R-110SW / R-112SW / R-115SW Repair Blog

[Rossi32s]

1 minute ago, Heder silva said:

So in my board witch ones I replace? Can you mark on my picture please?

 

[Heder silva]

Thanks very much. And it will fix the problem of shutting down when I put volume in the receiver more than 60%? Thanks.

[Heder silva]

This one is the big white one?

[Rossi32s]

2 minutes ago, Heder silva said:

This one is the big white one?

No.. there is one inside the silicone glue

[Heder silva]

Ok. Thanks. And it will fix problem or I have to replace more parts?

[Rossi32s]

1 minute ago, Heder silva said:

Ok. Thanks. And it will fix problem or I have to replace more parts?

Should fix it

[Heder silva]

Ok. Thanks. One more question. Do you know the reference of the parts? Because if I take of glue and I cont see it write on the components? If you can it’s possible to reel me the reference? Thanks very much.

[Diesel94]

Hello, I have a KSW-100 subwoofer that stopped working. I inspected the amplifier board and discovered two transistors that had gotten hot enough to scorch the circuit board and apparently cause a nearby electrolytic capacitor to overheat and vent. It looked like a simple case of replace the transistors and capacitor. I started the apparently simple repair before seeing this thread, or doing any other research, after all... what could go wrong? I desoldered the transistors without too much problem and then the capacitor, which came out with a little tube-shaped thing over each leg. I have a favorite expression: "experience is what you get seconds after you needed it". After a little research, I discovered what a "via" is. 

 

I figured I'd need to jumper at least one leg of the capacitor now. In the case of C5 (the capacitor actually removed) the positive lead connects to a trace on the bottom of the board leading to the 2nd pin of a transistor and other places and there are no obvious traces to the positive lead on the top side of the board. My problem is, I can't figure out what the negative pin is supposed to connect to. I have used the continuity setting on a multi-meter to look for continuity from C5's negative lead hole to every pin and pad on the top and bottom of the board and cannot find a path. I have done the same thing from the positive pin of C5's counterpart, C6 and can find no connection. I have inspected the board using a magnifying hood and very bright light and can't find any trace leading to C5's negative through hole. I even created a schematic of the board to possibly help figure out this mystery. 

 

I've attached photos of the top and bottom of the board with the appropriate connections circled. I've also attached my attempt at a schematic of the board (based very loosely on the board layout). I'm not that worried about saving the amp, as much as I'm baffled by why I can't find all the connection points for C5 and C6. I'm not any kind of electronics hobbyist, but I did get my brother (a retired electrical engineer from the aerospace industry) helping me, and this little amplifier board is making both of our heads hurt. What are we missing?

 

Any ideas?   

[Rossi32s]

3 hours ago, Diesel94 said:

Hello, I have a KSW-100 subwoofer that stopped working. I inspected the amplifier board and discovered two transistors that had gotten hot enough to scorch the circuit board and apparently cause a nearby electrolytic capacitor to overheat and vent. It looked like a simple case of replace the transistors and capacitor. I started the apparently simple repair before seeing this thread, or doing any other research, after all... what could go wrong? I desoldered the transistors without too much problem and then the capacitor, which came out with a little tube-shaped thing over each leg. I have a favorite expression: "experience is what you get seconds after you needed it". After a little research, I discovered what a "via" is. 

 

I figured I'd need to jumper at least one leg of the capacitor now. In the case of C5 (the capacitor actually removed) the positive lead connects to a trace on the bottom of the board leading to the 2nd pin of a transistor and other places and there are no obvious traces to the positive lead on the top side of the board. My problem is, I can't figure out what the negative pin is supposed to connect to. I have used the continuity setting on a multi-meter to look for continuity from C5's negative lead hole to every pin and pad on the top and bottom of the board and cannot find a path. I have done the same thing from the positive pin of C5's counterpart, C6 and can find no connection. I have inspected the board using a magnifying hood and very bright light and can't find any trace leading to C5's negative through hole. I even created a schematic of the board to possibly help figure out this mystery. 

 

I've attached photos of the top and bottom of the board with the appropriate connections circled. I've also attached my attempt at a schematic of the board (based very loosely on the board layout). I'm not that worried about saving the amp, as much as I'm baffled by why I can't find all the connection points for C5 and C6. I'm not any kind of electronics hobbyist, but I did get my brother (a retired electrical engineer from the aerospace industry) helping me, and this little amplifier board is making both of our heads hurt. What are we missing?

 

Any ideas?   

You're not in the correct thread for the model You're asking about. 

 

That said.   C5 only connects to the circuit on that negative lead on the bottom side of the board.  Can't see where the other one goes since you have a capacitor in the hole.

[Diesel94]

Sorry for posting in the wrong place. I'm new to this site and relatively inexperienced with posting on forums in general. Should I be posting this as a new topic in the Technical/Restorations forum? Please advise.

