C7 capacitor blew in my LC. What does it affect?

geokov

New Tinkerer
Nov 2, 2023
19
3
3
Hello all, I am new to this forum and also to vintage Mac ownership. I purchased a "re-capped" LC for a song but upon opening it I discovered that capacitor C7 had already blown up (it was soldered in upside down). I had a look at the schematics for the LC and I think I have narrowed it down to something to do with the sound but everything with the sound is still functioning as it should. The only thing I haven't been able to check is the microphone jack.

If someone with more experience could let me know the purpose of the C7 capacitor I would be very grateful.

It looks like I may have to re-cap the re-cap. Should I purchase tantalum capacitors or electrolytic capacitors? There seems to be some debate on the subject.

Cheers from Canada 🇨🇦:)
 

Attachments

  • LC damage.png
    LC damage.png
    1.9 MB · Views: 73
  • LC schematic.jpg
    LC schematic.jpg
    155.8 KB · Views: 70

Nixontheknight

Tinkerer
Nov 3, 2021
124
19
18
Hello all, I am new to this forum and also to vintage Mac ownership. I purchased a "re-capped" LC for a song but upon opening it I discovered that capacitor C7 had already blown up (it was soldered in upside down). I had a look at the schematics for the LC and I think I have narrowed it down to something to do with the sound but everything with the sound is still functioning as it should. The only thing I haven't been able to check is the microphone jack.

If someone with more experience could let me know the purpose of the C7 capacitor I would be very grateful.

It looks like I may have to re-cap the re-cap. Should I purchase tantalum capacitors or electrolytic capacitors? There seems to be some debate on the subject.

Cheers from Canada 🇨🇦:)
Tantalum capacitors are good for longevity, the Quadra 700 used them for all its capacitors, and lots of them are still going strong today. I may be biased because that's what my LC III was recapped with, but as I said, longevity and in some cases they may never need to be replaced again unless you're astronomically unlucky