Polk PSW111 sub-woofer - Heartbeat
niceguy
Posts: 2
I wanted to post an issue that I found with the PSW111 sub-woofer. When the power is plugged in without any input, you hear a heartbeat noise from it. I was able to get an engineer friend from work take a look at it and narrow it down to 2 capacitors on the board. This was my second sub-woofer with the exact same issue. I am not sure if its a well known issue, but I thought I post it here. He helped me replace those capacitors and the heartbeat was gone!
My friend asked me to post this finding on here in hope that it will help someone with this issue.
Here is the spec of the capacitors and a link to one source.
47uF
63V
105°C tolerant
.2” (5mm) lead spacing radial aluminum electrolytic.
Mouser Link
I have highlighted them in this image. (This is not my image, I found it in google search)
My friend asked me to post this finding on here in hope that it will help someone with this issue.
Here is the spec of the capacitors and a link to one source.
47uF
63V
105°C tolerant
.2” (5mm) lead spacing radial aluminum electrolytic.
Mouser Link
I have highlighted them in this image. (This is not my image, I found it in google search)
Comments
-
Hi,
the same happened to me and more people, as can be read here. I bought the capacitors your friend recommended, thanks!
But when I was replacing them I noticed that a capacitor was bulging, the bigger one on the bottom left (highlighted on the image below, from the link above). It is a 100uf 25v bi-polarized capacitor (CD71H). I checked all the images I could find of the board, and on all of them the cap was polarized, so I took my chances and replaced it with a polarized equivalent. I now it may not be a good idea, but for now it works. Hope it helps someone!
-
Thank you,
I didn't notice this until you mentioned it. It looks like there 4 non-polarized electrolytic caps used on mine.
C20, C48, C53 4.7uf 35v
C41 100uf 25v that you mentioned.
I don't think any of these are the cause of the amp motorboating but it's good information to note for anyone replacing all the caps.
-
Thank you so much
My subwoofer is working now -
You're a lifesaver! My PSW111 would cut off during heavy action scenes in movies, occasional heartbeat, etc. Replaced those 2 capacitors and its playing as loud as new. Thanks for the info!
-
Polk needs to accept their subwoofers doing this and fix/replace them. This is apparently a rampant problem with Polk subs!
-
Thanks for the tip. I replaced the two caps listed and my heartbeat problem disappeared! What did you guys use to replace the "glue" that was holding down all the board screws?
-
Hot Melt Glue works and won't corrode anything.
-
Same “heartbeat” issue with my PSW111. Bought in 2013 and started acting up 2 days ago. Upon inspection there were no visible signs of damaged caps but I figured it was worth a try. Some gas and $1.50 for both caps as noted above resolved the issue. Saved me hundreds for a new sub! Many thanks!
-
I'm not an electrical guy, but my sub had stopped working. The attached pictures shows the same capacitors as the picture above. Does this look like a capacitor issue?
-
Another angle.
-
Your note is a life saver. I have a same issue, and it is driving me crazy. Now I knkow how to fix it.
-
I managed to replace the capacitors without removing the board which seems to be really hard. For doing this, I bent the capacitors so that a little bit of their wire stays out, and then pulled them out, and soldered the new capacitors to those wires. Works perfectly in my case. Thanks again for your life saving discovery about changing these capacitors.
-
Hi! I’m new to the forum. I’m no expert trying to fix the “heartbeat” problem. I’ve tried to measure both mentioned caps above and the all read ok. They also look ok. Some other caps read 5.7uF and they are supposed to be 4.7uF. It’s that with in tolerance? Or reading caps on a circuit is just not reliable? The board seems to be ok visually, do you have any ideas? Thanks! Sorry for my broken English.
-
HI, just wanted to say that this post saved me the $150 that Polk wanted to charge me for a new amp for my PSW-111. All it cost me was the capacitors...well, and the excuse to get a better soldering iron. ^_^
Thanks! -
@jplamela While the capacitance -might- be far askew (in your example it's only barely beyond the 'typical' +/- 20% though), you really need an ESR meter to reliably test caps.