 

As for the trace being covered by C5, you'll note in the picture that C5 has been removed. I assumed that vias were used on the capacitors as they can only be soldered from the bottom of the board because the body of the capacitor covers the through-hole. Since one leg connects to traces on the bottom of the board, it only makes sense that a via was used on the other leg because it had to connect to a top-side trace.  I have studied the top of the board using a magnification hood and bright light source (bright enough to illuminate through the board) and can see no trace. More importantly, I believe this is a two-sided board (as opposed to 3 or more layers). All components are "through hole" types and therefore all components have leads sticking out of the bottom of the board, including those that have connections only to the top of the board (there are no surface-mount components on either side of the board). Since I stupidly removed the vias along with C5, I assumed I probably compromised the connection point on the board. So, I checked C5's compliment, C6 (which was not removed or tampered with), using C6's positive lead (as it connects to a PNP transistor as opposed to the NPN transistor C5 connects to) I can find no other trace, component, or lead attachment point, on the top or bottom of the board that shows a connection to the positive leg of C6. It's like the positive leg of C6 and the negative leg of C5 simply aren't connected to anything, which makes no sense. All of the 38 remaining components are fully connected to other components or traces on the board.

 

Anyway, I would appreciate your advice as to where I should post this topic.

 

Thanks!

[Diyflyer]

On 12/29/2024 at 2:53 PM, Rossi32s said:

No.. there is one inside the silicone glue

Hello Rossi32s, Thank you for your prior guidance on the original board. I also have a SPL-150 replacement Amp that Klipsch sent, which also went bad, that has the white ceramic resistor on an extended board. Please see pictures and advice which ones to capacitors replace. Do I also replace the ceramic resistor ?

[will111]

Hello, I have one of those 110SW sub amps as well. I already did the diagnostics and tried repairing it some time ago, turned out to be pretty much waste of time as the fault is propably in IRS chip itself and replacing that is pointless from labour point of view. And quite frankly too difficult to do with my equipment. So I just bought another complete power amp section. Thing is that I would still like to use the processed input signal from the original amp board. It goes through the volume control and propably some kind of fixed filter also, plus there's the adjustable crossover. I believe the preamp section should be fine, but can anybody help and tell me where would be the correct point to "take out" the signal for the new power amp? Directly from pin3 of the IRS2092 chip? Some other place? Has someone done it? As it is all built as one pcb, its kind of difficult to make out, where exactly does the socalled preamp section end and power amp section start.

 

The replacement amp by the way is exactly the same thing, as is it uses IRS2092 too, it has a signal in connector, I just need the signal and would like to retain the ability to control gain and filter frequency. New amp board will be attached to the original plate.

[Diyflyer]

On 1/7/2025 at 2:25 PM, Diyflyer said:

Hello Rossi32s, Thank you for your prior guidance on the original board. I also have a SPL-150 replacement Amp that Klipsch sent, which also went bad, that has the white ceramic resistor on an extended board. Please see pictures and advice which ones to capacitors replace. Do I also replace the ceramic resistor ?

@Rossi32s Can you please comment on this.

[Rossi32s]

On 1/7/2025 at 3:25 PM, Diyflyer said:

Hello Rossi32s, Thank you for your prior guidance on the original board. I also have a SPL-150 replacement Amp that Klipsch sent, which also went bad, that has the white ceramic resistor on an extended board. Please see pictures and advice which ones to capacitors replace. Do I also replace the ceramic resistor ?

The resistor is fine; replace the same four capacitors.  

Edited Thursday at 08:21 PM by Rossi32s

[Rossi32s]

15 hours ago, will111 said:

Hello, I have one of those 110SW sub amps as well. I already did the diagnostics and tried repairing it some time ago, turned out to be pretty much waste of time as the fault is propably in IRS chip itself and replacing that is pointless from labour point of view. And quite frankly too difficult to do with my equipment. So I just bought another complete power amp section. Thing is that I would still like to use the processed input signal from the original amp board. It goes through the volume control and propably some kind of fixed filter also, plus there's the adjustable crossover. I believe the preamp section should be fine, but can anybody help and tell me where would be the correct point to "take out" the signal for the new power amp? Directly from pin3 of the IRS2092 chip? Some other place? Has someone done it? As it is all built as one pcb, its kind of difficult to make out, where exactly does the socalled preamp section end and power amp section start.

 

The replacement amp by the way is exactly the same thing, as is it uses IRS2092 too, it has a signal in connector, I just need the signal and would like to retain the ability to control gain and filter frequency. New amp board will be attached to the original plate.

Doubtful that you have a bad IRS IC.  

[will111]

Well, maybe not. Honestly I dont exactly remember, I did some measurements with a scope, but it was already a few months ago from now. The result was that I decided to just order a new amp section (its not original and didnt include any power source, so the price was very reasonable).

Before any of that I also tried replacing basically all of the possible "basic" components (caps, resistor). I read this topic and other sources for all kinds of possible faults. All this didnt help one bit. The fact is that its a total pain in the *** pcb to work with. I've repaired about 10+ different amps before so not a total novice...but nothing has ever been so difficult (to access, work on) before.

