Your Digital Media Has Never Looked So Good

 
S80_UK
Posts: 1035
Joined: Wed Oct 25, 2006 3:11 am
Location: Cambridgeshire, UK

Re: PSU Dissected for Repair

Sat Oct 02, 2010 2:46 am

Steggl wrote:
Thank you very much guys. I exchanged the capacitor yesterday thanks to your how-to and now she's back to life. Man, I did miss her :D

Steggl wrote:
When the WiFi starts up it usually hangs or forces the Soundbridge radio to reboot. Maybe the soldering points weren't as good as I though..!?

Normally, you need to do more than just changing a capacitor. Other components are also likely to age, other capacitors, resistors, etc, and the compound which has been used to provide mechanical security is also known to become conductive so that it can modify the effective values of resistors and so on. The guys that regularly rework these supplies frequently change quite a few parts and make sure that the burnt compound is removed.

It sounds as though your supply is improved from its previous state, but may still be struggling to deliver enough current reliably, hence the rebooting that you are seeing..
Roku M1000, M1001, M2000, R1000, Roberts WM-201, Stream 83i
 
g0pkh
Posts: 350
Joined: Sat Jan 21, 2006 12:04 pm
Location: Essex Nr. Stansted Airport.. UK

Re: PSU Dissected for Repair

Wed Oct 06, 2010 7:05 am

Normally, you need to do more than just changing a capacitor


Ha ha. If only it was as easy as that.

The guys that regularly rework these supplies frequently change quite a few parts and make sure that the burnt compound is removed.


You hit the nail on the head there Les :)

At last count, for my rebuilds it is no less than 26 components :shock:

Pete
Soundbridge and Photobridge repairs offered.
contact via PM or hillyp02-roku@yahoo.co.uk
 
Steggl
Posts: 5
Joined: Fri Aug 15, 2008 2:37 pm

Re: PSU Dissected for Repair

Wed Oct 06, 2010 11:19 am

Dang! 26 parts? Now why don't you tell which parts I'd need?? It must be easier to get a hold of a new PSU from China, right?
 
g0pkh
Posts: 350
Joined: Sat Jan 21, 2006 12:04 pm
Location: Essex Nr. Stansted Airport.. UK

Re: PSU Dissected for Repair

Thu Oct 07, 2010 4:56 am

Well yes, but even if you were able to get a new PSU from China
It would suffer the same fate before very long.

Regarding parts to be changed.
Its all capacitors and all components in the feedback circuit too, in fact ANY parts covered in that wretched glue.

You need to remove ALL traces of the glue where it is discoloured, and replace any components covered by it.

Pete
Soundbridge and Photobridge repairs offered.
contact via PM or hillyp02-roku@yahoo.co.uk
 
ngcguy
Posts: 3
Joined: Mon Nov 22, 2010 7:32 pm

Re: PSU Dissected for Repair

Mon Nov 22, 2010 9:39 pm

The information on this forum is nothing short of amazing, thank you! You posted excellent information on the common cause(s) of Roku R1000 failures, particularly the info about the PSU failures.

We had our R1000 for about 2 + yrs when I woke up one morning and my wife’s Roku wouldn't turn on. Strange I thought, since it worked so well last night. She absolutely loves this radio and I knew this was suddenly a priority.
With Google’s help I located the Roku forum and read everything I could get my eyes on about the frequency of PSU failure and failure modes.

I opened up my Roku with great difficulty; in fact it took an hour or more to get it open. I removed the PSU and decided not to repair it, mainly because of posts about repeat failures some months down the road. An external power supply would be easier to replace if ever required and it would keep the heat outside of the radio. Yes, I hate those cubes but I’ll hide it as best I can.

With 19V and 9.8V recommended by the manufacturer, I choose the following parts. By the end of the day her radio was up and running with absolutely no difference noted in sound quality or volume … wife happy, case closed.
I wound up using the following parts to supply the required power:

Radio Shack PSU (RSPSU)
Enercell 15V / 1000mA AC Adapter
Model: 273-332 | Catalog #: 273-332
$27.99 (including one adapter tip)

Radio Shack
Enercell Adaptaplug M (tip)
Model: Adaptaplug M | Catalog #: 273-344
$6.99

Radio Shack
Size M Panel-mount Coaxial Power Jack w/Switch
Model: 274-1582 | Catalog #: 274-1582
(the switch was not used – that was the only part in stock locally)
$3.29

Radio Shack
Adjustable Voltage Regulator
Model: LM317T | Catalog #: 276-1778
$2.29

