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

[exscape]

Hello everyone!

I just purchased a broken R-112SW, assuming the fault would be the overheated component near that one resistor, but it turns out that while that MAY also be the case, that wasn't the only fault present.

 

Skip until the next heading if you don't want the details of what I've found so far, but rather my questions!

 

Someone else has been in here and replaced stuff prior to me, and apparently they didn't succeed. "That" resistor is a 5 W 820 ohm white one, way up in the air on long legs, so presumably they were aware of the heat issue and tried to work around it. A few others components are also mounted on very long legs though I seriously doubt it helps for those (one of them being a diode, possibly a Zener).

 

Anyway, the bigger problem is that I only have one output transistor, and I assume two are supposed to be there. I haven't found ANY pictures of them though, so I'd be very thankful if someone with a R-11x amp could check theirs! The one that IS there doesn't have the white weave(?) present on other images I've seen (all with the transistor "cover" on, hiding the information I seek).

 

The back of the board is also damaged around the transistors, either when they blew or when someone tried to repair it.

 

There's a short between the + and - rails on the amp board (the PSU works, unless connected to the amp). I haven't diagnosed this one yet; there are some suspect traces that seem to run very close to one MOSFET pin where there's some PCB damage, but it could also be e.g. the cap across the rails.

EDIT: I solved this one, the short is visible in my picture (PCB back), bottom left, some kind of copper wire strands (or solder wick strands) were shorting them.

There's still a short between one supply rail and the output though.

 

The 22 uH inductor on the output also appears blown, there's a crack in the casing. I can only check the DC resistance though and it reads as 0.05 ohms (after nulling out the probe resistance), and I have no idea what to expect for an inductor in powerful class D amp.

EDIT: I just noticed this crack exists on your pictures too, and a DC resistance of 30-50 mOhm is pretty expected, so there's not really any evidence it's blown.

 

My questions a bit more succinctly:

 

1) Could someone post pictures of the output MOSFETs (and the component(s) in between them if any) and their exact part numbers? I have a badly soldered IRFB4227 there on the right, and nothing but a scarred PCB on the left. I've no idea if the other is supposed to be P-type or N-type as this is my first class D amp; I've found designs with 2x N-type and designs with complementary pairs.
I don't even know if the 4227 is correct since it's clearly been tampered with.

 

2) Pictures of the back of the PCB around the MOSFETs would also be truly excellent. I don't know exactly where the left MOSFET is supposed to be connected, nor do I know what part of that mess (see my photos!) is correct and what isn't.

 

3) Any ideas on what kind of ripple is OK on the PSU? I haven't checked with my scope yet, but my multimeter suggests 4 V AC is present on the 57-ish volt rails! And the frequency reads as about 400 Hz? I don't trust that fully though and will check more carefully unless this is to be expected.

Edit: I checked on the scope and there's no worries. The noise is about 170 mV peak to peak at ~550 kHz.

 

4) Any other general advice?

 

Thanks in advance

Edited December 3, 2022 by exscape
Updates

[exscape]

I ordered a couple of IRFB4227 MOSFETs after checking out the reference design (IRAUDAMP7S) and datasheet of the class D amp (IRS2092S) and learning it's designed to use two n-type MOSFETs...

 

... but I wonder if I have more PCB damage. A few things aren't connected as I expect from the reference design/datasheet. I expect there will be variations, but still.

 

One connection isn't as I expect from the high-side MOSFET (the right one). Could someone check this one on a working amp (or at least one that hasn't had damage to this part of the circuit)?

I think there should be a direct connection between source (pin 3) to the VS pin of the driver, which is pin 13, the 4th pin on the right side, counting upwards away from the plate, but I measure 35k and increasing (charging some capacitor).

Judging the schematic in the reference design, this pin is used by the gate driver as part of the current loop to the gate pin, so I don't think it can work properly with a 35k+ resistance in there.

The equivalent connection for the other MOSFET (VCC- to pin 10, 2nd pin from the bottom on the right side) is 0.07 ohms.

 

EDIT: I typed the wrong MOSFET pin initially (drain instead of source). Fixed now.

 

Another edit: I figured out good connections point to bodge this so it shouldn't be a big issue.

I do however believe my driver chip is dead after trying to measure the gate drive signal. I suppose it's possible it doesn't run without the MOSFETs but it shouldn't really know, right?

Edited December 5, 2022 by exscape
Typo fix #2

[kdammen]

@exscape I measured pin 13 of the IRS2092S chip to pin 3 of mosfet and I am getting 0.1 ohms. 

