B&W PV1 Subwoofer - Guide for repair - help

Keefykeep

Novice Member
Hi

I found the fault with the PV1 i am repairing
It turned out to be the 470uF 16V capacitor (labeled C824), the ESR of this cap was over 20 ohms! (it was meant to be less than 1 ohm when new)

Why did it fail? probably because they used low temp, short life span SMG branded caps (85 degreesC at 2,000 hours) and it is close to other components that get quite hot, there is even a slight bit of heat caused discoloration on the small 2.2 ohm resistor (labeled R818)

I also tested the ESR of all the other SMG caps and they are also have higher ESR values above what they should be when new, but probably not out of spec enough to cause problems (yet)

The big brown nippon caps all measured low ESRs and are 105 degrees C rated

If you intend to measure the ESRs of the caps dont forget to discharge them via a resistor beforehand

I replaced the faulty cap with a higher operating temp longer life cap

Here is a link to an informative site about capacitors

If this cap replacement does not work for you, then check for dry solder joints, and also if needed, get a component tester (ie, Multi function Tester TC1 ) to test other components like semiconductors etc

+1 for the hair dryer tip,

cheers, and good luck

AND REMEMBER BE CAREFUL OF THE HIGH VOLTAGES THAT ARE PRESENT ON THIS EQUIPMENT!!

Read the safety first comment on this following link before working on the SMPS power board of the PV1
Troubleshooting switch mode power supplies
 

Zouzou75

Novice Member
Hi Thanks for your advise keefykeep
I replaced the c824 capacitor and yes the ticking noise stopped
👍👍👍👍
but no reaction only when I turn up the volume like you can see on this video

 

Keefykeep

Novice Member
Hi,
That might be normal operation, what is your test tone source? if you are using a smart phone (app or online) as a sine wave generator, it might not have enough voltage output to get the full volume level on the sub.
And what is your Hz setting on the sub?(on your video, I cant tell if its around 40Hz or 80Hz) if its set too low, it might be attenuating the bass signal you are putting into it (what frequency is your test tone?)

Good to see replacing the cap stopped the ticking :)
 

hansy

Novice Member
Hi i also have a ticking noise on my pv1
The power led doesn't works i think the problem comes from the power board
View attachment 1338839

Any idea to repair or replace the board thanks

PS: For People Who have problem to open the frame i easily open it with a hair dryer
91089845-6188-419A-9426-FBDC4AB5C2C9.jpeg
8255FC49-092E-483E-A873-76ED40424554.jpeg

Hello plsss help ... I use a hair dryer - but the bottom half wont open. How do I open it
 

Keefykeep

Novice Member
there are 4 more screws behind the circular metal plate that you have to remove, but first you have to remove some of the black sticky rubber sealant (inside the unit) from around the wires that go to this plate so that you have enough slack on the wires to move the metal plate to access the screws
 

hansy

Novice Member
there are 4 more screws behind the circular metal plate that you have to remove, but first you have to remove some of the black sticky rubber sealant (inside the unit) from around the wires that go to this plate so that you have enough slack on the wires to move the metal plate to access the screws

Thank you sooo much!! I spent the last two hours trying to open it lol - its the 4 screws.
i found a cotton pad thing (see pic) inside not sure where it goes.

Also the sub lights are on but nobodys home (feeding signal but no sound)
 

Attachments

  • 4AC91129-540D-4572-AB83-86943F696AE9.jpeg
    4AC91129-540D-4572-AB83-86943F696AE9.jpeg
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Keefykeep

Novice Member
the same cotton pad was also inside the one I repaired as well, not sure what its for, though it could be some sort of moisture absorber?
Does your sub have the ticking noise?
 

hansy

Novice Member
the same cotton pad was also inside the one I repaired as well, not sure what its for, though it could be some sort of moisture absorber?
Does your sub have the ticking noise?

