Hi all
Thanks in advance if anyone can assist.
yesterday I started the process of upgrading PMC FB1 to FB!+ crossovers.
I desoldered 2 caps and 2 resistors and replaced with close tolerance items as specced by PMC.
I now have no HF output.
I've checked for tweeter function, good.
Checked for dry joints/breaks, nothing obvious.
Checked resistor values, good
Checked inductors, good, I think.
Removed and replaced back to stock, no change
Checked continuity up to and after caps, good.
Can anyone help with diagnostics on a crossover using a basic mm?
Its driving me nuts!!
I will try to get pics from the phone to attach later
View attachment FB1+.pdf
Thanks in advance if anyone can assist.
yesterday I started the process of upgrading PMC FB1 to FB!+ crossovers.
I desoldered 2 caps and 2 resistors and replaced with close tolerance items as specced by PMC.
I now have no HF output.
I've checked for tweeter function, good.
Checked for dry joints/breaks, nothing obvious.
Checked resistor values, good
Checked inductors, good, I think.
Removed and replaced back to stock, no change
Checked continuity up to and after caps, good.
Can anyone help with diagnostics on a crossover using a basic mm?
Its driving me nuts!!
I will try to get pics from the phone to attach later
View attachment FB1+.pdf
A schematic will help us devise test procedures, such as measure at x,y and expect z result.
Meanwhile you could check resistance across the driver.
Meanwhile you could check resistance across the driver.
Your testing should find the issue.
Is the PCB double sided, check both sides for good joints and solder whiskers bridging tracks.
If you verify all wiring connector, wire to pcb, through pcb, pcb connector, cable to loudspeaker that should do it.
I am not sure if you can measure the capacitors, you could try carefully re flowing their joints and not letting the iron dwell to long to reflow the joints. The same goes for the pcb push on connectors.
From your attachment they are rather close together so look for anything touching or shorting around the outputs.
It may be one of the replacement caps was bad, but as you replaced the originals as a sanity check that's not it?
If the issue doesn't manifest itself easily, gently move the cables around to see if they are intermittent.
Frustrating to say the least.
Good luck.
Is the PCB double sided, check both sides for good joints and solder whiskers bridging tracks.
If you verify all wiring connector, wire to pcb, through pcb, pcb connector, cable to loudspeaker that should do it.
I am not sure if you can measure the capacitors, you could try carefully re flowing their joints and not letting the iron dwell to long to reflow the joints. The same goes for the pcb push on connectors.
From your attachment they are rather close together so look for anything touching or shorting around the outputs.
It may be one of the replacement caps was bad, but as you replaced the originals as a sanity check that's not it?
If the issue doesn't manifest itself easily, gently move the cables around to see if they are intermittent.
Frustrating to say the least.
Good luck.
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