PSU Dissected for Repair

[Brewboy]

Well it's happened. My R100 is now lifeless, 20 months old - so about the right time. Haven't yet poked about inside but suspect the PSU as all externally is OK. Happened as I had to power cycle radio after it locked up and would not switch off (ie not go into standby).

Will try approaching Roku/Pinicle but suspect I will end up taking it apart and doing battle with the internal sealant. After reading the forums not sure which route to take - how is single 19V supply going - I'm worried that it will fry the display and computer side of things.

No time to look at it yet so will come back here next week.
Thanks in anticipation.

Mike

[S80_UK]

Mike - sorry to hear...

If you look around, you will see that there's a couple of chaps who will undertake repairs. In the UK, that's Pete, user ID = g0pkh, and should you not feel up to the task yourself (it is not a trivial amount of work), I am sure that he would be interested to hear from you.

[ubermick]

Mine died finally last weekend unfortunately. It's about 17 months old and I saw where Roku extended the warranty to 2 years. However after reading this thread (and since I haven't had a response to my e-mail this week), I think I might reach out to Burkhardi and get a better fix. I thought for a minute about doing my own fix (I like to tinker), but I'm more of a software guy anyway...and time-poor on top of that.

It sounds to me that having Roku replace this unit is only deferring the need to go back to Matt anyway. Any insight? Would you guys recommend going the return and replace route, or is it better to get the fix from Matt? We sure miss our tunes in the master bath!

- Mick

[molli]

Hello all,

this is now my second unit with (probably) blown up PSU each after about 1 1/2 years. Now the warranty should be gone - does any of you know of someone repairing them in Germany?

Thanks in advance for your replies,

Andreas

[dupondt]

Andreas,

in Germany there's only Pinnacle's official (and quite expensive) repair service Teleplan Repair 2000. However, Pete (forum user gopkh) in the UK will most certainly be delighted to help you. Simply contact him by sending a PM via his profile or an email to hillyp01-roku@yahoo.co.uk). He's a very experienced specialist in repairing these crappy PSUs.

Greetings
dupondt

[molli]

Thank you very much - I will contact him...

Andreas

[balthazar]

My Soundbridge Radio died recently and based on the symptoms (no display) it sounds very much like the same thing. Unit was shipped to me as a replacement for a units with the 'constant rebuffer' problem in Jan '08 and has worked really well until now. I have opened a case asking for help but no response yet.

Your post features the Electrolytic Cap which outgasses. Are the quality of this particular component and the diode the only issues or are there others in your experience?

Many thanks for a very interesting and well written post!

Update: 11/11/09
In better shape now however some observations:

The original 220uf cap obviously got VERY hot. The yellow goo was discolored. I also found a 2200Uf cap behind this one also showed signs of stress. Everything is up and running using parts from my home stash but the 220 Uf cap is running warm (not too hot to touch but hotter than a non resistive device should be).

I did some research and found that caps used in today's switched power supplies shoud be of the low Effective Series Resistance (ESR) types. If not they can overheat, cause inefficient operation and fail prematurely.

I have ordered Caps specified for use in these specific applications from Digikey once they arrive I will try and compare performance. I wonder frankly if this is the issue wth the original caps? Not the right type for these high frequency switch mode power supply apps. If so my prospect for a lasting solution with the built in supply may be good.

Update 11/19/09
Panasonic caps and replacement Schottky arrived from digikey and I rebuilt the unit. All has been well for about a week now so I am cautiously optimistic. Sound seems as good as before including bass. I will try to report back when and if anything changes.

[Fixma]

Here in Europe we have Conrad and they have a nice replacement PSU.
http://www.conrad-uk.com/goto.php?artikel=511293
15v and 0,8 Amp for 25,91 EUR and it fit easy inside the R1000 (lxbxh) 57 x 70 x 25.3 mm)


Here the data sheet: http://www2.produktinfo.conrad.com/date ... _800MA.pdf

Or if you go external, but you can place it also inside!: http://www.conrad.nl/goto.php?artikel=511180
15v and 1,6 Amp for 13,99 EUR. But you can place it also inside!




I think it is perfect for the R1000!

[spiffy_chimp]

It's been quite a while since I stopped back here at the Roku cocktail lounge, and I'm seriously impressed at what you folks have been able to do with that power supply. For myself, I finally did a complete rebuild using all new components but the original PCBs. I upgraded all of the caps to high-temperature models as well as beefing up the current limits on the inductors. There hasn't been a single glitch since that time.

