Repair costs total $10-$15 if you do the work yourself. I imagine a shop in your area would charge around $100. You can have them watch this video to save them the time of figuring out the circuitry. Good luck!

@@dennisbsutube much appreciated.

I spent around $10 with Digi-Key to get the parts I needed for this fix. Sorry, I retired from the high-end audio repair business many years ago. If you send a link to this video to a real electronics repair shop near you, they should be able to tell you if they are up to the challenge. Thanks for watching. Let me know if you find a good shop in your area.

Thanks! I'm glad I was not the only one that has not seen this choke configuration before. You're correct about keeping the block clean and oiled! No reason for it to let you down.

Don't give up hope! You can easily fix that noisy volume control with a can of Deoxit spray. Seems a bit expensive, but it works. We used to refer to it as "Technician in a can". Good luck. www.amazon.com/DeoxIT-D5S-6-Contact-Cleaner-Integrated/dp/B0002BBV4G/ref=sr_1_3?crid=2TQK06OFMMLB0&dib=eyJ2IjoiMSJ9.mZSBTPn6OJN80ue1is4spL_kTTxEAPCGlfICUKsMzNXeP7VOq9qDQaybKSu0bYJkG9XarPGqtonyKxKYJkRlxpMQPvJmN3QtMsrNGGORSMfPJpXQVSokF_f2t-c4AmW6aZx9LjnUomgYHOIV8Z2jbimWtRA9qPGZ26C-oCh_uk9i780ArwzHMTFEsv1y6vx1z4CA13zyGuoqNXOt0L2sPsjnEb2dA236hTIHfMaxFNrLmphCsKA-YfUgdavCnSB1hLqaC6Ry_2Z5WvSmCQqbTfX9d0Bb_hQO8qBeJ0LFTf4.P5lWH6nYagQJV80YEy5BYydtp-U1o-5WFZOw868ojD0&dib_tag=se&keywords=deoxit&qid=1710771086&s=musical-instruments&sprefix=deoxit%2Cmi%2C106&sr=1-3

Thank you so much for your kind words! I try to pace my videos so beginners won't get lost, and "old pros" won't get bored.

Stephen, sorry for the late reply. I have been out of town and my phone would not navigate to the comments section. I appreciate your comments. Getting back into the repair business would require creating an entity, liability insurance, tax returns, etc. No thanks. I happy to share my knowledge. Find an electronics shop in your area and have them watch the video. I bet they will be able to fix your sub once they know what supply voltages to look for.

The freeze spray trick is only used when you have a part, typically a semi-conductor, that consistently fails after a circuit has warmed up. The freeze needs to be instantaneous and extremely cold to shock the part back into a temporary working condition. If you have a can of compressed air that will expel freon when turned upside down it might work, using a can a freeze spray is the best option.

Always fun to pass on some of the tricks we used back in the day.

Glad to help.

Ravi, The unit does have an audio detection circuit that powers on the amp from a standby mode. I'm pretty sure most of this detection circuit is located near the input area of the main amp board. The small transistor that I replaced near the end of the video was part of this circuit. The small electrolytic caps and any switching transistor involved in this circuit are most likely the culprit.

Dexter, The strange noises are a good indication some of the caps are going bad. Also, check the solder joints on the larger power resistors. There should be no measurable current on the heat sink. Disconnect everything from the subwoofer except the power cord, then measure to make sure the problem is not coming from another source. It does sound like you have a short or a breakdown in a semi-conductor insulator on the heat sink. This can be a dangerous condition. I would contact Polk customer support and ask for an amp replacement due to their liability exposure to injury in this situation.

Good for you. Persistence pays off!

Sorry, I retired from the repair business quite a while ago. I no longer have a business license or the needed insurance to do any work for the public. I'm sure if you took your sub-woofer to an electronics repair shop and have them watch this video they will be able to help you. Thanks for watching!

If you are missing both the +/- 57V supplies you need to go to the beginning of the switch-mode circuit, usually just after a coil type transformer. You are better off troubleshooting this circuit cold (AC power cord disconnected) so you don't get shocked. The problem will most likely be an open semi-conductor or fuseable /power resistor. A tip would be to look up the part numbers on the Mosfets or other major semi-conductors, find the datasheets and hopefully an application diagram that will show you a schematic of how that component is typically used.

