UPDATE:

It's been one month today since the successful repair of my JL Audio Fathom f113 subwoofer. I have played music in the living room everyday and the subwoofer is working flawlessly. I have the Fathom set for Auto turn-on when a music signal is sensed at the inputs, exactly the way I used it for nine years before the capacitor failure. All is well and hopefully I will not have any other issues for years to come. Long live my JL Audio subwoofer.

:thumbsup:

Nice job Dan
What ESR meter did you purchase? I have an old Heathkit Cap tester that runs them under load and voltage selectable from 2-600v, great for checking coupling caps. Sometimes its difficult to test mylars. Curious if yours will test Mylar
Sometimes it almost mandatory to have a good cap to compare.

John.......I use the Signstek MESR-100 capacitor meter.

https://www.amazon.com/Signstek-MESR...70_&dpSrc=srch

Dan, thanks for all the details and pics! My F112 (v1) died about a week ago, leading me to search online. I found posts from others complaining about similar issues. However only your post had sufficient info for me to attempt this on my own.

I also had trouble removing the amp, but the M6 machine screws did the trick! I only needed one and the amp came out enough for me to do the rest.

Once the amp was on my workbench, I removed the hex bolts holding the PCB and the power transistors, but the PCB was still stuck. Turns out there is some black mushy material (silicon caulking?) on the large capacitors that hold it to the metal. Slicing it near the metal freed it.

I did not have an ESR device, so I ended up changing both caps that you referenced from Mouser. I double checked my work and put everything back together including the cable ties that hold the wires in place.

I plugged the amp back in and attached a few screws to hold it in place. I plugged in the power cable and it turned back on! My amp was finally on again! Big sigh of relief.

At this point, I heard some ground noise I never heard before. I don’t know why, but figured maybe something else had also gone wrong. Since the hum was mild, I figured it should be fine from in my listening chair. I unplugged power, finished securing all the screws, then moved the sub back into its place. I plugged in the source RCAs and the power cable. The ground hum was now gone... no idea about this one.

I played a few tracks and all was well!

Oddly, I became somewhat accustomed to listening without the sub, and realized I had its level higher than necessary. I adjusted it slightly down and now the bass transitions smoothly from my Olympica III’s to the sub bass of the F112.

Very happy this repair went so smoothly. Thanks again Dan!

Thanks Ivan for making this a sticky thread!

The F113 repairs Dan specified worked exactly the same for my F112.

I should also add that my first thought when the sub died was not how to repair it... but what to upgrade to! :lmao:

r0b.......You are quite welcome. I am happy to know my thread and the repair I outlined served to get you back up and running. I have to commend you on your effort. Digging into the back side of a JL Audio f112/f113 can be daunting. You saved yourself about $500.00 in repair and shipping cost, not to mention wrestling that monster of a sub back into its shipping box and getting it shipped. Congratulations on your successful repair. . :applause:

I wholeheartedly agree with Dan.....I too dread the day one of my JL subs need service, but chances are it won't be that big a deal to fix. So often, the culprit in broken audio gear is caps. Not always, but often!

In looking over this thread again, and Dan's photos, I can't help but be impressed with the amplifier module contained in the F113. It is impressive.

I have two E110's in my bedroom theater, and one E112 in my 2 channel office system. They do a fabulous job. :yes:

@dan,:cheers:
@pete, agreed!

The fact that this was a rather simple repair, and that it was only caps, gives me more confidence in JL Audio subs! I will continue to be a customer when it is time to upgrade or expand into 2.2. I would have thought the actual moving driver would fail first but fortunately it is still kicking.

FWIW, the date on the box for this sub is 2009. I got it used in 2014, and its use is regular / near daily at low to moderate volume. So like Dan, it has served me well for many years and I also leave its power setting on Auto.

Makes me wonder why only the power supply caps needed replacement. Is it because of the 85C specification?

Like others have noted, caps don’t last forever. I’d be willing to change out all of the caps now that I have seen how easy it is to change two.

r0b.......I don't have a schematic for my f113 but as I am able to determine the auto-on sensing circuit cuts power to the amplifier circuitry, yet the auto-on circuit remains energized 24/7 when the auto-on mode is selected in order for it to control the relays that power the amplifier once an incoming audio signal is detected. This means the capacitors in the amplifier are only energized while music is playing, and once the auto-on circuit senses loss of audio signal and times out the amplifier is no longer energized. This would naturally extend the life of the amplifier's capacitors.