2. speakers
  3. 172832-168368

Crossover help?

Hi to all I'm hoping someone might be able to help.

I've tried to upgrade components within my crossover and now have no HF signal.

The tweeter checks out.

I've searched for bad joints , shorts etc but can find nothing obvious.

Today I've pulled the upgraded components from the Hf circuit but still have nothing.

Using a continuity test its all good up to the main cap and after back to the terminal.

I do get a bleep from both terminals so assume thats the parallel resistor.

I'm at a loss as to why its gone completely dead.

Anyone got ideas how to check the network front to back with only a basic multimeter?

 

Thanks in advance if someone has some ideas

Regards Ian

 

notdeadyet
notdeadyet OP
23 posts
 

Hi and thank you for the replies.

The speakers are PMC FB1 they are well known for being overly bright.

Its been my intention to follow the + upgrade for years but had never found the crossover changes until recently. . I got hold of the layout with values and found a photo of the upgraded network.

The only changes are replace the 3.0 cap with 3.3 and add a 56ohm resistor.

I decided to change the ageing cap on the LF and resistors as a what the heck while I'm in there.

I removed the network, removed HF resistor, positioned the new, removed cap, positioned new, same for LF positioned 56ohm flipped it over and soldered everything in. clipped tails and reinstalled network, no HF.

Removed network desoldered 1 end of 56ohm, checked no change.

Checked tweeter operation, working.

Removed network checked for shorts, poor joints and poked around with continuity tester, nothing obvious.

Removed HF parts refitted originals checked, no change.

Since then I've been poking around trying to find anything amiss.

I've posted some pics on my system

 

sns
3,334 posts
 

I don't see your system. Look at this thread,https://forum.audiogon.com/discussions/tweeter-blown-or-crossover-how-to-check

sns
3,334 posts
 

I searched and saw picture of upgrade, you have circuit board, per grannyring likely damaged pad or trace. Solder pads easily damaged in removal of original components, need proper desoldering equipment, don't force anything. Believe me I know from experience.

 

Above if you're 100% sure drivers working.

notdeadyet OP
23 posts
 

I used a sucker and wick, the tracks are pretty robust.

I get a a bleep up to and away from the cap, can't test the cap but neither new or old refitted made any difference.

I'll play around again tomorrow see if I can find a break.

Really struggling with this one.

Any idea what reading I should get from the coil?

Its showing 0.9 .71mm

sns
3,334 posts
 

Did you read that thread I mentioned, I find it hard to believe your tweeter not fried or board damaged. You have to make sure you haven't damaged voice coils, pretty fragile. Multimeter readings often of no use when everything in circuit. You have to put battery across speaker terminals, or send signal directly to tweeter bypass entire crossover, remove all crossover wires from tweeter terminals and test. If tweeter working, circuit board bad. Unless fried inductor.

 

You may have to find local tech or send board back to PMC. Too difficult to troubleshoot by forum. I just have to believe you've fried something.

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