Hi this is my first post on these forums, although I have been lurking around here for quite a while. Lot of interesting stuff here for someone who is new to the field of tinkering.
I have a pair of Mission 701's that I bought second hand w/ the intention of fixing them up myself. Unfortunately they seem to have been messed up more than I initially thought (see pics). Capacitors, resistors and coils seems to have been fried up quite nicely, and need replacing. As it is, crossovers are not working and are even of two different designs (one circuit board says Mission 700, the other one 701).
So, sorry I don't have any impressive DIY project to show off (that might come once I get the speakers working again) but instead have a few boring questions:
1) The plastic "holders" the coils are wrapped around are melted and deformed , will the coils still serve their purpose or do I have to do a rewind?? And how do I do this if that is the case ?
2) The resistors are marked 1.5 ohm/5W but I havent found any exact replacement online - will a 1.5 ohm/10 W work just as well ?? (sorry I'm a bit rusty in my electronics knowledge)
3) What kind of caps should I buy as replacements? The ones that are dead are 5uF 50v (Tesla TF202) and I cant seem to find this exact combo online
Any help would be appreciated. Maybe even an online supplier recommendation?
Cheers,
Jan
I have a pair of Mission 701's that I bought second hand w/ the intention of fixing them up myself. Unfortunately they seem to have been messed up more than I initially thought (see pics). Capacitors, resistors and coils seems to have been fried up quite nicely, and need replacing. As it is, crossovers are not working and are even of two different designs (one circuit board says Mission 700, the other one 701).
So, sorry I don't have any impressive DIY project to show off (that might come once I get the speakers working again) but instead have a few boring questions:
1) The plastic "holders" the coils are wrapped around are melted and deformed , will the coils still serve their purpose or do I have to do a rewind?? And how do I do this if that is the case ?
2) The resistors are marked 1.5 ohm/5W but I havent found any exact replacement online - will a 1.5 ohm/10 W work just as well ?? (sorry I'm a bit rusty in my electronics knowledge)
3) What kind of caps should I buy as replacements? The ones that are dead are 5uF 50v (Tesla TF202) and I cant seem to find this exact combo online
Any help would be appreciated. Maybe even an online supplier recommendation?
Cheers,
Jan
Attachments
To answer the parts question.
Yes a 10 watt part is fine to replace a 5 watt.
The 5uf cap is a bi-polar or non polarised electroylitic. 4.7uf should be OK. You can also fit two 10uf 63 volt "ordinary electrolytics" connecting them in series with either plus to plus or minus to minus (doesn't matter)
If the coil wire has had the insulation burned then they could have "shorted turns" and so would need new wire. Otherwise they should still be OK.
Yes a 10 watt part is fine to replace a 5 watt.
The 5uf cap is a bi-polar or non polarised electroylitic. 4.7uf should be OK. You can also fit two 10uf 63 volt "ordinary electrolytics" connecting them in series with either plus to plus or minus to minus (doesn't matter)
If the coil wire has had the insulation burned then they could have "shorted turns" and so would need new wire. Otherwise they should still be OK.
Hehe....just thinking the same thing. I think the coils might have melted due to the heat from the resistor catching fire(!)
Yep, as far as I know tweeters are still ok (I have tested them briefly), the previous owner swapped the woofers with an unknown brand (prob because they were abused....), so they are no longer the original white/black ones but work. Does that btw mean I have to change the crossover design in any way?
I am not expecting grand hifi sound, just want to fix them up for my daughter to use w her iPod etc.
Yep, as far as I know tweeters are still ok (I have tested them briefly), the previous owner swapped the woofers with an unknown brand (prob because they were abused....), so they are no longer the original white/black ones but work. Does that btw mean I have to change the crossover design in any way?
I am not expecting grand hifi sound, just want to fix them up for my daughter to use w her iPod etc.
Thanks for the answers, really helpful.
One more question re. the capacitors - is the voltage rating a maximum rating, i.e. a 100V will be just fine if I cant get hold of a 50 V?
For instance this ?
And how do I go about finding a replacement coil in case it's toast?
Anything I can measure ? Wire thickness and diameter/length ?
One more question re. the capacitors - is the voltage rating a maximum rating, i.e. a 100V will be just fine if I cant get hold of a 50 V?
For instance this ?
And how do I go about finding a replacement coil in case it's toast?
Anything I can measure ? Wire thickness and diameter/length ?
Yes, thats a maximum voltage rating. So a 100 or 200 or 600 volt cap would be fine to replace a 50 volt one.
Coils are hard work. Are they air spaced ? (no magnetic metal core). Guess measuring and counting turns and noting the diameter of the former is the only way if the coil is "shorted" and unmeasurable. My guess would be that they are probably OK... it takes a lot to fry the varnished insulation of copper wire.
Coils are hard work. Are they air spaced ? (no magnetic metal core). Guess measuring and counting turns and noting the diameter of the former is the only way if the coil is "shorted" and unmeasurable. My guess would be that they are probably OK... it takes a lot to fry the varnished insulation of copper wire.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.