I'd had this issue and finally took everything apart and measured all the caps. I ended up replacing most of them, but they weren't all really necessary. The only visibly failed cap was the big 400v/100uF mama. The normally mentioned 63v/47uF pair were definitely bad (ESR >4ohm). The non-polarized 35v/4.7uF trio were ESR 2.2-9.4ohm. Finally, the 63v/10uF measured as open in-circuit, and 3.5uF/>15ohm removed.
However, after replacing all these (I also replaced the 35v/100uF and two 50v/47uF whose ESR was questionable), I was still getting the 'heartbeat'. But I had noticed something suspicious in my soldering expedition...
The transistor connection to the 35v/100uF didn't look right, as did testing continuity between them. So I soldered some leads to both sides and did some testing. Long story short (pun intended), that trace had been fried. Connecting them made the sub amp work a-ok; it has been working fine for a few weeks now. ;-) I suspect some of those here (and at the hesiod blogspot) that didn't have success likely had this same issue.
I simply cut a tiny chunk of phone wire and shunted the burned connection; by the 'D8' transistor in the following pic. Note: the 63v/10uF cap straddles the 'D8', and the 35v/100uF cap is left of that cap with one lead connected to the transistor shunt. If you find you need to do this too, ensure the 63v/10uF doesn't short to the transistor.
-
This seems to be a common problem, and it just happened to me. I don’t have the skills or tools to do the repair described here. @polk are you offering an affordable solution to older customers on this? Are there really only 3 service centers in the country? https://www.polkaudio.com/en-us/support/servicecentersearch
-
I recommend sending an email to Kim.Jasper@soundunited.com
-
Another satisfied customer, thanks to all who contributed to this! I wasn’t confident this would work since my problem wasn’t a “heartbeat”, I just wasn’t getting any audio at low volumes, but if I really cranked it, something would come out (not sure if it was right, but something). Bought these two capacitors and it seems good to go!
-
Thank you,
I didn't notice this until you mentioned it. It looks like there 4 non-polarized electrolytic caps used on mine.
C20, C48, C53 4.7uf 35v
C41 100uf 25v that you mentioned.
I don't think any of these are the cause of the amp motorboating but it's good information to note for anyone replacing all the caps.
Must be non-polarized, at least the first three, they are on the signal path
-
Hi! I’m new to the forum. I’m no expert trying to fix the “heartbeat” problem. I’ve tried to measure both mentioned caps above and the all read ok. They also look ok. Some other caps read 5.7uF and they are supposed to be 4.7uF. It’s that with in tolerance? Or reading caps on a circuit is just not reliable? The board seems to be ok visually, do you have any ideas? Thanks! Sorry for my broken English]
Normally, standard capacitor could be 4,7uF or 5,6uF (my english is worse then your
)
-
Hi,
the same happened to me and more people, as can be read here. I bought the capacitors your friend recommended, thanks!
But when I was replacing them I noticed that a capacitor was bulging, the bigger one on the bottom left (highlighted on the image below, from the link above). It is a 100uf 25v bi-polarized capacitor (CD71H). I checked all the images I could find of the board, and on all of them the cap was polarized, so I took my chances and replaced it with a polarized equivalent. I now it may not be a good idea, but for now it works. Hope it helps someone!
Are you sure? From the schematic seems can be non polarized, it receive positive or negative voltage from on-off circuit control
-
The problem with this plate amplifier is that even when it is OFF or in standby it is always powered and the capacitors age prematurely, would be wise to disconnect it from the mains when not in use. Having said that, the problem on my PSW110 is more serious, together with the heart pulse the output is very low and distorted, from the tests I have done it is not the capacitors, or at least not only those, the voltages at the output of the power supply are too low , I tried everything, remain to try to replace the Mosfet that drives the transformer. After this attempt, the last hypothesis that the oscillator little board soldered to the pcb is faulty, but obviously it cannot be found and I will have to change the plate amplifier. Other solution is supply it from the outside, for make it I have the schematic but there is not into the voltage needed for power stage.
-
I just can't imagine spending this much time an energy trying to repair a subwoofer that was originally $250.
-
I just can't imagine spending this much time an energy trying to repair a subwoofer that was originally $250.
If the problem is only two capacitors, replacing need half hour of time and 2 dollars of cost. Not everyone finds $ 250 on the floor, but if you are rich and have this sub problem, send me the amp and I will fix it for myself , because unfortunately the problem on my amplifier plate is not caused by those capacitors, but it is much more difficult to solve, expecially without complete schematic of Sonavox parts
-
My time and sanity is worth spending more than $250 on a sub that won't **** the bed after a few years.
