Chosen Solution
Anyone one know where I can get my hands on a circuit digram of the thermostat board? The resistor (R101) next to the temperature variable resistor dial (VR1) has burned out and I need to know it’s specifications so that I can replace it. Any other work-around would also be greatly appreciated.
Update (10/13/2016) Hi again Jayeff and Cayette -thanks for your helpful answers. so this is where I am with the problem: I have no training as an electrical engineer, but I do understand circuit diagrams and am handy with a soldering iron. But I still might need a bit of help - I took a photo of the printed side of the board (yes it is a timer I think) and mapped out all the components (see image). The resistor colour band calculator was a great help and I have also listed the values. I did as Jeyeff suggested and took out the burned resistor R101, but the final colour was gone. Is there anyway you could analyse the circuit and take a pot-luck guess at the resistor value?If I replace it with a resistor of the wrong value, is there any danger? Many thanks again.
Hi David, If you are lucky then perhaps if you unsolder the resistor the value may be able to be discerned by the colour coding that may be remaining on the underside of the resistor. You will need to remove as much of the solder as possible without putting any pressure on the resistor leads. If you try to remove the resistor by melting the solder and pulling the resistor out of the thru-hole then most probably, because it will be brittle it will break and shatter and it will most probably be impossible to see anything. By removing nearly all of the solder, using either a solder sucker or solder wick hopefully you can get it to the point where it will almost fall out by itself if you turn the board upside down. Looking at your picture it seems that the resistor may have just failed (seems to have a ‘punch through’ look rather than a burnt out look due to excess current flow) so it may be that if you can work out its’ value that replacing it may be all you need to do. It might be prudent to get 2-3 just in case it is another component that is the real problem and the resistor is failing because of it. The other thing to do if the above doesn’t work is to draw the circuit by tracing all the tracks and components and writing appropriate values etc. This way you may be able to get a sense of what type of circuit it is. (I’m guessing it is mainly a timer type circuit with extras) and therefore you may have an better idea of what the value of R101 should be.
Color bands usually indicate the resistor’s value. http://www.digikey.com/en/resources/conv…
