use a capacitive dropper: then the value of the yellow X class capacitors is very important (that it has not degraded in capacitance value).
I'm not sure if this is such a device, I do see a small transformer so maybe not, but won't hurt to chuck (as long as it is discharged lol)

[tomalamix]

Re: Electrical heater controler

Sometimes supplies like these use a capacitive dropper: then the value of the yellow X class capacitors is very important (that it has not degraded in capacitance value).
I'm not sure if this is such a device, I do see a small transformer so maybe not, but won't hurt to chuck (as long as it is discharged lol)

Ok, Im going to remove both just now and will write the result right away:

Ok, both rated for 275V, one is 0.47uF, while testing gives me 259.7nF with 3.8ohm ESR. Almost half the capacitance it should have.

The other is a 0.15uF and reports 1005pF, no ESR value (strange...). The reading is wayyyy too low. Should i do some other testing to be sure? I've disconnected only one leg of the capacitors, discharged both and done the testing.

[CapLeaker]

Re: Electrical heater controler

I'd change the 275V 0.47uF and the 4.7uF 50V and see what happens.

[tomalamix]

Re: Electrical heater controler

I'd change the 275V 0.47uF and the 4.7uF 50V and see what happens.

Ok, i'll go for those two, but what about the 0.15uF that reports 1005pF ? It's not worth to swap too? Am I doing something wrong? Sorry for the silly question..

[Per Hansson]

Re: Electrical heater controler

Yes you should change them both, and when you get the new ones test them on the meter:
Because it needs to be properly calibrated to be able to show values this low with confidence, so it will be a good test for the meter too

[tomalamix]

Re: Electrical heater controler

Ok, i've tested the ESR02. The new capacitor 4.7uF 50V is reading 4800nF, 4ohm for ESR and Vloss 3.5%. It's not perfect but better than the previous.

The new 0.15uF reports 145nF, no ESR value again and no Vloss. At least the capacitance is in the right range.

The 0.47uF testing gives me 480nF with 4.8ohm ESR, no Vloss value too.

Everything assembled and the unit worked properly!! But only for...20 seconds...

The back light was on, the power LED was on and I was changing the temperature setting with everything visible in the LCD, but all that stopped working in a few seconds and never came back again. Now I can't turn on the unit, no LED, noe LCD, no relay kicking in, nothing...

I've opened everything again but I can't see anything out of the place, i'm lost now..

[sam_sam_sam]

Re: Electrical heater controler

The 4.7uf@50 volt is still a little to high it would be better if was 1.something to maybe 2.something but this might be pushing it depending on what the circuit is requiring ( mind you this is a new capacitor for this value )

I do not have any 0.47uf you do have the voltage listed 4.8 might be a little high as well I have to look and see if I have any of this value

Have you found a switching power supply regulator on this board yet if you do list the part number for it so I can look up the data sheet for it

[CapLeaker]

Re: Electrical heater controler

Can you upload new straight shot high resolution pictures? Maybe we can see something where the smoke came out.

Check for DC voltage at the bridge rectifier next to the 0.47uF cap. Recheck the other cap for proper orientation. Check for open or higher in value resistors than spec. Bad diodes… etc.

[tomalamix]

Re: Electrical heater controler

Ok, i've uploaded the photos, I don't have any other camera then the phone so this is waht I can send. Searching around I can't see anything out of ordinary, nothing roasted, not even that typical smell is present.

Some notes about the photos, I've rebuilt a track that i've destroyed near the polyester capacitor, but it was working before so the problem isn't there. Another thing is that the new polyester capacitor is 310instead of 275V if that matters.

About the rectifier, I see there a BC B10S just after the polyester capacitor., is this a rectifier? This means something to you? Is the one near the right yellow capacitor.

Ok, meanwhile I've been reading around and this BC B10S is a two in one diode, it rectifies the voltage from AC to DC, right? Instead of having two separated diodes doing that there is this BC B10S.

Done some testing between the rectifier poles, the ESR02 gave be me a thing like: 2* >| (DIODE SYMBOL) \ 2 >| 3 >| 2 \ Uf= 2,23V 700mV

On the other "channel" gave me 2* >| (DIODE SYMBOL) \ 2 >| 3 >| 2 \ Uf= 700mV 2,23V

[eccerr0r]

Re: Electrical heater controler

I don't know where the "BC B10S" you're working with is on your board.

I can see a BR3 designator on the PCB and that's a bridge rectifier that should contain 4 diodes. Having 4 pins I'm not sure how you got it into a 3-pin avr transistor tester?

Hmm...capacitor dropper psu...

[R_J]

Re: Electrical heater controler

B10S must be the numbers on the bridge rectifier BR3, this bridge contains four (4) diodes.

[tomalamix]

Re: Electrical heater controler

Well, I've tested it, i've connected the 220V on the line of the PCB and measured the output on the B10S. There is 2.4V, i think its working properly.

Meanwhile I've detected a pin without proper grounding, the wire that connects there is not conducting properly, I'm going to change this wire and test again everything, i'll keep you guys posted