Hey just wanted to thank you for your help - id buy you a beer if u lived close by.
My sub turns on lights are on. But there is no sound (i have another sub which i used as a test to see if there was signal)

no sound from either woofer. Do you think its a faulty cap. Or should i do the power supply (upgrade, as per the braun 12 v switch addition in the previous post)
 

Keefykeep

Novice Member
I guess you could try swapping the cap first to see if it fixes the problem, then if it doesn't you could go with the power supply upgrade.
Capacitors (especially electrolytic ) are usually the components that go faulty in amplifiers, etc..
If you have access to a capacitor (or component) tester you could test the capacitors and other components to help locate and fix the problem
 
Last edited:

hansy

Novice Member
Just an update guys, after testing all of the caps I found the b&w pv1 had a faulty amp board. The board in question is a bang & O icepower 500A. I contacted a b&w service center and they wanted an exorbitant amount. The gentleman was kind enough to chat and somewhat acknowledged the service price was a bit high, and that they have had to swap out numerous Boards due to issues with the b&o icepower 500A board.
I like the sub, visually its a piece of art. As for the internals (made in china drivers, low quality caps - these are rated at 2,000 hours 85 degrees( dont know why they didnt spend a little more on nichicon or chemicon caps)
And a crappy b&o icepower board.
Somewhat dissapointed in bowers, I hope this is not where they are heading with their more “affordable” range of audio gear. I definitely wont be purchasing anything from Bang & Olefson in this lifetime.
 

simac

Member
Hi, I have one of these that's developed the same issues, no sound, just clicking...I'm thinking it might be easier as a long term fix to just turn this into a passive sub, take out all the electronics...would that be easy from the looks of it? I wonder are the drivers wired in phase or out?

(I have a pretty advanced DSP for EQ/Crossover anyway and so don't need any of the settings).
 
Last edited:

KEREGR

Novice Member
Hello, I would love for someone to photograph or write the values of all the main board capacitors. I've seen a few photos, but none of them show which capacitor it is and what its parameters are. if someone had this motherboard for sale or would sell a broken PV1 spear to it. Thank you all for your help.
 
Last edited by a moderator:

Robert dm

Novice Member
Hello, I would love for someone to photograph or write the values of all the main board capacitors. I've seen a few photos, but none of them show which capacitor it is and what its parameters are. if someone had this motherboard for sale or would sell a broken PV1 spear to it. Thank you all for your help.
16030469220368084815484598608533.jpg
 

Robert dm

Novice Member
That is what you ned spareparts.
For exampling the pv1 kabinet use 2 wrench iron at 30cm an fit in holes so the home made tool stick tru the kabinet an skrew 2 bolts at the wrench iron inside kabinet so that you skrew bolt so you force kabinet apart just do it the same lenght a bit on both till it seperate no hard work no fideling with heatgun plenty off power in the 2 tools you have made😀
 

hansy

Novice Member
Hi

I found the fault with the PV1 i am repairing
It turned out to be the 470uF 16V capacitor (labeled C824), the ESR of this cap was over 20 ohms! (it was meant to be less than 1 ohm when new)

Why did it fail? probably because they used low temp, short life span SMG branded caps (85 degreesC at 2,000 hours) and it is close to other components that get quite hot, there is even a slight bit of heat caused discoloration on the small 2.2 ohm resistor (labeled R818)

I also tested the ESR of all the other SMG caps and they are also have higher ESR values above what they should be when new, but probably not out of spec enough to cause problems (yet)

The big brown nippon caps all measured low ESRs and are 105 degrees C rated

If you intend to measure the ESRs of the caps dont forget to discharge them via a resistor beforehand

I replaced the faulty cap with a higher operating temp longer life cap

Here is a link to an informative site about capacitors

If this cap replacement does not work for you, then check for dry solder joints, and also if needed, get a component tester (ie, Multi function Tester TC1 ) to test other components like semiconductors etc

+1 for the hair dryer tip,

cheers, and good luck

AND REMEMBER BE CAREFUL OF THE HIGH VOLTAGES THAT ARE PRESENT ON THIS EQUIPMENT!!

Read the safety first comment on this following link before working on the SMPS power board of the PV1
Troubleshooting switch mode power supplies
Hi,
Do you have any experience with the Panasonic FC or FR series caps? I have repaired my unit, but I now intend to replace all of the caps (these Chemi-con SMG caps are crap)

Ideally I would like the Panasonic FR series as they are long life/ high temp - my only issue is that they are very low ESR and Im not sure if that will cause any issues with sound or overall stability
 
Last edited:

DodgeTheViper

Moderator
It's far easier for the poster to do the translation rather than the individual reader having to do it. So that would be one translation vs however many people wanting to read the post translating it.
 

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