 

I am working on getting another one of these going. This one is showing no power after replacing the resistor, transistor, and 3 caps surrounding. I'm thinking I have either some bad diodes, resistors, or PWM. I plan to full recap and test more. I'm attaching a couple board images in case anyone needs more detailed views of this board. 

 

 

[kdammen]

Here are two more. 

[Davidr9889]

Hello. I just purchased 2 r112sw's from a friend of mine. I get them home and my arm slipped and broke the power switch. Is there any way I can jump the switch? I always unplug my subs after they automatically shut off anyway so when one shuts off ill  unplug the other

 

[kdammen]

20 hours ago, Davidr9889 said:

Hello. I just purchased 2 r112sw's from a friend of mine. I get them home and my arm slipped and broke the power switch. Is there any way I can jump the switch? I always unplug my subs after they automatically shut off anyway so when one shuts off ill  unplug the other

 

Check out page 2 of this thread. Someone else had the same question. 

 

[Davidr9889]

3 hours ago, kdammen said:

Check out page 2 of this thread. Someone else had the same question. 

 

Thank you. I must have over looked the post.

[Sinisa]

Hi.
My 115 SW started to shut down after a few minutes of use. I found many useful advices in this blog and decided to open it and try to fix it.  R39 was all brown and the outer layer was flaking. 330uF /16V C18 was bulging and its rubber seal at the bottom was pushed out. Following the advice from this blog, I removed the resistor, three surrounding capacitors and the transistor Q6. To my surprise the 22uF capacitors and the transistor were fine and only C18 was blown. The resistor showed 820 Ohm even if it was badly burnt. That probably saved the other nearby components. I ordered the replacements for all parts I removed and I ordered a ceramic 10W resistor. The PA was working! But the new 10W resistor was hot. I could not believe that the Klipsch actually used a tucked in 3W graphite resistor. No wonder all glue close to the resistor was dark brown. Poor capacitors must have been cooking. That is one really bad design. I left the resistor in the air and made a simple enclosure out of copper strip and fastened it to the aluminum heat sink. Now the resistor was just warm. Not pretty, but it works. I am testing the unit before I plan to put it all together. 

One more thing. Someone said that the resistor is hot even on "auto" setting. Not with my sub. If I set it to auto, the sub goes on as soon as the AVR starts playing a surround sound. If I turn the AVR off, the green  LED goes off after  10-20 minutes and the resistor cools down completely. So, the unit is not working when there is no signal and it is set to "auto".

Good luck with your repairs.

BTW no help from Klipsch or their main service. They just want to sell a new unit to me. They did not want to give schematics to me. 

[zajin]

Hi guys!

I have recapped a R-115SW amp, and replaced 2 burned resistors, but I still have issues.

The amp fires up and works for 1-30 minutes before it shuts down. Needs a power cycle (mains) so get back on.

 

I found ZD4 shorted, and ZD7 is suspect (I measure 65.5V over ZD7, same as the power coming from the PSU).

These are the 2 Zeners close to the board edge, next to the power connector.

 

If one of you could measure the voltage over these 2 zeners for me, that would be super helpful!

 

Edit: I also found a burned tiny transistor, in the same chain. Seems to be marked G1 on the component. Maybe Q2 on the board. Any info on this would also be great!

Edited January 16, 2023 by zajin
more information

[JensK]

Hi everyone, 

since several days I have a similar issue with my R-112SW as mentioned before. The sub is shutting down after a few seconds if I turn up the gain control. Since this is already my second AMP Unit I don't want to buy a new one, so I opened the Sub and took a look at the unit.
My first approach would be to change the grilled resistor and its surrounding transistors. But after taking a closer look at the resistor the color code says it has 80Ohm. Is this possible or am I wrong with my color coding (Black-Grey-Brown-Gold) ? - I've attached a picture below. 
So maybe one of you guys can help me, I've read that the R-112SW has a 620 Ohm resistor is that true? 

It would be great if someone of you can help me! Thank you!

 

 

Edited January 18, 2023 by JensK
Changed image type

[zajin]

Remove the resistor and measure it, it's possible still within specs. But should still be replaced with a higher power one.

You need to replace all the electrolytics on the board, and remove all the brown glue/goop.

[Alain63720]

Hello I have a R-115SW not working (seems dead) 

What is the use of the connection CN5 on the PSU. Is to switch on/off the PSU? 

What voltage should we get at CN2? 

Thank you for your help 

Alain 

[JensK]

On 1/18/2023 at 10:13 PM, zajin said:

Remove the resistor and measure it, it's possible still within specs. But should still be replaced with a higher power one.

You need to replace all the electrolytics on the board, and remove all the brown glue/goop.

Thank you for your response! I’ve removed the resistor and the measured it. The result is 670 Ohm. Don’t know why the color is wrong or changed but now I can order the correct parts! 

