I'm looking at the square black device with three connections, labelled U4. It looks to me to have a hole in it which suggests it is , lets say, goosed. The hole suggests that its works have exploded.
I can't fully make out the number on it, but it looks like 78**** and MAY be a voltage regulator.
IF it is, it was responsible for supplying a regulated voltage to the electronics. Does the burned resistor connect to this device? If so which terminal, and where does the other end of the resistor connect to?
The black unit on the corner of the board is a transformer, apparently providing a 12 volt supply to the nearby diodes and capacitors, so there should be around 15volts DC there.
NB> The blue part is a capacitor and should NOT have continuity, but you can't test it in circuit as you don't know what's wired across it.
Please realise that we are clutching at straws trying to fix a board like this but I do admire your tenacity. How much is a replacement board?
U4 and catching 78 was a good spot. Eyes better than mine by the looks of it. U1 has a circular depression in it, must have had this in mind when glancing over U4. So easy to overlook things on these.
With regard to supply regulated voltage, what the burned resistor connects to, black unit in the corner being a transformer15v there, where things lead etc are all good tangible things to check.
With regard to clutching at straws lol. I understand. It was good to narrow the problem down to the PCB, I cant see it being anything else. Just thought I could perhaps fix the PCB, and I like doing this kind of stuff as well.
Thanks for the time, help and patience.
Have you actually measured the value of the resistor you seem the think is faulty?
Whilst it has clearly got a bit warm...
Is it actually open circuit?
I would suspect something else has failed causing the resistor to get a bit too warm...
Resistors are generally quite robust components that can take a bit of abuse...
And I would have thought there would be more visible damage on the PCB itself if a resistor failure was the primary problem..
As Geoff said not all components should show a continuity with a multi meter..
And other components are pretty much impossible to test whilst still in circuit due to all sorts of parallel paths..
especially if you don't have the manufactures data to check with.
What have you actually learned about the function of the PCB...
Do you know what all the the plug connectors pins should be doing?
Functions, expected voltages in/out etc...
:C
I’m not an electrician with 14k posts on an internet forum. So being descriptive, simplifying technical language, pointing things out, linking information to read, giving me tangible things to do that I’ll understand; is much more helpful than being inpatient, patronising and condescending.
In your first post, you said buy a new dryer. In your second post, essentially, more hassle than its worth and I'm not willing to help. I’m clearly not here to waste peoples time and I’m willing to learn, so if youve got no appetite for it, don’t reply; why are you replying. Look at all the other posts; people want to diagnose, once theyve diagnosed, they want the fix. For some, that might be just replacing the part, others might not even bother and just buy a new appliance. For me, because I like fixing things and learning, I wanted to know more about possibly fixing this PCB. If you think something else broke this PCB, beside the interference filter, we could have explored it, but you didnt, (and there doesn’t appear to be anything, beside that filter). If you were willing to teach about PCBs, I was willing to learn. What have I learned about PCB’s ? not much lol ! But thats what you were saying wasnt it, and is it ever wonder with your posts. 'Learned’ obviously stuck out for you, replace it with ‘learning’ if you’d feel better.
However, I know more than I knew last Tuesday. My knowledge of wiring and parts inside condenser dryers has improved. I’m in a better position to diagnose and fix a dryer in future. So posting here hasnt been entirely useless because I've learned bits from Geoff who's been good enough to try and help out.
With regard to the PCB, I’m ‘LEARNING’. Theres a lot to learn in electronics, theres gaps in my knowledge. Sure I could spend £80 on another, or buy another £200, 300, 750 pound dryer. But what if I could buy a fivers worth of resisters, fix it, and learn a thing or two along the way……. I don’t get any negativity or impatience towards this. If you cant be arsed helping or furthering my knowledge, don’t reply. To answer your question, yes the resistor is courgetteed, its been tested. Geoff pointed out U4, along with various other tangible things to check. If I replace R4 and U4, will I fix it, who knows, I'll test further, maybe try it out, I’m learning……..
Wish me luck messing around with the PCB. I'll wish you luck with your next 14k posts.