Homemade LM317 Regulator Circuit w/ heat sink
(very similar to circuit posted on this forum)
Input: 15VDC to blue wire | Output: 9.8VDC to red wire

The Radio Shack power supply (RSPSU) is regulated and filtered. No noise is apparent. With the radio playing, the new RSPSU is never more than slightly warm. The LM317 regulator circuit heat sink is moderately warm, noticeably warmer than the new RSPSU but by no means hot. I was concerned about the 1 amp rating but nothing larger was available. They do have an 18V version (also rated at 1A) of the same RSPSU that would work as well and may have some advantages I’m not aware of. I did experiment with an adjustable bench PS and tried both 15V and 18V inputs before making my choice. I could hear no difference in performance but the LM317 circuit ran warmer using the 18V supply and I could not see any advantage.

I mounted the LM317 on a small heat sink outside, on the back of the subwoofer cabinet. One advantage is that I can measure both the 15V and the 9.8V under load without opening the cabinet to do so … handy. I made no effort to reseal the subwoofer and I hear no difference in sound quality. That surprised me because I believed that this was a sealed sub when I started this project, only to discover that it was a ported enclosure later on. Now, I’m not an audiophile so you may well hear something (or not hear something) that I’m not aware of. But, to me, it sounds as good as it ever did.

I hope this is of some use to someone else with a problem that should never have happened. The design / location of the Roku PSU was bad from the git-go and the lack of Roku taking responsibility is disappointing. Thanks again for the idea of helping one another.
Last edited by ngcguy on Tue Nov 23, 2010 10:31 am, edited 1 time in total.
 
S80_UK
Posts: 1035
Joined: Wed Oct 25, 2006 3:11 am
Location: Cambridgeshire, UK

Re: PSU Dissected for Repair

Tue Nov 23, 2010 4:25 am

Good info, well posted. Could you edit your post to change the Roku model number since you are clearly referring to the R1000 radio and not the M1000 media streamer? Thanks.

Les.
Roku M1000, M1001, M2000, R1000, Roberts WM-201, Stream 83i
 
Burkhardi
Posts: 1943
Joined: Tue Jun 07, 2005 11:06 am
Location: Austin, Texas ...Y'all

Re: PSU Dissected for Repair

Tue Nov 23, 2010 6:02 am

ngcguy wrote:
. I could hear no difference in performance but the LM317 circuit ran warmer using the 18V supply and I could not see any advantage.

I mounted the LM317 on a small heat sink outside, on the back of the subwoofer cabinet. One advantage is that I can measure both the 15V and the 9.8V under load without opening the cabinet to do so … handy. I made no effort to reseal the subwoofer and I hear no difference in sound quality. That surprised me because I believed that this was a sealed sub when I started this project, only to discover that it was a ported enclosure later on. Now, I’m not an audiophile so you may well hear something (or not hear something) that I’m not aware of. But, to me, it sounds as good as it ever did.


Hello ngcguy,

Nice work, and glad it worked out for you too!

Please don't take this the wrong way, but let me give my point of view on two items (I use to be a sound quality judge, built many a woofer enclosure and I also have been in the industry since '89 and have repaired many a R1000 for forum members).

The sound output level of the unit is proportional to the input voltage to the amps, I have measures the output with the OEM 19 volt compared to the 12 volt (since so many try to use the 12v to power the whole thing) and you will lose output level/power using the lower voltage, it's even in the TI data sheet too. Even at 15v you will have a loss in total output, but it will not be as much as running it at 12v.
15 volts is almost 20% less voltage then what is called out. When you said you could hear no difference, do you mean in quality or level, the lower voltage will not effect quality but it will effect level. Did you run two R1000's side by side?

You may have gotten very lucky and the seal you broke acted like a gasket, but in most cases it will not. I seal them up very aggressively due to loose in sound quality and possible woofer damage. The woofer is custom made for this application, you have to have to seal it back up for the port to work correct. I have seen many an improperly sealed enclosure let the woofer flop around like a fish out of water. Not sealing the enclosure also effects the suspension since it's no longer dampened like it should be (like bad shocks in the car) and let the cone/voice coil bottom out and cause distortion too. Perhaps you don't have the power required to see this (since your using 15volts) but it can happen.

