Hey guys, im trying to figure out why my ceiling speaker has no output from the woofer or tweeter. I cannot seem to get a resistance at the main input speaker terminals but i did measure resistance at the woofer and at the tweeter wires individually and everything seems to be OK. Ive done a little bit of troubleshooting on my own and when i was probing the negative terminal in combination with any component (PTC fuse, the capacitor, and any of the resistors) on the crossover i get no continuity what so ever. However, when i take the same model speaker but a fully working one and i probe the negative terminal in combination with any of the components listed above i get continuity. What section of the crossover would cause a no output condition? I've been toying with the fact that its the PTC resettable fuse but i am unsure if its used to only protect the tweeter or if its used to protect the entire design.
I checked all the resistors and the values are as follows
25w2ΩJ=1.5
25w2ΩJ=1.5
10w2.2ΩJ=1.4
10w2.2ΩJ=1.4
10w2.7ΩJ=2.8
25w2ΩJ=1.5
25w2ΩJ=1.5
10w2.2ΩJ=1.4
10w2.2ΩJ=1.4
10w2.7ΩJ=2.8
Checking the components in circuit is meaningless unless you have the circuit digram and can work out what you would expect to measure.
The PTC is quite small so will only be there to protect the tweeter. The bass driver will be in series with the inductor, but the large resistors are also implicated because the bass sensitivity is adjustable ±3dB.
The tweeter is in series with the capacitor and PTC, with most likely the small resistors forming a ±3dB attenuator.
From the manufacturer's description I am guessing that with the sensitivity of the bass driver set to +3dB you should be able to measure with a multimeter on Ohms ~4Ω across the input terminals, ~6Ω at 0dB and ~8Ω at -3dB.
The PTC is quite small so will only be there to protect the tweeter. The bass driver will be in series with the inductor, but the large resistors are also implicated because the bass sensitivity is adjustable ±3dB.
The tweeter is in series with the capacitor and PTC, with most likely the small resistors forming a ±3dB attenuator.
From the manufacturer's description I am guessing that with the sensitivity of the bass driver set to +3dB you should be able to measure with a multimeter on Ohms ~4Ω across the input terminals, ~6Ω at 0dB and ~8Ω at -3dB.
thank you so much for your input that is very informative and a good starting point for me. I checked the resistance on main input terminals with the tweeter & woofer switch in all positions but i still cant get a reading. Individual readings off the woofer is 5.2 ohms and individual reading of the tweeter is 3.5ish. Could a bad switch on the TW / midbass cause the no output condition?
There's a break in continuity somewhere. Because the fault is affecting both speakers it is ahead of any crossover circuitry. Check that the printed circuit isn't cracked around the input terminals.
good call on the crack in the PCB! i thought it was just a scrape but turns it it was a hairline crack so i restored that by lightly scraping both sides the trace and soldering the hairline crack together. Also had to fix a trace by soldering a 16gauge wire from the positive post to the 25w2ohmJ end lead closest to the smaller 10w2ohmJ resistors. All is good now 😁 Thank you again for the help
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