what is this component?

[wellington1869]

What is this electronic component on this circuit board?  Is it an adjustable cap or resistor or etc? Should I stick a screwdriver in there and turn it and see what happens? Or is it something i really shouldnt mess with?




Its from a Nady wireless transmitter for guitar

[wap32]

I think that's an adjustable inductor, by inserting/removing the core in/from the coil you are changing it's inductance.
I'm not sure though, I could be totally wrong.

If you do want to mess with it and see what happens, just grab a sharpie and mark the position so you can set it back to the original setting.

[Findecanor]

It looks as if every other component on that board has a letter and number next to it. The letter should give an indication of what it is. Usually d = diode, r = resistor, c = capacitor, etc.
There is no letter?

My guess is that it is a adjustable resistor. I have seen many in that size.

[wellington1869]

I think that's an adjustable inductor, by inserting/removing the core in/from the coil you are changing it's inductance.
I'm not sure though, I could be totally wrong.

what would the inductor control?

If you do want to mess with it and see what happens, just grab a sharpie and mark the position so you can set it back to the original setting.

good idea

[wellington1869]

It looks as if every other component on that board has a letter and number next to it. The letter should give an indication of what it is. Usually d = diode, r = resistor, c = capacitor, etc.
There is no letter?

hmmm, no letter next to this one (or the other two black square boxes taht look like they're adjustable)

My guess is that it is a adjustable resistor. I have seen many in that size.

thats my guess too; i wonder what it controls.

in my dreams it controls tone (the nady loses some treble compared to a guitar cable), but of course thats wishful thinking. If its related to the frequency or the transmission, then i probably dont want to mess with it.

I suppose there's one way to find out.

[keyb_gr]

If I'm not mistaken, that should be a (possibly tuned) IF transformer belonging to the crystal filter behind it; it's used for impedance matching and (if tuned) improving far-off selectivity. The two slugs seen to the right are adjustable inductors (only to be changed with the right tools, for it's easy to crack the core), and the pink thing at the right is a trimmer capacitor; all of those should be on RF level.

None of all these are related to tone at all. Does either the transmitter or the receiver have a level control? Then crank that up for a bit. You obviously want an effective input level comparable to a real pickup at the guitar amp (keep in mind the signal has to be amplified, modulated (probably FM), demodulated and brought down to a suitable level). Other than that, you have to keep in mind that the input impedance of the transmitter and the guitar amp may be different, and so the interaction with pickup impedance may yield somewhat different results.

[wellington1869]

If I'm not mistaken, that should be a (possibly tuned) IF transformer belonging to the crystal filter behind it; it's used for impedance matching and (if tuned) improving far-off selectivity. The two slugs seen to the right are adjustable inductors (only to be changed with the right tools, for it's easy to crack the core), and the pink thing at the right is a trimmer capacitor; all of those should be on RF level.

None of all these are related to tone at all. Does either the transmitter or the receiver have a level control? Then crank that up for a bit. You obviously want an effective input level comparable to a real pickup at the guitar amp (keep in mind the signal has to be amplified, modulated (probably FM), demodulated and brought down to a suitable level). Other than that, you have to keep in mind that the input impedance of the transmitter and the guitar amp may be different, and so the interaction with pickup impedance may yield somewhat different results.

ah, thanks for the info.  yea, i wound up tweaking the treble on the amp and it sounds fine now. I didnt want to turn any knobs on that circuit board without knowing what they control.

[ch_123]

I once was poking around the guts of a 5.25" drive I had, and there were a few of those. For reasons that doubtlessly made lots of sense at the time, I turned the notch on one of them from its current position to the opposite one. It had the effect of causing the drive to keep spinning the motor continuously whenever there was no disk in the drive. Switching the thing back to the way I found it fixed it...

[Konrad]

I agree, my first guess is that it's an adjustable inductor. What it likely controls is fine tuning of a frequency, judging by its proximity to the crystal oscillator.
 
Yes, it could be a variable resistor or cap, or whatnot. It's adjustable because the combined tolerances on all the other components in the circuit can collectively knock the device out of expected operating range. Crystal oscillators also "drift" over time. One (or a few) "master" trimmers allows the manufacturer or repairman to easily calibrate overall circuit parameters back into normal operating ranges.  Often a cheaper alternative to using better parts with tighter tolerances.
 
If it's an inductor then it'll be hell to tune accurately with a metal tool because it will change value once the tool is repositioned or removed - you'll need a plastic or ceramic non-conductive, non-magnetic screwdriver head.  Or chunk of cardboard, or something.
 
If the gizmo works properly then it's pointless to adjust it. Unless you just want to experiment and learn.