Braumiser v2.1 sheild help needed

[bayoujeeper]

Hello all,
I am having trouble with a braumiser v2.1 board. When I turn the pump on I do not hear the relay (12v relay) click, and testing with a meter it is not closing the circuit. What is the best way to troubleshoot, or trigger the relay manually (jumping something, etc) to see if it is the relay itself are another part.
Also I notice In get 12v across the heater + and - regardless if the heater is on or not.
Any help would be greatly appreciated!

Dustin

 

[bayoujeeper]

When I turn the pump on and measure voltage across the ground and pin 8 of the arduino, I get 5v. Any clues? Could my relay be dead already?

 

[lael]

Post a pic of your soldering

 

[MastersBrewery]

Have you got LED's and so forth wired in?

 

[bayoujeeper]

MastersBrewery nailed it, I disconnected the LED's while trial fitting into my enclosure. Hooked them back up and BAM! Worky! Thanks!

 

[lael]

Nicely done MB!

 

[MastersBrewery]

Glad it was an easy fix, must be getting close to putting some grain in something and see how it goes! Good luck

MB

 

[bayoujeeper]

Getting super close to finishing my build but I got one last issue. I got everything mounted in my control panel and working, although the issue is the SSR is staying on whether the controller is calling for heat or not. If I disconnect one of the leads from the Braumeiser to the SSR + - the SSR light goes off. I measured the voltage across the + - of the SSR and it is 12v no matter what the controller is doing (heating, or sitting idle). The pump is switching on off, etc.
Any clues? Could this be in software? Any help is greatly appreciated! Ready to get a brew in on this!!

D

 

[bayoujeeper]

Also, when the board calls for heat the LED (NOT SSR LED) lights as it should and turns off as it should. It's the SSR led that stays on constant, unless one of the + - are disconnected.

 

[MastersBrewery]

It sounds like a short in the heating circuit, go over your soldering and check for a shorted circuit, ie solder joining two soldering points.


MB

 

[bayoujeeper]

I think you may on to something with a short.. If I take my meter and check continuity (with beep) for both heater terminals, I get a beep, wouldn't this indicate a short? I also get a beep if I check continuity between the 12v in + and heater + as well as 12v in - and heater - at all times. Could a bad transistor cause a short?

 

[Deevotronics]

Yes a bad transistor will cause a short. I say this without prejudice, but bad soldering is more likely to occur than a bad transistor. If you put your black lead of the multimeter GND (the negative lead from you power supply) and the red lead on your heater or pump output, using the buttons in manual mode should toggle the readings from 0VDC (off) to 5VDC (on). The software and hardware is well tested, so it is most likely a problem relating to construction techniques. The readings may be a bit lower (approx 3VDC) as the PCB designer has put the LED in series with the base pin of the transistor, thus reducing the drive signal by the forward voltage of the LED. This can vary from 0.9 to 2.3 VDC, so if you purchased LEDs with different parameters than those prescribed, you may not have enough base/emitter voltage on your transistor to turn it on.

 

[bayoujeeper]

I will check these when I get home today. How can I check the transistor if it is in fact the problem? Arrrgghh I hate to have to tear it apart since I have a 20x4 LCD soldered on the PCB, so I do not have access to the Transistors easily..

 

[Deevotronics]

Turn it all off then use the mutlimeter on "beep" setting (typically <40ohms). Remove the board and put your multimeter to beep, there should be no connection between any of the three pins of the transistor. If you hear a sound, check your soldering/wiring.

 

[bayoujeeper]

Turn it all off then use the mutlimeter on "beep" setting (typically <40ohms). Remove the board and put your multimeter to beep, there should be no connection between any of the three pins of the transistor. If you hear a sound, check your soldering/wiring.

Sorry Deevotronics, Do I need to desolder this transistor from the board to do this? Or can I just turn power off to the entire board?

 

[bayoujeeper]

If I put the meter on beep and touch any of the three leads of the transistor (With it still installed in the pcb) I get a beep, no matter which two I touch. Does that sound like a short somewhere or a bad transistor? I also get a beep touching the center pin and the negative post of the heater terminals.