@@dennisbsutube I think I have a lack of knowledge about DC output from the power supply. When the power supply is disconnected from the audio amplifier at the 3-pin connection, I see only 14VDC on one leg. When I plug the power supply into the audio amp board, I see +/- 57VDC. However, if I disconnect that 3-pin connector from the audio amp board, DC voltage slowly fades away. Is there a current sensing feature that essentially shuts off DC output from the power supply if there's no demand load? If yes, then my power supply is working fine and the problem lies on the audio amp board. At any rate, I still have the "heartbeat" after replacing all caps. I get a red power LED when the speaker is not attached; however, as soon as I attach the speaker, the power LED goes dark and the heartbeat returns.

Robert, disconnecting live power supplies to isolate problems is not a good practice, especially when dealing with switch-mode power supplies. Newer power supply designs can depend on feedback loops or an expected load to oscillate properly. You are always fine to check components when the main power source (AC) is disconnected, or live if you understand how to safely do that. Please remember that the PSW505 also has an audio detection circuit that turns the amp on/off. This could also be the source of your problem. If there is a cap in this detection/switching circuit that is off spec, it could cause the heartbeat symptom that you are experiencing. As I recall, most of this circuit is on the main amp board. Pull that board, put it on your bench, and start testing the components on it. Do you have a component tester, multi-meter, or hopefully both?

@dennisbsutube Thank you, Dennis. Learned what a switch-mode power supply is and that is indeed why I'm seeing the DC volts drop when the power supply isn't connected to the amp board. I'll stab the back of the 3-pin connector for future measurements. Replaced all the caps on the amp board but have pulled it and will learn more about testing the various components. I have an ESR meter and multimeter. Might consider getting a multi-component tester. I don't want this one to beat me!

Sorry, I retired from the repair business quite a while ago. I no longer have a business license or the needed insurance to do any work for the public. I'm sure if you took your sub-woofer to an electronics repair shop and have them watch this video they will be able to help you. Thanks for watching!

Thanks. Please know that any ESR meter is better than no ESR meter! Good Luck.

Glad to help!

@@dennisbsutube thyank you sir

There are a lot of opinions on this topic. I think the most important thing is the manufacturing quality of the cap to begin with. Stick with buying known brand names from a respected national distributor. Also, store your electronics in a decent environment, not a hot attic or damp basement.

Yes. As I mentioned in the video, when dealing with a plated through-hole, add some fresh solder to the joint before trying to remove the old solder. This wll make the solder more liquid based when heating the joint and allow a "solder sucker" to quickly pull the solder from the joint.

@@dennisbsutube Can you recommend a solder sucker? My bulb one does nothing. It's very frustrating.

The original Soldapullit made in California. eBay www.ebay.com/itm/272727193003?epid=28042051685&hash=item3f7fceb5ab:g:hnYAAOSwRsJeMuS5&amdata=enc%3AAQAHAAAAoNW4I58Dz34yoRzYrzMcJKOoE23WGxjFPK8QhiAc2UOs58vMcVcwOjtS8pRzFDdkJIQuxPHVKnurqQnyHlhp%2BGVEnDo5LaLR0vIxZ4GjQna9KPL0h9a9lwaWqcoimWCXMmEKUWGFfisD7c6XtbEf4a5W8ZgDDynafoiBZ95YIc23L%2FPefLFLdC4NkjgsNMAPwRPr9de64yegolMKsBpFNVs%3D%7Ctkp%3ABk9SR9br27iuYQ Amazon: www.amazon.com/EDSYN-The-Original-Deluxe-SOLDAPULLT/dp/B006GOKVKI/ref=sr_1_5?crid=13PK2RDC90ZFB&keywords=soldapullt+solder+sucker&qid=1672680718&sprefix=soldapullit%2Caps%2C103&sr=8-5

Make sure you keep the rubber o-ring and tip lubricated with white lithium type grease.

When dealing with older electronics, electrolytic caps can be a common problem. When trouble-shooting newer equipment, semi-conductors such as voltage regulators, IC's, rectifiers, and transistors are more likely to fail versus caps.

@@dennisbsutube I noticed on my newer motherboards they use all-metal caps. They don't swell or leak, correct? So, then you can't visually see which ones need replaced?

@@CarsandCats They are actually made with aluminum cans. Even they will "dome-over" if they need to release pressure. That is why you will sometimes see a serrated top to allow it to bend up, not break.

Great! Thanks for the positive comment

Glad you found the video helpful. Thanks.

If you only occasionally do troubleshooting, an inexpensive ESR meter is better than no meter. Search on eBay for : LCR-TC1 Transistor Tester ESR Capacitance Meter Electronic Component NPN PNP. About $25.00. Is your main supply (+65 and -65) down to 14.4, or is the 15 volt supply low?

​@@dennisbsutube Yeah, I'm thinking it's worth it. The 15v supply lines (+ and -) are exactly15v, but the +57 and -57 are +14.4 and -14.4

@@dirtfpv I have the exact same issue! Did you ever find a fix?