 

Even if its not the IRS IC, I think the power amp is beyond reasonable repair. Might be some other small components on the board, under all that goo and glue crap, but I'm not looking forward to ripping the whole pcb off the backplate. Its glued on there real hard, and besides it has to be airtight at the end.

 

Do you have some reason to believe that the issue is before the IRS chip? The fault with the amp was that it was making some quite random thumping pulses when powered on, and if I remember correctly did not play any sound from the input.

[Rossi32s]

1 minute ago, will111 said:

Well, maybe not. Honestly I dont exactly remember, I did some measurements with a scope, but it was already a few months ago from now. The result was that I decided to just order a new amp section (its not original and didnt include any power source, so the price was very reasonable).

Before any of that I also tried replacing basically all of the possible "basic" components (caps, resistor). I read this topic and other sources for all kinds of possible faults. All this didnt help one bit. The fact is that its a total pain in the *** pcb to work with. I've repaired about 10+ different amps before so not a total novice...but nothing has ever been so difficult (to access, work on) before.

 

Even if its not the IRS IC, I think the power amp is beyond reasonable repair. Might be some other small components on the board, under all that goo and glue crap, but I'm not looking forward to ripping the whole pcb off the backplate. Its glued on there real hard, and besides it has to be airtight at the end.

 

Do you have some reason to believe that the issue is before the IRS chip? The fault with the amp was that it was making some quite random thumping pulses when powered on, and if I remember correctly did not play any sound from the input.

Thumping is 100% caused by the 22UF 50v cap directly between the IRS IC and the Output MOSFETS.  If you are hearing that thump,  the IRS IC is fine.  At this point in time, the amount of time the, 'now brown' glue on these amps is turning very acidic when it gets warm. It etchs the copper, and many resistors, transistors, and diodes fall off the boards when the glue is removed.  it's a 50/50 shot at repairing those early versions now.  We probably have a box of 30 at this point,  we threw out just as many back in October.

 

[will111]

I dont know how exactly you can be so 100% sure about it...but maybe you are right.  Fact is though that it 1) looks absolutely fine 2) measured fine with ESR being ok too. In all instances when a cap has been the issue or cause of actual problems on some amp board before, it was actually showing me totally out of whack numbers when measured. Not the case here, so I dont know...why would it be the cause? Anyway, even though i am somehow able to measure this cap...it is all but impossible to remove/replace it without tearing the whole thing apart...and propably even ruining the pcb underneath all the goo while trying. I would have have just cut it off somehow and tried to replace it somehow with a new one on the other side of the board, but strangely it seems that this particular cap is not even on the pcb with through holes :S

 

So yeah, just not worth all the work and effort really. But if you think the IRS is fine and the cap it is the problem, then the preamp section should be fine and working too. Can you suggest or have any kind of opinion about trying to "steal" the analog input signal from somewhere on the board before it goes into the IRS? What would be the point on the pcb to do that? Straight on pin 3 and 2 of IRS not a good idea?

[Rossi32s]

16 minutes ago, will111 said:

I dont know how exactly you can be so 100% sure about it...but maybe you are right.  Fact is though that it 1) looks absolutely fine 2) measured fine with ESR being ok too. In all instances when a cap has been the issue or cause of actual problems on some amp board before, it was actually showing me totally out of whack numbers when measured. Not the case here, so I dont know...why would it be the cause? Anyway, even though i am somehow able to measure this cap...it is all but impossible to remove/replace it without tearing the whole thing apart...and propably even ruining the pcb underneath all the goo while trying. I would have have just cut it off somehow and tried to replace it somehow with a new one on the other side of the board, but strangely it seems that this particular cap is not even on the pcb with through holes :S

 

So yeah, just not worth all the work and effort really. But if you think the IRS is fine and the cap it is the problem, then the preamp section should be fine and working too. Can you suggest or have any kind of opinion about trying to "steal" the analog input signal from somewhere on the board before it goes into the IRS? What would be the point on the pcb to do that? Straight on pin 3 and 2 of IRS not a good idea?

I'm saying 100% because out of a few hundred that we have done,  it has been the culprit every time.  Not sure you can ESR that cap since it's used as a decoupling capacitor in this circuit.  We use a huntron and know what to expect visually on the screen.

 

You can have thumping and still have other issues going on.  

[will111]

Yeah, i'll admit the measurements could have been not 100% reliable since i measured it in circuit.

 

Anyway, I tried to compare the signal on pin3 or IRS vs. the input signal (sinus from signal generator). It kind of resembles the signal given to rca input, but its wayy distorted and seems to have a lot of some random noise, at least thats what the scope showed. Also, interestingly the gain control knob doesnt seem to have any effect there. Signal stays the same regardless of its position. Doesnt look like an option to take the input signal from anywhere on the original pcb.

Its seems like its easier to just hook up the new amp module with the power supply leads and take the input signal directly from the rca terminal. there's enough room to leave all the old crap on the backplate.

 

From your comments it seems that those amps basically break down without fail, pretty much all of them that were ever produced?

Edited Monday at 09:05 AM by will111