[zajin]

45 minutes ago, JensK said:

Thank you for your response! I’ve removed the resistor and the measured it. The result is 670 Ohm. Don’t know why the color is wrong or changed but now I can order the correct parts! 

Color changes with the heat, it's burned off

[zajin]

On 1/22/2023 at 9:09 AM, Alain63720 said:

Hello I have a R-115SW not working (seems dead) 

What is the use of the connection CN5 on the PSU. Is to switch on/off the PSU? 

What voltage should we get at CN2? 

Thank you for your help 

Alain 

CN5 is +5VDC (it says so right on the PCB.. ). It's present even when the amp is off. It's most likely used as a control signal to turn the PSU on/off. You can jumpstart the PSU by connecting the +5VDC to CON/PSONOFF (leftmost wire on the 4-pin conenctor). Do so at your own risk!

 

CN2 has +/-62V, center pin is ground.

 

[Justdigit]

Hello....

 

I hope pleaee someone can help me

 

My sw115 wouldnt switch on. I have replaced the resistor and two capacitors. But I see a third resistor burnt. 

I don't know the value can someone point me in the right direction? It's the one closest to the relais

 

Thanks in advance. 

https://ibb.co/2PLbbYH

 

 

 

 

 

Edited February 2, 2023 by Justdigit

[BillL001]

Hi All, 

 

After reading this entire thread, as well as watching Mr. ngen33r's 3 repair videos on reparing the R-115SW subs, here's what I can tell:

1. The failure of the amp board is very common on Kilipsch's subs, not only happens to one particular model but many, and the number of failures are very large. 
2. The repair services by Mr. ngen33r seems to be going very slow, if moving forward at all.  Based on vidoes, it looks like it takes little over an hour for ngen33r to repair an amp, so if even if he only works on this on the weekends and repairs a few per weekend, he should be able to fix around a dozen per month. But the waiting list shows that folks requested as early as more than 2 years in Dec. of 2020 are still waiting his sub to be repaired, so may be ngen33r no longer does the repair now. 
3. I have a R-115SW with a failed/burned amp, and it seems there's no scheamtic or complete parts list for all the reistors and capacitiors needed to repair this particular sub's amp.  

 

So my questions are - if any of you know the answer, please offer your comments:

1. Does ngen33r still perform his sub repair services? If not, other than a few on eBay, are there any reliable repair services we can use? Klipsch doesn't offer the repair, unfortunately, and when I called them asking for the options, their tech suppoprt says the only thing they can offer is for me to buy a new amp from them for $300+.   
2. Is there a complete lits of resistors and capacitors to replaced the burned ones on the amp?  For those of us having the solders and other tools, we could potentially try to replace the bad resistors and capacitors, only if we know the complete list of these parts and their specs, which unfortunately, from what I can tell from either this thread or on ngen33r's website, it's not available. The only thing I can see is it's in the 2nd R115SW YT vuideo for a few seconds at 1:16:11.  Can someone confirm these are all the parts we need?  Any recommended brand for good quality of these p[arts, and a good online store to buy them (Amazon)? 

 

Now, related to my particular R-115SW sub's problem, may I ask if any one can comment on what I see on the amp board?

 

1. Where I marked area 1, circuled in red, these seem to be the main failure of that burned resistor, right?

 

2. Where I marked area 2, circuled in blue, there are some glue alike brown stuff at the bottom of the two capacitors, are these factory glues that are supposed to be there, or the melted chemicals ozzed out from the burned resistor or the small cap next to it?  What do you see on your amp board under these two large caps?

 

3. Where I marked area 3, circuled in green, on top of these caps, there's this layer of brown stuff, are these factory glues that are supposed to be there, or the melted chemicals ozzed out from the caps below?  If they are factory glues, I supposed I can leave them there and not replace these caps. What do you see on your amp board above this group of small caps? 

 

Lastly, if you have repaired your amp board, what reference did you use to tell what specs of the resistors and caps at each spot on the board?  In case where the lables on the board are covered by those ozzed on chemaicals, we will have to clearn them up before we can see the soldering spot lables, right? 

 

I wish there's a schematic or diagram showing the specs of each of these parts on the board, somthing Klipsch should provide to us but unfornaturely they don't.  Given the large percentage of their subwoofer customers will run into this problem, Klipsch really should provide us with a repart kit that includes the resitors and capacitors, and a diagram of these parts replacements, so we the customers who can repair by ourseleves could at least to give it a try, instead of paying another $300+ for a replacement amp board.  Paying almost 50% of the cost of buying a new product just for a a few replacement parts, this is like after you buying a $20 grand new car and it breaks down due to some bad parts, and the car company asks you to pay another $10 grand to get it repaired, which no customer would be willing to do.