@@ehss192 I ended up buying a new one but I still want to work on fixing this one. I bought the esr meter though.

@@dirtfpv I see that same issue...the power supply output is at 14.4VDC when it is disconnected from the audio amp board (the 3 wire connector), but appears to be at +/- 47VDC when connected to the audio amp board. I'm wondering if it has some sort of current sensing feature that shuts down DC power output when there's no demand current.

Thanks. One must always respect the potential of switch-mode power supply, especially one with an AC cord.

Polk does not have a service manual, schematic, or even a block diagram available for their sub woofers. They do a horrible job of supporting their products with their end customers.

Ha! I appreciate your comment but after spending 25 years in consumer electronics repair, and the next 25 years in video surveillance manufacturing, I'm ready to go fishing!

Wow...that makes u a happy 70 yr old treasure trove of troubleshooting resource that is going to recede into oblivion. Seriously, u need to continue making videos to educate. Especially loved the tip abt the refridgerant. A lost art revived!

Thanks! There are a lot of "board jockeys" out there these days. I'd like to make more trouble shooting videos when I get the opportunity. I have a Bang & Olufsen Beomaster 8000 receiver waiting on me!

Sorry you are having a problem. If you are working on a PSW505 there are no other screws that I can remember other than the ones around the edge of the panel that need to be removed. Perhaps the plate is just sticking to the cabinet and needs to be popped loose with a sharp metal edge such as a putty knife.

@@dennisbsutube - Okay, I'll try that, but what about the other 13 smaller screws more on the interior of the back panel? Would those be causing the panel to stick? However, I noticed in your video that they're still on the rear panel even after you removed it.

@@dennisbsutube - Also, yes, mine is a PSW505 and makes that exact same horrible sound.

The smaller screws inside the perimeter hold the power supply, amp, and pre-amp boards to the back panel.

@@dennisbsutube - Okay, I got the back panel off with a paint scraper, however, Polk wants me to test the driver. However, my wires (unlike yours in the video) are on a very short leash and I can barely remove the panel out of the way to get to the driver. Also, I called Polk customer service, and all the girl could do is to tell me that she could send me instructions, even though, I told her that I already had instructions. 😫 But I don't know if this would make an difference, but here are the instructions that Polk emailed me, even though, I can't get to the driver. So, is there a trick to it? There is a simple test to figure out if the amplifier or the driver is the issue. 1. Unplug the power cable from the subwoofer. 2. Remove the grille from the subwoofer. 3. Take out the screws that hold in the driver of the subwoofer (some models will have a foam ring covering the screws, just peel this away). 4. Once removed, there will be two wires connected to the driver, positive and negative. Pinch and pull the connectors off. 5. Take speaker wire from your receiver and directly hook it up to your driver. 6. Keeping it at a lower volume, play audio and see if the driver functions. It is not going to sound great being outside of the box, but we are testing for functionality. If the driver works, the amplifier is the issue. If the driver does not work, the driver is the issue. Kindly reply back to this email once done with the test so we will know which part needs to be replaced.

I appreciate your comments. There are plenty of basic electronics videos on KZbin. Start with the easy stuff and work your way up. You'll be a troubleshooter before you know it!

Thanks!

Thanks! I'm glad you found it helpful.

1) Does the LED on the subwoofer stay RED, or does it turn GREEN? 2) Do the speakers work when connected directly to your stereo receiver or amp?

@@dennisbsutube mines just stays red and whenever it foes turn green it will only play got a little before then shutting off.

@@dennisbsutube I would really appreciate it if you could be any type if help. Ill even go as far as sending it out and paying you to fix it.

Sorry you are having trouble. Looking at the video I did not have to do anything unusual to remove the arm. Were you able to remove the nut on the motor shaft, or is the arm itself stuck on the shaft?

@@dennisbsutube Finally got it. Think it was actually glued on. Thanks.

The values of a cap are printed on the cap itself. Example: 22uf 35V would be a 22 microfarad 35 volt capacitor. The link to Digikey is to give you a source to buy the parts.

I appreciate your confidence, but I have been retired from the repair business for 25 years (a prior career). A good bench tech should be able to help you after he watches this video. Knowing what the voltages should be coming out of the power supply will be a great help to the tech. Good luck!

Thanks! I appreciate the positive feedback.

Unfortunately there is no guaranteed answer to your dilemma. The parts list that I showed in the video only totaled around $15 as I recall. I checked with the owner of the unit and it is still working fine. Who knows if it will last 10 more days or 10 more years. It's worth a try if you have the time to spend on the project. Good luck!