I have a trc-975 that has a crackling type of noise in the right speaker. It's not a huge distorted noise or anything - just a small crackly/buzz sound. When I have the loudness button activated it gets 10 times worse than when it is off. In fact, it is not hardly noticable when the loudness is off.
Is there a way to know if the speaker is blown and needs replaced or if some of the controls need a deoxit to clear up the problem?
I guess I could change the speakers from right to left to see if the problem stays with the speaker. I am just wondering what a good first plan of attack would be to solve this.

See my PC-55 "I found Bass" in the boombox chat section. My right speaker on my PC-55 developed a nasty pop at 1/4 volume with mid to mid-high levels of bass. I replaced speakers with stronger ones because it usually means the coil is somehow gone given that everthing else is intact. Switches aren't usaully the suspect, a problem with the amp would be the other.

I'm no expert however what your describing is a classic sign of a blown speaker, it doesn't sound like a switch or pot problem. The test you described is a simple way to verify a speaker problem and remove the possibility of anything else.

a blown speaker cant handle any strong bass --

so most likely -- thats it.

in fact - as soon as i get any Uncle Ed box --i disable the loudness buttons and bass controls -

THEN - they sound fine

in my experiemce blown speaker do nothing at all, and iv'e blown dozens .lol you may have intermittent contact in the loudness switch,or just a damaged speaker which is not blown yet.either way i would reccomend cleaning the loudness switch if you havent yet.

quote:

Originally posted by jvc floyd:
in my experiemce blown speaker do nothing at all.

I consider that a fried speaker.

floyd - i meant that for speakers that only need refoaming.

quote:

Originally posted by jvc floyd:
redbenjoe ,a speaker with the foams rotted should not be played at all if you want to save the speakers.

floyd - THANKS
i guess its headphones ONLY --till they get foamed

O.K. so it seems to most likely be a blown/damaged speaker. I think I am going to try to deoxit the loudness switch first and check all the speaker connections - but I am guessing I am going to need a new woofer. Is there a way or a place to get this one repaired and still keep the original white speaker chrome cone look?

well what i have seen in speakers blowing is a couple of things 1: coil burns too much power 2: speakers get out of alignment coil rubbing againt magnet in a sideways movement if you look very closely the frame is bent a bit 3: it siezes inside where there is no movement at all when they get to that stage there is some sound but it turns into a tweeter if its in a have stage there is movement but very little and as soon as you apply some loudness or a lot of bass you will hear a lot of crackling noises it is actually it is rubbing inside coil againt the magnet buildup of moisture and rust forming hope this helps

It sounds pretty good at normal volumes without the loudness switch - sometimes there is no crackle at all when playing radio or tape and on some songs I can even turn it up really high. But as soon as I push the loudness switch the crackle kicks in even at low volumes it never seems to go away. With the line in/ipod there is always a crackle.

ok - wait for our pros to confirm this theory ::

the digital ipod may be calling for a deeper base response than your FM radio --
so i still say -- your electronics may be fine --and your speaker needs foam

ok floyd - you are probably right - hope so -

because its so much easier to spray stuff than to fix stuff

Sounds like a coil rubbing against the magnet.
usually the sign of a speaker thats on its way out.
Swap left for right and see what happens to rule out the pre-amp or amp chip or dirty contacts or pots.

You can connect some speakers through the ext. speaker jacks. You don't have to swap the internal ones. Of course try to load the amp with the same ohm rating of the internals.
Looks like a mechanical problem around the speaker.
Be carefull while operating the unit with midded burned speakers (in case they are burned), since its ohm reading could be lower then the expected by the amp. That's because coil's wire loose insulation while burning, and that lowers the resistance
That continues until, the coil opens, or the amp get damaged while driving the damaged speaker.

quote:

How do you know when a speaker is blown?

When it doesnt produce sound anymore ...

would be my guess