 

Thanks everyone! 

 

 

 

[exscape]

On 1/28/2023 at 11:31 AM, Justdigit said:

Hello....

 

I hope pleaee someone can help me

 

My sw115 wouldnt switch on. I have replaced the resistor and two capacitors. But I see a third resistor burnt. 

I don't know the value can someone point me in the right direction? It's the one closest to the relais

 

Thanks in advance. 

https://ibb.co/2PLbbYH

Hello! That resistor is brown-black-black so 10 ohms. Mine measures about 9.8 ohms so that checks out! This is on a R-112SW though but I would assume they're the same.

 

I have a similar question myself. Just above the red film cap in the above photo (next to the electrolytic capacitor) is a zener diode, marked ZD5. Does anyone know the specs for this diode? Mine has been replaced by someone else, with a through-hole diode. I have no idea if it has the correct value or not, so I figure that *if* the amp doesn't work after the changes I have planned, I would have a look at that diode next.

My multimeter can't measure the zener voltage, but if someone posts a value I'll build a small circuit to verify it.

 

[exscape]

So I finally got the parts, time and energy needed to truly work on the amp, and finished today. I plugged it in and... it makes sound. But not the sounds I want it to make.

 

Listen here:

 

The speaker cone looks entirely new from the front. Could it still be the speaker that's broken, or is the amp more likely? If so, any advice on how to troubleshoot as I have *NO* idea what could cause this?

The noise is correlated with the bass in the sound playing. E.g. if you play a kick drum, you get a treble-y noise every time the kick should play.

 

Here is what a 85 Hz sine wave played though the sub looks on the SP+ and SP- terminals on the amp.

 

First, with a large timebase, to show the 85 Hz:

 

Then zoomed way in to show the noise that makes the 85 Hz line so thick:

 

Are these readings as they're expected to be, or broken?

Note the weird Vrms readings. The vertical scale is the same, so the noise is clearly far lower amplitude than the signal, yet the RMS voltage reads as about half. Peak-to-peak I'd estimate 20 V vs 4 V based on the vertical divisions alone.

 

Edit: So just after posting I realized I could actually test the speaker alone, by driving it directly from my AVR. Not the best idea, but I figure it's safe as long as you stay at low volumes = low power. Anyway, the speaker sounds like crap this way too, so it's most likely broken. Damn it, all this work and I'm still not done -- and perhaps I can't even find a replacement for a reasonable price.

 

Question 2: How warm is the back of the plate (near the output MOSFETs) supposed to get? Mine gets hot (over 50 C) in just a minute or two of testing, doesn't seem right. Perhaps it's due to the speaker issue? Is it meant to get warm enough that it's hard to touch, especially so quickly?

Edited February 12, 2023 by exscape

[BillL001]

On 1/12/2023 at 11:24 AM, Sinisa said:

Hi.
My 115 SW started to shut down after a few minutes of use. I found many useful advices in this blog and decided to open it and try to fix it.  R39 was all brown and the outer layer was flaking. 330uF /16V C18 was bulging and its rubber seal at the bottom was pushed out. Following the advice from this blog, I removed the resistor, three surrounding capacitors and the transistor Q6. To my surprise the 22uF capacitors and the transistor were fine and only C18 was blown. The resistor showed 820 Ohm even if it was badly burnt. That probably saved the other nearby components. I ordered the replacements for all parts I removed and I ordered a ceramic 10W resistor. The PA was working! But the new 10W resistor was hot. I could not believe that the Klipsch actually used a tucked in 3W graphite resistor. No wonder all glue close to the resistor was dark brown. Poor capacitors must have been cooking. That is one really bad design. I left the resistor in the air and made a simple enclosure out of copper strip and fastened it to the aluminum heat sink. Now the resistor was just warm. Not pretty, but it works. I am testing the unit before I plan to put it all together. 

One more thing. Someone said that the resistor is hot even on "auto" setting. Not with my sub. If I set it to auto, the sub goes on as soon as the AVR starts playing a surround sound. If I turn the AVR off, the green  LED goes off after  10-20 minutes and the resistor cools down completely. So, the unit is not working when there is no signal and it is set to "auto".

Good luck with your repairs.

BTW no help from Klipsch or their main service. They just want to sell a new unit to me. They did not want to give schematics to me. 

 

 

Good to know at least someone fixed his amp!   Could you share what's the spec of that FET (or MOSFET) right behind that burned 820 ohm R29 resistor?  You replaced that FET too, right?

 

What chemical cleaning solution or fluid that you use to clean up the glus oozed out from burned caps onto the board?

 

Thanks!