If you spend more up front, you get more in the long run. For example I have a Velodyne CT-100 circa late 1990s that still works perfectly. -
My time and sanity is worth spending more than $250 on a sub that won't **** the bed after a few years.
If you spend more up front, you get more in the long run. For example I have a Velodyne CT-100 circa late 1990s that still works perfectly.
I have also a BK Electronics with 275W RMS linear amplifier and Peerless XLS subwoofer in a sealed box, very similar to a REL classic sub, a little bit better than your, but this no mean I must throw away the polk, if it can be reapaired with 2 dollar. Unfortunately the problem on my polk is more serious than 2 capacitors -
Upgrade, i have replaced one mosfet and all power supply capacitors, less than 10 euro of tutal cost, and the sub run well now. I have fixed also an additional heatsink and built a small external circuit with a 5V relays, which turns on the sub only when I turn on the stereo amplifier or the AV receiver, because the problem with these subs is that while remaining in standby, the power supply is always live.I believe that now the sub will be able to survive for many years
-
I believe that now the sub will be able to survive for many years
Keep a happy thought..
-
ken brydson wrote: »
These subwoofers, PSW111, PSW110, PSW125 and similar that use a plate with BASH amplifier (I don't like the topology of amplifier because it is more critical), have three main problems, they are always with power on, they use poor quality electrolytics, and they have an undersized heatsink. By correcting these problems there is no reason to think they can't run for years without problems. Obviously not everyone is able to operate all the necessary moddings and they are not electronics technicians, but at least everyone can prevent them from being always on using an external power switch, this would make them work properly much, much longer -
I know this is a little late to the game - but I wanted to share my experiences. I have extensive background in electronics including circuit design and manufacturing.
The main issue is the choice of capacitors chosen by BASH when they designed the amp. Capacitor lifespan is a complex issue. If a capacitor is rated for 1000 hours @ 105C, we think ok, this is great. The application will never see that temperature. But that is not true. This temperature is the INTERNAL capacitor temperature which is effected by ambient temperature AND self-generated temperature. As capacitor charge and discharge, they generate internal heat. When this heat crosses the max threshold, there is the possibility of electrolytic boil-off. Sometime this is slow, and the cap appears fine, but doesn't work. Other times this is extreme and you will notice either a bulge and/or visible electrolytic leakage.
I chose to replace ALL of the electrolytic capacitors last year on 2 out of 3 amps (I have 2 subs, but had an extra amp that I replaced the first time I had the issue). Using the schematics and the datasheets from the original capacitors, I was able to match ripple/esr on the replacement caps and over a year later the units are still running great! I made no other modifications. No complicated on/off switching and no additional cooling.
This is the list of capacitors that I replaced:
C14 replaced with Panasonic EEU-FS2A121(L) or (B) - both work (120 µF 100 V Aluminum Electrolytic Capacitors Radial, Can 10000 Hrs @ 105C)
C24 replaced with United ChemCon EKXJ401ELL221MM50S (220 µF 400 V Aluminum Electrolytic Capacitors Radial, Can 12000 Hrs @ 105C)
C12 replaced with RubyCon 100YXM10MEFR6.3X11 (10 µF 100 V Aluminum Electrolytic Capacitors Radial, Can 10000 Hrs @ 105C)
C22, C41 replaced with Würth Elektronik 860240675007 (100 µF 50 V Aluminum Electrolytic Capacitors Radial, Can 10000 Hrs @ 105C)
C3,C7 replaced with RubyCon 63YXJ47M6.3X11 (47 µF 63 V Aluminum Electrolytic Capacitors Radial, Can 7000 Hrs @ 105C)
C38,C39 replaced with Würth Elektronik 860040774002 (47 µF 63 V Aluminum Electrolytic Capacitors Radial, Can 7000 Hrs @ 105C)
C20, C48, C53 replaced with Nichicon UEP1J4R7MED (4.7 µF 63 V Aluminum Electrolytic Capacitors Radial, Can 1000 Hrs @ 105C)
I hope this helps anyone else with the same issues.