For those PSU buffs out there, I was very impressed with that TOP247 part. So much so, that I've been using it and similar switchers from Power Integrations in many PSU designs. For anyone who finds themselves needing low-current DC from mains voltage, their Linkswitch-TN models are fantastic. Half a dozen components and you get nicely regulated DC power. It's even possible to do non-isolated designs with no transformer.

On some moral level, I tend to believe that a SMPS is just wrong for audio electronics, especially powering an amp. That might just be my own pet peeve. On the other hand, it would be tough to justify an enormous toroidal transformer inside a small case like this.

I've moved on to other projects, but my Roku radio is always playing there in the lab while I solder away at something.

[alanmc]

@ spiffy_chimp

Having also owned a couple of the very fine Reciva based Roberts WM-201 radios which have been left in use/standby for nearly 2 years without problems or indeed any signs of overheating due to what I can best describe as them having a very conventional power supply with a large built-in mains transformer and “well-ratedâ€

[S80_UK]

.... and on inspection you instantly find the cause is that they are built with components that are IMO not only poorly rated, but are also closely crammed together, thus overheating.

Hey Alan, I always thought you had led a sheltered life... now you seem to be going all technical

But you are completely right. A big problem is that in compact power supplies (and some others) poor layout leads to components like electrolytic capacitors being placed in close proximity to power resistors or heatsinks. The electrolyte slowly dries out and the capacitor gradually loses capacitance. It is this partial decay that results in power supplies often hanging on until a unit has been shut down for a while. The power supply can handle the steady state current, but not the increased current associated with starting up.

(All this is known and previously discussed, but I felt it helpful to re-iterate in view of the posts from spiffy_chimp and your good self.)

Cheers,

Les.

[alanmc]

Hey Alan, I always thought you had led a sheltered life... now you seem to be going all technical

Les, you give an old pensioner like me far too much credit by even suggesting that I seem to be going all technical. My abilities with a soldering-iron and some araldite are very much limited to occasionally building a project that "someone" else with the necessary technical knowledge has been so kind as to forward their proven circuit-design to me. I think I know my limitations . . . . but still love to dabble

[geekguy]

I too had 2 dead R1000 Soundbridge Radios. They died within 8 months of each other and each was about 18 months old.

Roku replaced the first one, but Roku was silent when I tried to contact them to request a replacement for the second one. Having nothing to lose, I decided to follow the excellent advice in this forum.

I decided that I would try to replace the original parts as my Plan A. My Plan B was to use an external transformer power supply with a voltage regulator to get the 19V and 9.5V outputs. I'm happy to report that my Plan A worked.

I replaced the following parts (showing the Digikey.com part numbers):

641-1414-1-ND DIODE SCHOTTKY 2A 60V DO-15 (replaced 1)
493-1578-ND CAPACITOR 220UF 35V ELECT HE RADIAL (replaced 1)
493-1597-ND CAPACITOR 2200UF 35V ELECT HE RADIAL (replaced 2)

A Radio Shack de-soldering iron was very useful for removal of the old solder. Patience is indeed a virtue since the inside of the unit is truly a mess of glue.

My skill level is pretty basic and it took me a while to perform the fix, but I'm delighted with the results.

Thanks to all of you for your expert guidance! I could never have done it without it.

I had so much fun fixing it, if anyone is fed up and just wants to wash their hands of Roku, I am looking to purchase dead R1000 Radios.

[g0pkh]

Hi there

Well done on the fix, its not so bad, is it ?

However I would suggest that ALL the electrolytics should be replaced.
Also upgrade the diode to a 3A 60V device.

They are such a "pig" to get into it would be a shame to have to do it again very soon.

Regards

Pete

[billd]

My original repair (replaced burnt-out capacitor with a higher temperature part) failed agan after 12 months - this time many components burnt out.
So I tried the external power supply solution discussed here. Well, that was great advice because it worked well.

For your information, I have posted a parts list, LM317 reference curcuit, and photos of my repair here:
http://www.tvxb.com/doc/Roku%20PS%20Replacement%20Instructions.htm

I'm using a 13V plug pack and can't detect any difference in volume or performance running the amplifier at 13V or 15V vs. 18V.
My LM317 circuit is supplying 9.8V to the system unit.

The LM317 casing sits at 90C using an 18V supply. At 13V it sits at 60C. So for this reason I suggest 13V or 15V supply is preferred for this configuration.