Crossover help?

Thank you to everyone who contributed to this thread.

The strangest thing happened.

After checking the network as per imhififan's suggestion I had to go out, came back and plugged in the network.

Working!! wft?

Replaced the 2R7 still works, installed 56R still works.

Bolted everything back together installed fitted new tweeter and we have music.

First impressions admittedly with only 1 side done, the overall sound seems more open, there is definitely more HF on the upgraded side but with less glare. I thought the + upgrade reduced treble by using the 56ohm (about 1db?) and lowering the crossover from 3 to 2.5k

I've had to postpone the other side as when I was checking R values the 2R7 (which was installed) gave some odd readings then the lead fell out!

I'm now going to have to wait for a replacement before tackling the other channel.

Shame as my job tomorrow's has just cancelled due to covid.

Thanks again for your help.

Ian

Hi Thanks for the reply.

The crossover was removed completely.

The tweeter is still fine, checked.

I don't have any form of heat sink, i have previously soldered much smaller components with success.

The only items removed/replaced are resistors and a caps.

The continuity is from HF +/- which is assume to be the parallel resistor?

Regards Ian

How do you attach images? 

It links to a url rather than to a location on the PC.

I've been unable to discover the issue or post pics.

Looks like I'm going to have to build point to point external crossovers.😣

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

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

Thanks imhififan thats exactly what I was hoping someone could come up with.

Just checked the network as you suggested.

HF input terms OL

HF output terms starts at 0 climbs to 3.1

HF - to HF - 0.00

Surely its not possible the 3.3 cap stops that particular tweeter from functioning?

The new tweeters have just arrived but I can play with them until later this evening