 

[Deevotronics]

Sounds like short circuits to me. If you are getting continuity between +12V IN and HEATER+ constantly, thats a good thing as these pins are connected via tracks on the PCB. If you are getting shorts between -12V IN and HEATER - constantly, well that's a bad thing, as these should be connected via the transistor Q2 only when the Arduino tells them to be. You say the heater LED turns on and off correctly but the heater itself (or at least the LED on the SSR) stays on all the time. This tells me there is most likely a short between the pins of the Q2 transistor. When the Arduino output switches on and the heater LED on your board turns on, measure the voltage between the middle pin of your Q2 transistor and the -12V IN terminal. Easiest place to do this is black multimeter lead on the -12V terminal and red lead on the leg of the resistor R10 closest to the HEATER+ terminal. It should read at least 0.6V DC, I just measured mine and it was 0.8V DC. This is the minimum voltage required to turn on the transistor. If the heater LED attached to the PCB (but not the ssr LED) is turning on and you are reading 0 volts, this means the centre pin of the transistor is shorted to -12V IN. All it takes is a small (smaller than a millimitre) piece of solder to cause a problem like this. Without actually seeing the board its a little hard to diagnose, but Im fairly confident this will be your problem. Good luck!

 

[bayoujeeper]

Deevotronics,
Thanks for all of the help so far! I actually removed the transistor and replaced with another of the same kind. After soldering it in, I no longer had a short between the legs of the transistor. Hooked it all back up and turned it on, and I still have a LED on the SSR lit up.. I get a beep between 12v + and heater + as I should. I do not get a beep between the 12v - and the heater - any longer. With the board powered up I get 4.72 v between the heater + - and when I tell the board to heat manually, I measure 12.09v between the same two pins.
Between the 12v - in and the leg of the R10 resistor I get .7Vdc when the heater is on and .6V dc when it is not.
If I remove the uno and power up the board I get a beep between the 12v - in and the heater -, If I remove power I no longer get the beep, which sounds to me like a short.
Uggghhh! I went over my soldering and as it is not the greatest, I just don't visually see any shorts.

Also, Since I have not installed my element in my pot yet, I have tried plugging in different devices like a light and a hair dryer into the heater plug for testing and it is always on no matter if I am calling for heat or not.

 

[Deevotronics]

Don't use the beep setting when the board is powered up, you will get false readings. In that mode the multimeter is actually putting a little bit of current out the red lead and seeing if it comes back on the black lead, so if there is any other electricity flowing around the copper wires, well, you get the picture. Doesnt matter what sort of load you put in the heater plug, we need to fix the drive stage first, then you can dry your hair

With the board powered up in manual mode and the heater turned off, you should read 0V between heater+ and heater- because the transistor is not allowing any current flow, and you should get 0V on the R10 resistor because the Arduino output should be off. The fact that you are getting 0.6V at the leg of R10 when the heater is turned off tells me that something is wrong before the transistor. If the Arduino output is off but you still have 0.6V at your transistor, there is indeed a short somewhere, without seeing the board myself its hard to say where.

Below is a table of what you should be reading and different times. Leave the black multimeter lead on the -12V terminal, take the readings with red lead at the following points. Basically when the Arduino tells the heater to turn on, it puts 5V out onto the shield PCB. Some of this voltage is lost across the red LED, some of it is across the R10 resistor and the remainder is across the pins of Q2. With the heater output turned off, there should be no voltage anywhere along the test path, and therefore no current flowing through the SSR drive stage, so whatever is put out on the heater+ terminal should be coming back on the heater- terminal or at least fairly close to it. The following voltages are read directly from my system which works a treat, all your readings should be similar.

How about you post some detailed pictures of your PCB so I can actually have a look, a trained eye can pick up soldering issues much better than the un-trained eye.

Measurement Point Heater OFF Heater ON
Top leg of red LED 0V 5V (Arduino output voltage)
Bottom leg of LED 0V 3V (Arduino voltage minus voltage drop of LED)
Side of R10 furthest from Q2 0V 3V (same as above as they are directly connected)
Side of R10 closest to Q2 0V 0.8V (drive voltage for 2N222A transistor)
HEATER - terminal 12V 0V (transistor should be allowing current to flow)