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slimhase
2012-09-21, 00:32
Hi Everyone, esp Logitech People;
My dear SB3 is broken:
Digital out still works, but no sound on the analog outs.
I tried all available resets (xilinx, ....) & frimware upgrades - no improvement.
I am now pretty sure that something in the box does not work properly anymore - esp that no signal comes out of the digital to analog DAC chip.
I researched all threads in here ands other sites and did some measurements, which turned out that the 3.3V needed on the DAC (PCM1748) are down to 0.9V.
But I tired cut that supply and feed the 3.3V to the DAC from another 3.3V regulator on the SB3 main board - unfortunately, w/o success.

Here is my question:
- Could anyone (Logitech People? Sean Adams?? Anyone???) share the circuit diagram - or at least a schematic - of the SB3? Or may be only the analog out portion of it?
And send it to me?
It would really be a shame, if dying SB3's can not be repeired, because the diagrams are 'vaulted'.
The SB3 is long out of production.
LOGITECH: Would it harm in any way to publicize the diagram to this dedicated community?
PLEASE?

Let me know.
Thanks, Heiner

Stratmangler
2012-09-21, 07:14
Have you turned off the analog outputs on the server?
I can't recollect exactly which setting it is, but the value 63 seems to ring a bell with me.

slimhase
2012-09-21, 07:25
Have you turned off the analog outputs on the server?
I can't recollect exactly which setting it is, but the value 63 seems to ring a bell with me.
Yep, tried that as well. Any setting between 0 (which is loudest to 63): Analog all quiet.
(Also, my other SB3 works flawlessly....)
-> It has to be a hardware issue and I need some schematic to understand what to measure where to find the issue...

Thanks for your input, though.

-> I am still in need of a circuit schematic of the SB3 (classic), esp audio part.....

Anybody?

Heiner

Atlantic
2012-09-21, 12:17
-> I am still in need of a circuit schematic of the SB3 (classic), esp audio part.....

Anybody?

Heiner

I recall seeing one, on an official/stakeholder page, either a logitech page, a slimdevices page, or a seanadams page. But I didn't download it, nor can I now find the link. I remember being slightly surprised that a circuit design was in the public domain, and assumed it was a consequence of the IPR regime under which it had first been developed.

Searching throws up a few half-useful possibilities:

http://wiki.slimdevices.com/uploads/a/ad/Logitech_Squeezebox_Boom_Audio_Design.pdf

http://homepages.tcp.co.uk/~nroberts/articleSQD.pdf

in addition to results pointing to similar questions and modifications etc on this forum, and others, including one comment from Sean Adams saying that the DAC output went to line via a 10pf (I think) cap (can you see that on the board?). The DAC pinout should be widely available, so you should find some points to do a basic test. Have you tried posting in the DIY section?

Atlantic

slimhase
2012-09-22, 00:40
I recall seeing one ...
Searching throws up a few half-useful possibilities:

http://wiki.slimdevices.com/uploads/a/ad/Logitech_Squeezebox_Boom_Audio_Design.pdf
http://homepages.tcp.co.uk/~nroberts/articleSQD.pdf

in addition ..... the DAC output went to line via a 10pf (I think) cap (can you see that on the board?). The DAC pinout should be widely available, so you should find some points to do a basic test. Have you tried posting in the DIY section?

Atlantic

Thanks, Atlantic!

So, if Logitech or Sean Adams or ... has these schematics available for the Boom, I hope, Logitech (or ...) can make them (again) available for the SB3?
Please! These things are too good to throw away!

Regarding to your circuit details:
I have the schematics from the DAC itself (from TI). That's why I measured and identified the too low voltage at the DAC power feed as a possible problem.
I also know where the 3.3V for the DAC are generated - but I don't know what happens in between - the PCB is too crowded to see where the 3.3V from the regulator go to the DAC - somewhere in between the problem seems to be.

But again: Thanks for your help & information may be, this also can be pieced together.....


So: Still my question to all ( esp LOGITECH) remains:

** Who can provide the circuit schematics of the SB3 (classic), esp audio part.....? **

Thanks, Heiner

P.S. I also posted this
- in the DIY section, but no replies there - tha's why I went 'one up' to the general discussion...
- on the Logitech forum - no feedback there so far....

slimhase
2012-09-23, 07:08
Hi;
since I am so proud, I need to let you all know:
I fixed my Squeezebox Classic!
The issue was that the 3.3V Regulator which feeds 3.3V to the DAC was broken.
I eliminated that regulator (boy are these SMD thingies tiny!) and fed the 3.3V from the main regulator on the PCB to the DAC.
This might not be the high end solution, since the DAC spec-sheet says: "It is recommended to derive the 3.3V from the 5V source for analog signal processing", but I still got it to work!
Me so happy.
(I failed in the beginning w/ the same approach as I 'cut' the 3.3V printed wire at the wrong point.... it's hard to tell IF YOU HAVE NO CIRCUIT SCHEMATICS..)

Does anybody know were one can order SMD Parts like this regulator (package label 'L33 B' -> zxcl260) where I do not need to purchase 10000 of these or pay 30 bucks shipping???

And: I am still interested, if anyone can share the circuit schematics of the SB3....

All the best,
Heiner

Julf
2012-09-23, 08:20
Does anybody know were one can order SMD Parts like this regulator (package label 'L33 B' -> zxcl260) where I do not need to purchase 10000 of these or pay 30 bucks shipping???


Depends on where in the world you live.

slimhase
2012-09-24, 00:22
Depends on where in the world you live.

Good point
:-)

I life in Germany, but I have friends in the US & UK to whom I could ship as well.

-> Does anybody have a recommendation on where to buy SMD Parts like the regulator (package label 'L33 B' -> zxcl260) online in US, UK or Germany?

Heiner

Atlantic
2012-09-24, 02:46
-> Does anybody have a recommendation on where to buy SMD Parts like the regulator (package label 'L33 B' -> zxcl260) online in US, UK or Germany?



I am out of touch with components, these days, but my first port-of-call would be here:

http://uk.rs-online.com/web/c/semiconductors/power-management-ics/dc-dc-controllers/?sort-by=default&sort-order=default

The chip ID you posted doesn't seem to come up, but this site lets you select by things such as pin count, package, etc, so maybe there's a pin for pin replacement that you could consider. Especially if the SB was designed sometime time ago.

Atlantic

bpa
2012-09-24, 04:17
Farnell ( http://uk.farnell.com/ ) sell single item of similar chips such as zxcl280. The zxcl260 is a 2.6v regulator but zxcl280 is a 2.8v regulator - you say you need 3.3v so using zxcl280 might work.

edit:
rs online also sell the zxcl280

edit 2:

according to zetex datashgeet the L33b is a zxcl330 (3.3v) which would make more sense than zxcl260 and these are available from farnell and rs (although rs only sell in packs of 10 - about 5euro).

mouser.com (in europe http://eu.mouser.com ) also sell zxcl330 in single units.

Julf
2012-09-24, 05:06
I life in Germany, but I have friends in the US & UK to whom I could ship as well.

Yes, the usual suspects are RS Components, Farnell and Conrad.