Sunfire True Subwoofer MKIV

[Hasratt Mohamed 2]

I would like to obtain the electrical circuit specs for the above MKIV subwoofer as mine is blowing all external fuses and will not work now. I want to save it so I am trying to help my technician who gas to replace many parts but is not sure of their printed numbers

[Half Life 1,113]

Welcome to theCarverSite!

 

We have the Owners Manual in our Library.  You can find it  in the Manuals and Specsheets section above.  Once that page is open you'll see a spreadsheet with tabs along the bottom for the various Bob Carver gear.  Select the Sunfire tab and scroll to near the bottom and you'll find the Owners Manual.  Unfortunately, most Sunfire schematics are not found in the wild.  Your unit should have a 6.25 Slo-Blo fuse in it.  If it's blowing instantly when turning on, it could be bad output transistors, bad capacitors, bad rectifiers.  There are some You-tube vides that describe the problem you're having, if you're comfortable testing and fixing it yourself.  If not, you may wish to have it repaired by Greg at Nelion.  He knows Bob Carver gear inside and out and does great work.  Good luck!

[3M_Audio 2,278]

Welcome! As @Half Life pointed out, schematics for Sunfire gear aren't readily available, so good luck with a search. The sub is definitely worth saving.

[Charlie 18,319]

[Sk1Bum 12,794]

Hello Hasratt and welcome to thecarversite.com. Glad you found us.

 

As others mentioned, Sunfire schematics are rare. If you happen to find the one you're looking for, we'd sure appreciate adding a copy to our library.

 

We do have the True Sub EQ, Super Junior, and the Carver amp used in the NHT Sub 2 schematics. I have no idea if those would be helpful to you or not.

 

Good luck with your search.

 

 

[Hasratt Mohamed 2]

They would not be helpful to solve my problems on a Sunfire MKIV subwoofer 

[AndrewJohn 10,820]

On 2/28/2026 at 11:54 AM, Hasratt Mohamed said:

They would not be helpful to solve my problems on a Sunfire MKIV subwoofer 

 

Actually, the main module design would give a good tech huge head start on how yours is designed, and where to look for the failures.  These subs are all due for service at this age.  There is one expert in IL that repairs them all the time - not sure where you are located, but if in the US, I would send it to that guy who knows his way around the Sunfire subs very well, and won't be "learning" asking for specs.  They are complex.

[BobTFM35 3,045]

@Hasratt Mohamed I echo the recommendation of @AndrewJohn in sending it to someone more versed in their design. I can possibly think of two more repair places that are well versed in this design.

 

But if you want to continue the path you started maybe the following might be of interest.

 

If you are a member of the forum that I'm listing below, there was a post on "Sunfire True Subwoofer MK IV repair". Within the post is a download in post #11 for a Cap listing. This may or may not help but it may be a start as he lists the position number on the board to help in verification of possible values. Since the listing is from the person starting the subject, I'm assuming that this is for the MKIV.

 

Sunfire True Subwoofer MK IV repair | Audiokarma Home Audio Stereo Discussion Forums

 

 

Hope this helps.

[AndrewJohn 10,820]

5 minutes ago, BobTFM35 said:

@Hasratt Mohamed I echo the recommendation of @AndrewJohn in sending it to someone more versed in their design. I can possibly think of two more repair places that are well versed in this design.

 

But if you want to continue the path you started maybe the following might be of interest.

 

If you are a member of the forum that I'm listing below, there was a post on "Sunfire True Subwoofer MK IV repair". Within the post is a download in post #11 for a Cap listing. This may or may not help but it may be a start as he lists the position number on the board to help in verification of possible values. Since the listing is from the person starting the subject, I'm assuming that this is for the MKIV.

 

Sunfire True Subwoofer MK IV repair | Audiokarma Home Audio Stereo Discussion Forums

 

 

Hope this helps.

 

Excellent, @BobTFM35.  thanks for digging that up from the AK forum.

 

The only thing I would add is that of the 5 Sunfire subs I have had, the failure is not only the Capacitors, but something else that has failed, causing other components in other modules.  Could be a transistor blowing, or resistor burning..., it takes real diagnosis from a good tech that can do it, without having a roadmap... just my opinion, of course.  (And, from experience, on 3 of the 5 I have owned, I recapped them, thinking - no, hoping - that would fix them.  It didn't. I had to get a real tech to do the real diagnosis to fix them.)

[Hasratt Mohamed 2]

3 hours ago, AndrewJohn said:

 

Actually, the main module design would give a good tech huge head start on how yours is designed, and where to look for the failures.  These subs are all due for service at this age.  There is one expert in IL that repairs them all the time - not sure where you are located, but if in the US, I would send it to that guy who knows his way around the Sunfire subs very well, and won't be "learning" asking for specs.  They are complex.