Another Soundbridge Radio Dead

[regnault]

Hi!

My Roku is dead too
http://forums.rokulabs.com/viewtopic.php?t=19396

Support asks to send it back for replacing. But I live in Russia and post service will be cost too much, more than Radio itself.
I've tested voltage


No Load:-
+9.18V
+18.87V
With load (plugged into front unit)
+5.45 - 5.55
+18.87


What radioelement should I replace ?

Sounds like the same problem I just had; have a look at this photo and others in the same set:

http://www.flickr.com/photos/aaronferru ... 593223550/

Be warned that opening up the R1000 for a power supply repair is not a trivial task!

Like almost everybody else my Soundbridge died a couple of weeks ago after 13 months of opertion. Althought I haven't done a lot of electronic repairs for 20+years (used to repair radio/TV to pay my way through college) I decided to fix it myself. I followed the guide set out by others on this forum and back up the comments that dismantling the PSU takes a LOT of care and patience. Also when you have the PSU apart TAKE CARE as there are parts of the unit that are live to 240V mains.
However when you have got the PSU board exposed the repair is relatively trivial. I replaced the 220uF 35V capacitor as per the flickr picture above and the radio did spring back into life.
However; when off load the PSU voltages were unstable, ~10.5 and 22v.
On advice from Pete G0KPH I then checked all of the other electrolytic capacitors on the board. Most were within spec although all on the low side but the small 47uF 16v cap in the HV part of the PSU had reduced to 27uF. ie heading for failure Replacing this cap brought the O/P voltages back down and far more stable. As the high running temerature and continous operation of this PSU will have used up most of the lifetime of all electrolytic capacitors I replaced them all with 105C low ESR units. I also replaced the 75R resistor with a higher wattage unit.
Incidently my 9.5V rail still measures 9.55v off load and 9.1V under load.
So thank you Pete and everbody else who has provided helpful information on this forum.
As a professional engineer with many years experience I consider that the Soundbridge radio is a unit where the power supply is bound to fail on a regular basis. Because of the total lack of thermal management which is mainly due to the plastic box and tape around the box the components on the PSU, which is always on, run at an excessive temperature. Back of the envelope calculations suggest the mean time to failure will be in the order of 7 months! Even with the higher rated replacements I have only improved this figure by about a factor of three.
Great gadget, fantastic sound quality but CRAP engineering.

[Technew]

My Soundbridge radio died today, AGAIN! Managed to replace the faulty cap, to a 220uF/63V, in May last year. and it has worked well since then. Have now disabled the unit and find that the output voltages are wrong. With no load I get 5.3VDC on the 19VDC output and 2,7VDC on the 9.5VDC output.
Any ideas what component(s) to replace?

[DJans]

Technew, if my Soundbridge Radio PSU will die in that way that replacing the defective cap will not bring it back to life, I will replace the complete PSU by a 19V notebook PSU and add a 7809 for the 9.5V.

Maybe that is an option for you.

[Technew]

DJans, thanks for your reply.
I found this last night: http://forums.rokulabs.com/viewtopic.ph ... 7&start=15
So I removed the internal PSU and connected an external switching 12V/2A PSU and now the Soundbridge Radio plays again!
Kept it swiched on over night and still working this morning. Hope it stays that way.

[Burkhardi]

DJans, thanks for your reply.
I found this last night: http://forums.rokulabs.com/viewtopic.ph ... 7&start=15
So I removed the internal PSU and connected an external switching 12V/2A PSU and now the Soundbridge Radio plays again!
Kept it swiched on over night and still working this morning. Hope it stays that way.

Good job TechNew,
Keep in mind, that your power output from your three amplifiers will not be as much. It will play fine, it will also be robust, but it will just not be/play as loud (which may be fine for your needs) just wanted to note this for anyone tagging along this thread)). Let me PM you and see what you did (12v supply in or out), I may have some ideas to help with sound quailty since you may have removed the OEM supply and changed the airspace. I have a spare unit here that I built up on a 12v wall-wart for testing and it sounds just the same and works fine. Only caveats are the on board regualtor runs hotter on the main board of the unit since it's having to convert 12v and not 9v to the proper voltage and the unit plays softer. I still have not got solid numbers yet (and is one reason I built it) to tell you how much softer it plays, but I plan to get that sorted out one day soon. Djans idea will work too (I much prefer it), but I would watch the airspace issue for the woofer enclosure either way.

Just my 2-cents worth, Matt

[Technew]

I have now tested with an external 19V PSU and a 9V reg. Can´t hear any major improvement regarding the "power" of the sound compared to the 12V alternative. Also installed the 9V reg externally and noticed that it got very hot, taking down the voltage from 19 to 9V. And hotter it will get installed in a totally closed environment.
So I have gone back to the ext 12V. The bass sound gets a bit softer but more clear, I think.

[batigol]

Hi All,

It has been very interesting reading this thread. It sometimes feels like I am in an electronic engineering tutorial!

Some of you may have seen (on another thread) that I had an issue with my Soundbridge which I sent to Germany yesterday to be fixed/replaced. I will see what happens on that front.......but as an aside, assuming I do receive a working radio back my question is this:

Would I potentially increase the life of the radio by disconnecting it from the mains each evening or does it make no difference to leaving it on standby 24/7?

Thanks,
Ben

[alanmc]

The R1000 was conceptually designed to be constantly powered ‘on’ . . . . any such “radiosâ€

[jjaf]

If your R1000 is sited in the kitchen, a traditionally damp environment, then keeping the components in a permanently heated state may reduce the damaging effects of water vapour on electronic components. Just a thought, I have no technical expertise to back up that claim.

[Technew]

Another advantage with external 12V to the SB is that I can bring it out to the garden in summer and use a battery to run it. Just bought one, a small Sealed Lead-Acid Battery 12V/10A and a 0.8A charger. Total cost approx. 33 EUR. Fully charged it will last for at least 15 hours use (SB takes less than 0.6A). Have now run the SB cont. for about 10 hours and still running great.