Once again, nice work and the bottom line is all that matters, if your happy which you seem to be, then that is all that matters.
Regards, Matt
Roku3 and Roku HD1000 [Rev B] on a Samsung HLP5674W DLP in the living room; a Roku2 and two Roku XS and a few SoundBridges.Win7; Kubuntu and XP via RT-N66U, E2000 and a switch or two. I own stock in Roku, it's just all in the form of hardware.Viva la Roku
 
ngcguy
Posts: 3
Joined: Mon Nov 22, 2010 7:32 pm

Re: PSU Dissected for Repair

Tue Nov 23, 2010 1:11 pm

Les,
Thanks for spotting that model number error … it has been corrected.
------------------------------

Matt,

I observed no change in sound quality. I agree that more volume would be available with 18V. We use it as a kitchen radio and generally set the volume between 35 and 45 depending on background noise level. In our application, we don’t notice the lower output power.

I agree that the design calls for a tight seal. Without that, results will not be predictable and will likely vary considerably from one repair to another. I planned to reseal the subwoofer if I observed any objectionable changes in sound quality, but only after I let the radio demonstrate reliability over a few weeks use. The last thing I want to do is to spend an hour or more prying it open again. So far it sounds fine to both of us. Just in case, what sealant do you recommend?

All,
Thanks again for sharing all your successes and photos. Without your input I probably would have discarded the radio and looked for a similar product from another vendor.

http://www.dropshots.com/ngcguy#albums/ ... 3/10:18:47
 
AW
Posts: 9
Joined: Sat Nov 01, 2008 2:36 am

Re: PSU Dissected for Repair

Thu Dec 09, 2010 3:37 pm

Hi,

I have the Pinnacle brand R1000 ... which died a few weeks back (out of warranty). I suspected the PSU due to the number of issues reported.

I have the PSU/bass unit open, and barring some discoloration on the "glue" all over the components, there is no visible evidence of failed components. One of the caps (100uF/400V I think) is squealing a bit.

When powered up, open circuit, the PSU outputs are reading 14.5 and 27 volts where they are nominally marked as 9.5 and 19 volts. I know this is not loaded but this seems quite a large over voltage.

I was considering fitting an external PSU and voltage regulator to replace the PSU, but probably won't bother if it is likely that the PSU has fried the main radio unit - not sure if that is likley at these voltages???

I have not looked inside the radio unit yet for signs of damage.

If anyone has any wisdom to empart as to what I should be looking for or any other advice, I would be very grateful.

TIA & Regards,

Alex.
Alex
 
ngcguy
Posts: 3
Joined: Mon Nov 22, 2010 7:32 pm

Re: PSU Dissected for Repair

Thu Dec 09, 2010 8:31 pm

Alex,

By “died” I assume you mean that it will not turn on. If this is not correct, the following may not apply.

You mentioned that one of the capacitors is squealing. Electrolytic capacitors (ECs) (look like small tin cans) can whine or squeal if they are failing. The failure is usually due to overheating and/or a poor quality capacitor.

To make sure that it is the capacitor that is making the noise, borrow a stethoscope or use a small tube like a straw to localize the sound source.

Examine the ECs on the PSU closely, looking for a slightly bulged top or signs of fluid leakage. That is a sure sign of pending EC failure. Just remember that a bad EC usually has a very slight bulge at the top … look hard and you will see it.

But let’s say that you do all this and do find a bulged EC. Is it worth changing? What else will fail a few months down the road? Many posts say that is exactly what happened after replacing that bad EC. Do you really want to reseal this speaker cabinet and possibly have to cut it open again later?

One suggestion: All you need is a (test) regulated power supply of 1 amp (or more) capacity and a voltage about 12VDC (you could even use a car or motorcycle battery).

Disconnect (cut or unsolder) the 4 wires from the Roku PSU. They are red, black, blue & black.

The 2 black wires are ground wires …. Connect them together and to the test PS negative terminal.
Connect the red and blue wires together and to the test PS positive terminal through a 5A automotive fuse.

Loosely reconnect (electrical connection only) the front and rear sections of the Roku PSU without using any screws. This need not be any kind of tight fit as it is temporary.

The Roku should turn on.

Assuming this is successful, you have confirmed that the Roku PSU is bad. Disconnect everything. No need to open up the front end unit as you confirmed that it works with your test.

Decide whether to repair the Roku PSU or eliminate it and use an external PS and voltage regulator instead.

Good Luck ..... ngcguy
 
AW
Posts: 9
Joined: Sat Nov 01, 2008 2:36 am

Re: PSU Dissected for Repair

Tue Dec 14, 2010 4:12 pm

Hi ncguy,

Yes, by "died" I mean it unexpectedly would not turn on one day, when the previous day it was fine.

