Hello all! Grasping for straws here and hoping someone can help.
I found this digitech RP80 guitar effects pedal and seems pretty cool it if would work. Came with 12v power supply but nothing seems to power up. I took the PCB out and doesn't seem like it's getting power.
When I plug it in, the component right next to the power jack gets immediately flaming hot. My guess is that this component is bad, but I don't know what it is. It's labeled F1 on the board, and it's the only "F" component I can find. Everything else there seems obvious like "D" for diode, "R" for resister, "C" for capacitor, etc.
This component looks to me like some kind of power component, either a resister or some special diode. It only has 2 connections. It reads X050 1KKZ but I can't find reference to this part anywhere.
Continuity puts it at open. Ohmmeter puts it at 1 or .4 ohm depending on which way you connect probes.
Unfortunately it looks like a multi-layer board so It's difficult to know what is directly
It's entirely possible that some downstream part is fried or shorted. But the whole board looks pristine and nothing else seems to heat up. But this one get super-hot, too hot to touch.
Would be cool if I could identify this part and mabe fix it. Buying this on evil bay is like $30 so isn't worth any more effort than some simple parts hacks. I haven't tried yet but was thinking to just remove it and see if maybe this thing is just shorting to ground and starving power from anything else.
Any thoughts?
That component (F1) is a polyswitch. It acts as a kind of reset-able fuse to protect the board in case there is a short circuit. It has a positive temperature coefficient (PTC): when it is cold, its resistance is nearly zero, but when it gets hot, it will be thousands of ohms.
If you can see it getting hot, it means that there is a short circuit somewhere on the board, and it has done its job protecting the board from further damage.