Hi everyone,
I have been having issues with an Infinity Intermezzo 3.5c Centre Speaker. The mid is very very low, almost no sound.
I have traced it back to one of the capacitors.
The service manual shows C6 as 2.5uF 100V, however on the board itself it says 25uF 100V.
Since it's by a factor of 10, I'm hoping someone can look at the XO and can confirm if it should be 2.5uF or 25uF.
The original cap is blown and the jacket on the outside is damaged so I can't read what the actual value is on the old cap.
Any help would be appreciated.
TIA
I have been having issues with an Infinity Intermezzo 3.5c Centre Speaker. The mid is very very low, almost no sound.
I have traced it back to one of the capacitors.
The service manual shows C6 as 2.5uF 100V, however on the board itself it says 25uF 100V.
Since it's by a factor of 10, I'm hoping someone can look at the XO and can confirm if it should be 2.5uF or 25uF.
The original cap is blown and the jacket on the outside is damaged so I can't read what the actual value is on the old cap.
Any help would be appreciated.
TIA
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Absolutely no expert here (!) but, I would imagine it's 2.5uF simply for the reason it's paralleled with a C7 which is 0.1uF therefore making a 2.6uF cap
Often good to state the problem in an accessible manner!
I know nothing about this speakers' details, but I can follow a crossover. C6 is part of a midrange filter.
2.6uF is an unlikely value for such an application. C6 and C7 paralleled form a series bandpass filter in combination with L4. As do C8 and C9 paralleled with L5.
I would lift the C7 capacitor to see what the circuit board marking is. C6 at 25uF and C7 at 2.5uF would be a reasonable way to make something near a preferred value of 27uF.
I am surprised the 25uF 100V cap has blown, which suggests severe overdriving, or heat problems from other components due to poor ventilation. A 25uF capacitor in film is quite a large component, and size is often a good indicator of value. It is also easy to recognise MKP film capacitors in their plastic cases from non-polar electrolytics in metal cans which are much smaller for a given value. An NPE is much more likely to pop too, having a significant resistance which causes heating.
A more considered investigation would require a simulation and knowledge of the drivers.
I know nothing about this speakers' details, but I can follow a crossover. C6 is part of a midrange filter.
2.6uF is an unlikely value for such an application. C6 and C7 paralleled form a series bandpass filter in combination with L4. As do C8 and C9 paralleled with L5.
I would lift the C7 capacitor to see what the circuit board marking is. C6 at 25uF and C7 at 2.5uF would be a reasonable way to make something near a preferred value of 27uF.
I am surprised the 25uF 100V cap has blown, which suggests severe overdriving, or heat problems from other components due to poor ventilation. A 25uF capacitor in film is quite a large component, and size is often a good indicator of value. It is also easy to recognise MKP film capacitors in their plastic cases from non-polar electrolytics in metal cans which are much smaller for a given value. An NPE is much more likely to pop too, having a significant resistance which causes heating.
A more considered investigation would require a simulation and knowledge of the drivers.
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I think the 25uf cap (C6) is an electrolytic cap, the capacitor symbol has hatching between the plates, which usually indicates its an electrolytic capacitor.
It probably blew up after the midrange went open circuit, which would cause the cct to resonate, thereby causing that component to experience voltage it wasn't designed for.
I would also check capacitor C8 to see if it has suffered damage as well.
It probably blew up after the midrange went open circuit, which would cause the cct to resonate, thereby causing that component to experience voltage it wasn't designed for.
I would also check capacitor C8 to see if it has suffered damage as well.
So is the general consensus is that C6 should be 25uF, so the markings on the board is correct and the service manual is incorrect?
Yes, 25uF NPE 100V. I think afa wins some sort of coconut for psychic ability! It is a typo in the service manual.
But as afa said, it probably all went haywire when the midrange blew up or went open circuit. Of course, there may be other faults.
This mid could be trouble to replace! You must measure the resistance of the mid. Looks like you must take it out of circuit to do this.
Applying a 1.5V AA battery to the terminals is a good old trick. You should get a crackle if it is working.
But as afa said, it probably all went haywire when the midrange blew up or went open circuit. Of course, there may be other faults.
This mid could be trouble to replace! You must measure the resistance of the mid. Looks like you must take it out of circuit to do this.
Applying a 1.5V AA battery to the terminals is a good old trick. You should get a crackle if it is working.
My Prelude MTS center midrange is completely locked up and replacement are impossible to find. What is the recommended Dayton replacement you mentioned?
The Dayton replacements are the ND90-8 (8 ohm version) or ND90-4 (4 ohm version). I can't recall which one I used.
Keep in mind this is not a drop in replacement. You have to do a lot of hacking and surgery to the cabinet to get it to fit, and once it fits, it will make noise, but in no way a replacement for the original. See link below.
In the end I had to send my mids to Belgium as that is the only place I felt it could be done property. It ended up costing some stupid money due to the 20%+ taxes and duties on everything and shipping, but they sound like new.
https://www.avsforum.com/threads/infinity-prelude-mts.1519202/
Keep in mind this is not a drop in replacement. You have to do a lot of hacking and surgery to the cabinet to get it to fit, and once it fits, it will make noise, but in no way a replacement for the original. See link below.
In the end I had to send my mids to Belgium as that is the only place I felt it could be done property. It ended up costing some stupid money due to the 20%+ taxes and duties on everything and shipping, but they sound like new.
https://www.avsforum.com/threads/infinity-prelude-mts.1519202/