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Imf crossover problem

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09mike69

New Member
Just acquired these but they are the early version with a slightly different x,over layout to tls 80.
No luck from falcon regarding x,over schematic.
The problem is no sound output to the tweeter and super tweeter.
The crossover have been mucked about with and the tone switch has been removed.
Any help /advice welcome
Mike
 

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Wow those cabinets look great!
But yeah someone has already made repairs/modifications, hopefully someone will recognize which version of the crossover you have
 
beekeo said:
Wow those cabinets look great!
But yeah someone has already made repairs/modifications, hopefully someone will recognize which version of the crossover you have
Click to expand...
Thanks, yes cosmetically they're in good condition bit they have been mucked about with and some of the speaker unit's aren't original.
Just waiting for a price for new cross overs from falcon acoustics but in the meantime hoping to source a pair of tls 80 xovers.
My first experience with imf and I think it's going to be worth putting money into them to get them right.
Thanks
Mike.
 
Nashou66 said:
this thread has lots of corssover schematics for the various IMF models.

https://audiokarma.org/forums/index...ossover-schematics-rebuild-assistance.704345/

Athanasios
Click to expand...
Thanks, checked there but no luck.
The info I have so far is that mine are the early transmission electronics ltd MDKT version, same speaker layout as the tls 80 only different X.O's.
I've spoke to falcon but he doesn't have a schematic.
If anyone has a pair and wouldn't mind taking a photo of the X.O that would be very helpful.
Cheers
Mike.
 
With out knowing the ohms of each driver id keep the crossover and IMF intended. On later models and even within the same line they would use different value speakers and adjust the cross overs accordingly for the speaker they used. So basically thee are many iterations of IMF crossovers for the same speaker . Id trouble shoot the crossover to see where the blockage is. Have you tested if each speaker is working directly at the speaker?

Athanasios
 
I agree with Nashou about using a multimeter to test all of the components to help determine where the fault lies. Even though the caps have been replaced it looks like clean work to me.

I would also pop out the terminal cup on the back, it could be that the switch was removed but the rest of that circuit is intact
 
Nashou66 said:
With out knowing the ohms of each driver id keep the crossover and IMF intended. On later models and even within the same line they would use different value speakers and adjust the cross overs accordingly for the speaker they used. So basically thee are many iterations of IMF crossovers for the same speaker . Id trouble shoot the crossover to see where the blockage is. Have you tested if each speaker is working directly at the speaker?

Athanasios
Click to expand...
Yes, tested the tweeter in another speaker and it worked fine. I also tested another working tweeter in the imf and it didn't work.
So it seems the X.O is the problem,
It also could be that they were like this since they were "modified" .
Thanks
Mike.
 
beekeo said:
I agree with Nashou about using a multimeter to test all of the components to help determine where the fault lies. Even though the caps have been replaced it looks like clean work to me.

I would also pop out the terminal cup on the back, it could be that the switch was removed but the rest of that circuit is intact
Click to expand...
No circuit board behind the terminal it could have been removed with the switch.
With the tone control removed would that affect the sound output to the tweeters ?
Or would they work as intended.
I've heard that people have had the controls removed as a mod as they believed it dirtied the signal, This I don't know.
Thanks
Mike.
 
yeah I'm not sure what the elimination of the tone board would do to the circuit on your speakers since we don't know what it was like originally

from the photos I took on my TLS 50's, the signal splits at the terminal, one pair of wires heads directly to the main crossover for the woofer and mid, and another set of wires go the tone board.
then I can't tell if the tweeter and super tweeter continue to share a connection after the tone board or if they don't separate until the main crossover board, there's at least 4 wires going into the cabinet, but it's an odd angle and I can't be sure there wasn't more.

if your tone board was removed, then the tweeter connection to the main crossover was switched from the tone board to be directly on the terminal -- I would check these connections first

when you swapped tweeters in and out, were they soldered in place or did they have crimped-on quick connectors?
 
