Bose Lifestyle 48 Acoustimass PS Issue

[ghiotom]

I've had this system for 20 years with no problems. One day, all audio is missing and it turns out the ps mosfets are blown along with associated components including controller IC. Found a guy on YouTube with similar problem and replaced the parts he mentioned as well as 1 additional mosfet in the feedback circuit. The system worked great for 3 months, now back to original problem with blown mosfets, etc. There are 2 10uF 25V caps on secondary with ESR of 8.6-8.8 ohms, my replacement cap measures 1.2 ohms. Does the ESR on the secondary caps seem high enough to take out the mosfets or should I be looking elsewhere? Remember the repair lasted 3 months, it didn't blow right away.

[b seshu]

Re: Bose Lifestyle 48 Acoustimass PS Issue

Z8v x16

[sam_sam_sam]

Re: Bose Lifestyle 48 Acoustimass PS Issue

There are 2 10uF 25V caps on secondary with ESR of 8.6-8.8 ohms, my replacement cap measures 1.2 ohms. Does the ESR on the secondary caps seem high enough to take out the mosfets or should I be looking elsewhere? Remember the repair lasted 3 months, it didn't blow right away.

Yes this is extremely high as you have found out if you compare it to a new one

I would highly recommend that you check all capacitors that are less than 100uf at a minimum or just checking all of them highly recommend