Thanks for the knowledge on the diagnosing problems with the caps & suggestion about powering up off a single 12v supply - when I get a minute to check these out I will.

FYI I am leaning toward an using an external PSU & regulator, if it will power up at all now.

Thanks & regards,

Alex.
Alex
 
JohnBoyZ
Posts: 3
Joined: Mon Feb 28, 2011 2:20 pm

Re: PSU Dissected for Repair

Mon Feb 28, 2011 2:44 pm

I'd like to thank all those who have posted here, it helped a lot and I've now successfully repaired the PSU in my R1000.
Whilst I had the unit in pieces I thought I'd trace the circuit and have now created a PCB layout and circuit diagram which others might find useful, I don't know if I can post these files directly on this forum but I've stuck them on my website here

http://jfhelectronics.webs.com/soundbridgepowersupply.htm

Due to all the yellow encapsulation gunk I didn't get all the component numbers and values (especially in the mains input area) so if anybody can help fill in the blanks I'll update the diagrams
Cheers
John
 
terencegbg
Posts: 4
Joined: Tue Jan 13, 2009 12:01 pm

Re: PSU Dissected for Repair

Wed Mar 09, 2011 12:36 am

Hello, have finally open my radio and bought some parts however I do have an issue....

Here is my setup: http://www.ladda-upp.com/bilder/49747/koppling
Shows the psu (15V/1A) and the regulator to bring it down to 9,5V.

When I connnecy everyting EXCEPT the the blue cable for the power to the amplifier the display starts up just fine without any problem... however when I connect the blue cable it does not work, the diod/lamp starts to flash in the psu. (indicates someting i guess)

When I connected the blue cable to the red cable = both get 9,5V everything works perfect.... however 9,5V is I guess a bit pore for the amplifier.

Does anyone know why it does not work? thanks in advance!!

Specs psu: https://www1.elfa.se/data1/wwwroot/asse ... Data-E.pdf
 
JohnBoyZ
Posts: 3
Joined: Mon Feb 28, 2011 2:20 pm

Re: PSU Dissected for Repair

Wed Mar 09, 2011 3:23 pm

terencegbg wrote:
Hello, have finally open my radio and bought some parts however I do have an issue....

Here is my setup: http://www.ladda-upp.com/bilder/49747/koppling
Shows the psu (15V/1A) and the regulator to bring it down to 9,5V.

When I connnecy everyting EXCEPT the the blue cable for the power to the amplifier the display starts up just fine without any problem... however when I connect the blue cable it does not work, the diod/lamp starts to flash in the psu. (indicates someting i guess)

When I connected the blue cable to the red cable = both get 9,5V everything works perfect.... however 9,5V is I guess a bit pore for the amplifier.

Does anyone know why it does not work? thanks in advance!!

Specs psu: https://www1.elfa.se/data1/wwwroot/asse ... Data-E.pdf


Your circuit diagram looks fine so should work, I just wonder if the total current draw is exceeding the 1A rating for the power supply. Looking back through this thread the original power supply has a quoted max rating of
Output 19V, 2.3A
Output 9.5V, 0.37A

So there is quite a difference between 19v 2.3A and 15v 1A. Obviously the actual current drawn by the Roku is going to be less than the max figures but your supply at 15v 1A could be marginal. Have you measured the output voltage in the fault condition (with the blue wire on 15v) if it drops to zero then it could be the power supply is going into overload protection.
What happens if you just have the blue wire connected to the 15v (i.e. LM117 regulator disconnected) does the 15v stay OK,if so measure current is it drawing?
Then measure the current drawn from the power supply with just the regulator and red 9.4v wire connected (blue disconnected). Adding those two currents together should give you an indication of the total static current requirements.

Another thing to consider is initial current surge maybe there is high initial current surge (exceeding 1A) which is shutting down the power supply. You could try putting a switch in the blue wire so you can turn the power supply on with the blue wire switched off and then switch on the 15v to the blue wire. You could try that the other way round as well with the switch in the red wire.
Ive never measured the current drawn by my Roku but maybe other people here have some actual figures.
 
terencegbg
Posts: 4
Joined: Tue Jan 13, 2009 12:01 pm

Re: PSU Dissected for Repair

Thu Mar 10, 2011 12:28 pm

I have today tried to attached another psu, 12V and 3A and worked just fine! So I guess the amps is not enough need to buy another psu, I wonder if a 15V 1,4A will work....

Im not that good on electronics ;) dont want to buy and then discard it..... I have problems finding a small psu in able to fit in origional case in the radio with suitable specs :(

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