Hello everyone!
I've been trying to fix a FM receiver and I found this weird resistor. I've found it the receiver it's a blue box that says r22 so I would think it will be 22 ohm but it measures sort circuit. Is this some special kind of resistor or it is faulty and that's why it measures sort circuit? You can see it in the top right in the photo.
I've been trying to fix a FM receiver and I found this weird resistor. I've found it the receiver it's a blue box that says r22 so I would think it will be 22 ohm but it measures sort circuit. Is this some special kind of resistor or it is faulty and that's why it measures sort circuit? You can see it in the top right in the photo.
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We have been guided to look at the blue component marked R22 at the extreme top right of the image and not the preset inductor outlined in red.
If its the aqua component at the top right, it's likely a 0.22 ohm resistor. It would measure as a short circuit on just about any DVM.
It is, ofc.
@VaggelisDer It changes the inductance by screwing the powder core in or out of the coil within the metal screen. In a tuner these are used to tune the receiving bandwidth, suppress mirror frequencies etc. If you mess with them you'll have a hard time to get the tuner to the former sensitivity and bandwidth work again properly. Don't screw yourself with these! 😉
Yeah I meant the one at the top right sorry for the quality of the photo I didn't see the red box. If it is a .22 ohm resistor why would it make sense to have almost sort circuit the antenna to ground. This FM module is not recieving any signal or noise it's completely muted.
Yeah that might be right, that's why it measures sort circuit to ground. Unfortunately my multimeter doesn't measure inductance but thats probably it. I guess I have to dive in deeper into why it does not receive signal.
It makes a lot of sense in fact, to short an antenna to ground at DC - first line of protection from ESD and lightning-transient damage - todays RF ICs are often exotic semiconductors much more sensitive to static than silicon devices... Of course at RF it would not be a short circuit at all.
Depending on what else is connected that does interact with it. It's very likely to limit the bandwidth or part of an oscillating circuit, an impedance transformation could also happen there.