Hi all. I'm new to this group, but it seems full of very knowledgeable people and I wonder if you'd be able to help me out? I have a pair of mission 770 freedom Mark V which I really do love. I keep on comparing them against other speakers and they keep on coming out better however looking at the crossover I see that one of the resistors has got so hot that it's melted the plastic that has attached to so I think there must be some serious need for replacing some of the components such as the resistors and capacitors. Of course these are 40 yrs old and I'm a rank amateur in recognising and decoding the codes on the components so that I can replace them. Anyone to hold my hand through this would be much appreciated. Note I have looked at other posts and there is nothing that answers my questions. . Many thanks
Welcome to the forum!
Post photos in the 'Loudspeakers', 'Multi-Way' section of the forum and help will wing your way!
Post photos in the 'Loudspeakers', 'Multi-Way' section of the forum and help will wing your way!
To take with you, the following components have been identified as being in the crossover of the Mission Freedom V loudspeaker:
Resistors: 2 x 4.7 ohm and 1 x 3.3 ohm (wirewound types)
Capacitors: 2 x 15 uF (bipolar electrolytic type) and 1 x 4.7 uf (film type)
Inductors: 2, but each of unknown mH value.
Check out your crossover against the above information before making your post in 'Multi-Way'.
P.S. I haven't yet come across a crossover schematic for this particular speaker version.
Resistors: 2 x 4.7 ohm and 1 x 3.3 ohm (wirewound types)
Capacitors: 2 x 15 uF (bipolar electrolytic type) and 1 x 4.7 uf (film type)
Inductors: 2, but each of unknown mH value.
Check out your crossover against the above information before making your post in 'Multi-Way'.
P.S. I haven't yet come across a crossover schematic for this particular speaker version.
Thanks so much for your reply. I will post there.
BTW do you know if the resisitors should be replaced? One had melted the plastic casing. That can't be right!.
Interstingly it has only one bipolar cap.
BTW do you know if the resisitors should be replaced? One had melted the plastic casing. That can't be right!.
Interstingly it has only one bipolar cap.
I believe there is a history of such overheating with regards to this particular model of loudspeaker.
Either the resistors were underrated in wattage terms or the owners simply played the speakers continuously at high volume.
By that, do you mean the 4.7 uF film cap, which can only be bipolar (non-polar)?
There are instances where two polarised electrolytics are connected back to back to simulate a single bipolar electrolytic of half the capacitance.
Or do you mean there are not 2 x 15 uF bipolar electrolytics?
Either the resistors were underrated in wattage terms or the owners simply played the speakers continuously at high volume.
By that, do you mean the 4.7 uF film cap, which can only be bipolar (non-polar)?
There are instances where two polarised electrolytics are connected back to back to simulate a single bipolar electrolytic of half the capacitance.
Or do you mean there are not 2 x 15 uF bipolar electrolytics?
Thanks.
i meant the blue cap visible in the photo. But you are right - there are two of them - in parallel - the other was hiding underneath.
I cant read the values without removing it which I will do.
Do you think there is value in replacing these ?
Would you advise replacing the resistors or live with running hot?
i meant the blue cap visible in the photo. But you are right - there are two of them - in parallel - the other was hiding underneath.
I cant read the values without removing it which I will do.
Do you think there is value in replacing these ?
Would you advise replacing the resistors or live with running hot?
OK Close this thread and transfer the information to your new thread: https://www.diyaudio.com/community/...er-upgrade-advice-please.421150/#post-7871077