ia06 Posted October 20, 2006 Report Share Posted October 20, 2006 Hi, I am new to this so any help would be appreciated. If you want me to post to some other category pls let me know. I have a circuit with relay, some resistors and capacitors, diodes and a transistor. The circuit has problem as the relay doesnt click and the dehumidifier doesnt start. I tried the relay on this circuit on another one and the relay works fine, so its not the relay that has issue. Diode seem to be ok they conduct one way (could there still be some potential problem even though they show working ?)I am not sure how to test the other components, I tried testing the resistors and they all seem fine and show me a value on digital multimeter. How do you test all the components on a circuit, i read it suggested that the components be tested outside the circuit, certainly with so many components they cant all be taken out of the board and tested ? what else should I check and what could be wrong here... thanks Quote Link to comment Share on other sites More sharing options...
audioguru Posted October 20, 2006 Report Share Posted October 20, 2006 You forgot to attach your schematic showing its part numbers and its supply voltage. Quote Link to comment Share on other sites More sharing options...
ante Posted October 20, 2006 Report Share Posted October 20, 2006 Hi ia06,Welcome to our forum,The problem might be outside this circuit, there might be a sensor (humidity sensor) which is faulty. As Audioguru mentioned; it would help a lot if you could post a schematic.BTW; a humidity sensor might look something like this: Quote Link to comment Share on other sites More sharing options...
ia06 Posted October 20, 2006 Author Report Share Posted October 20, 2006 ok I will post some layout /sketch. I dont have a complete schematic but I will post some stuff and pictures of the circuit soon.btw, the humidistat is external and is a mechanical one. when I tested the other circuit (the working one) the humidistat clicked and the dehumidifer worked. When I attached this circuit back, nothing. The relay on this one is good I checked it on the other circuit. There is one IC on this which I suspect , its 12C5028A (probably a re-programmable IC?). 1 Tanssistor is C556B4 caps (one of them is 47uf 63v, others are small ones)will post more details and pictures soon.Thanks for your help in advance. Quote Link to comment Share on other sites More sharing options...
ia07 Posted October 26, 2006 Report Share Posted October 26, 2006 Sorry I misplaced my password and the system here does not send password when you forget it, no email sent. so had to get another id. I couldnt find any circuit diagrams and am attaching some pictures of the circuit to start with.A few notesInput from the unit is AC 110/120vRelay tested is okTransistor when given small voltage on emitter and base it works and the relay clicks manually. so transister seems ok.I guess the diodes on the circuit are used to convert to DC voltage since relay is 24v DC. ?Checked the Capacitor, shows 54 volts DC across the big one. Quote Link to comment Share on other sites More sharing options...
ia07 Posted October 26, 2006 Report Share Posted October 26, 2006 attaching another picture, labels on this one are much clearer. If you need any other view/picture from another direction/angle let me know. whatever that will help clarify the circuit/PCB layout. let me know your thoughts pls. How do I troubleshoot the voltage across components. looking forward to hearing from you guys Quote Link to comment Share on other sites More sharing options...
ia07 Posted October 27, 2006 Report Share Posted October 27, 2006 upon further tests I can see that pin1 and pin8 of 12C5028A chip is not getting 5v so it can work as a timer. Quote Link to comment Share on other sites More sharing options...
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