beekeo said:
yeah I'm not sure what the elimination of the tone board would do to the circuit on your speakers since we don't know what it was like originally

from the photos I took on my TLS 50's, the signal splits at the terminal, one pair of wires heads directly to the main crossover for the woofer and mid, and another set of wires go the tone board.
then I can't tell if the tweeter and super tweeter continue to share a connection after the tone board or if they don't separate until the main crossover board, there's at least 4 wires going into the cabinet, but it's an odd angle and I can't be sure there wasn't more.

if your tone board was removed, then the tweeter connection to the main crossover was switched from the tone board to be directly on the terminal -- I would check these connections first

when you swapped tweeters in and out, were they soldered in place or did they have crimped-on quick connectors?
Click to expand...
Tweeters are soldered in place, the hf2000 I tested in situ, defibrillator style as I assumed they were fried. But no they were fine.
What I did notice is when I removed the mid and bass units I could faintly hear the hf2000.
It doesn't look like there was anything removed from the X.O intact the only dodgy soldering is where the replacement visiting caps are. And the caps marked Professional speaker, I don't know if those are original either I've only seen elcaps in the X.O's I've seen.
Thanks
Mike.
 
Id start taking continuity tests from the inputs tot he crossovers etc.

Also with everything connected, what is the ohms between input terminals?

Anyway here is a tis 80 cross over schematic,

25235981785_21f3698ede_h.jpg


25235981815_2aba64629c_h.jpg



Maybe compare yours and see what you can figure out?

Athanasios
 
Last edited:
09mike69 said:
Tweeters are soldered in place, the hf2000 I tested in situ, defibrillator style as I assumed they were fried. But no they were fine.
What I did notice is when I removed the mid and bass units I could faintly hear the hf2000.
It doesn't look like there was anything removed from the X.O intact the only dodgy soldering is where the replacement visiting caps are. And the caps marked Professional speaker, I don't know if those are original either I've only seen elcaps in the X.O's I've seen.
Thanks
Mike.
Click to expand...
Meant visaton caps.
Nashou66 said:
Id start taking continuity tests from the inputs tot he crossovers etc.

Also with everything connected, what is the ohms between input terminals?

Athanasios
Click to expand...
I'll double check when I get home.
 
Tweeter measured 5.4 ohm super tweeter measured 4.9
I had to use the X.O connection to measure the hf2000 because I can't remove it from the front baffle.
I also lengthened the speaker wire from the tweeter of another speaker and connected that the tweeters via the X.O on the imf and they both worked.
Don't know if this helps or confused things even more.
Cheers
Mike
 
What is the ohms reading on the back of the speaker cabinate at the red and black inputs?

On my TLS 80's its about 9ohm , I would assume it should be near that .

Athanasios
 
Nashou66 said:
What is the ohms reading on the back of the speaker cabinate at the red and black inputs?

On my TLS 80's its about 9ohm , I would assume it should be near that .

Athanasios
Click to expand...
Yes same 9.1 9.2
I think when they removed the tone control switch there's no power going to the mid, tweet and super tweeter.
On the under side of the X.O I connected a wire to + wire of the main speaker input terminal I then touched the other end of the wire on to the tweeter connection and it worked, did the same with s tweeter and it worked.
Is that confusing?
Mike.
 
09mike69 said:
Yes same 9.1 9.2
I think when they removed the tone control switch there's no power going to the mid, tweet and super tweeter.
On the under side of the X.O I connected a wire to + wire of the main speaker input terminal I then touched the other end of the wire on to the tweeter connection and it worked, did the same with s tweeter and it worked.
Is that confusing?
Mike.
Click to expand...


Hm they may have not re wired it correctly . The rear input wires should go to the crossover and from there it should distribute the input signal to all sections of the crossover.

In these pictures which wires are coming from the back inputs?

index.php


Also in the above picture, where does that yellow wire almost out of frame go to?


index.php


Athanasios
 
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