SB3 almost dead..

[arfond]

One of my wireless SB3's has decided to nearly die after a few years of service. When I switch on the power the screen is working for anything from half a second to almost a minute. It seems the longer I leave the power off, the longer the screen stays on before it goes off. I've tried / tested the following:

- factory reset using "add"
- xilinks reset using "1"
- measured power supply voltage (measures 5V)
- tried a power supply from my other SB3 (measured at 5V too)
- removed the wireless card

I'm running SqueezeCentre from a DS209+II Synology NAS, version 7.5.0 (the Synology version). The SB3 in question and my other SB3 and SB Radio were all working fine. I also switched back to Squeeze Box Servier 7.5.1 running off the PC to eliminate the NAS from the equation, but nothing. The other SB3 and SB Radio are still working fine off the NAS.

My working SB3 has firmware 130, the almost dead one probably has the same.

Any suggestions / advice?

Thanks in advance and sorry for the long post....

[tedfroop]

Power Supply

Is it in or out of warranty?

[arfond]

Hi, it's out of warranty - had it for three years or so

[sander]

It could just be the wifi card. If its optional, I'd try removing that first.

[peterw]

It could just be the wifi card. If its optional, I'd try removing that first.

arfond says he already tried that. :-(

[TiredLegs]

Is this just an issue with the display screen going blank, or does the whole unit turn off? Or, to look at it another way, does the SB3 keep playing music when this happens?

[arfond]

Don't think it's the screen

Hi, I haven't been able to get the screen to stay on long enough to play and music. What I do know is that it after the screen has gone off it is not appearing as an available player on the web interface. Based on this, I don't think it's the screen. Any other ideas?

[ghostrider]

Power supply?

[Adam_F]

Your issue seems similar to one I had with a SB3 a while ago. What I would suggest is measuring the internal supply voltages (particularly the 1.2V supply at L4) as described in the thread below and posting the results here:

http://forums.slimdevices.com/showthread.php?t=74844

[arfond]

Thanks Adam_F, I'll give this a try. I followed the links and I couldn't see a conclusion to your problem... Did you get it fixed in the end? I'll post my measurements here and on the other post in a few days. Thanks.

[arfond]

Here are my measurements.....

Here are my measurements (first line are from mfieger in this post - http://forums.slimdevices.com/showthread.php?t=74844 - then mine below):

MFIEGER : 5V in the circular via next to the large capacitors.

Mine : 5.12V

MFIEGER : 3.3V on the metal tab of the voltage regulator U18.

Mine : 3.29V

MFIEGER : 1.2V on the C49 side of the inductor L4.

Mine : 11.9mV (yes, mV)

MFIEGER : 14.8V in the via next to the right side of the ceramic cap.

Mine : 14.35V

MFIEGER : 56V anode supply for the VFD, right side of R51.

Mine : 55.8V

Looks like L4...

[Adam_F]

It looks as if the problem is with the 1.2V supply to the SB3's CPU (the part marked IP3023 on the duaghter board under the wireless card). The problem I had was also with the 1.2V supply, but I am not sure if the cause is the same yet.

As far as I can determine, the 1.2V supply is generated from the 5V line by U17 (switch mode regulator chip) in conjuntion with Q3 (FET), and then fed to the CPU via L4. If you have a look at page 5 of the datasheet for U17, you can see roughly what we are dealing with:

http://www.chipsinfo.com/NJR/NJU7630.htm

We need to narrow down the problem a little further - would you be able to measure the voltage at each leg of Q3 ?

If at all possible, let everything cool down and measure the voltages again before the display goes blank.

[arfond]

Q3 measurements

Here are my measurements at Q3 when the screen is on.

Left side (L4 side) - 2.71V
Middle - 1.18V
Right side - 4.61V

I also measure 1.2V at C49 side of the inductor L4 when the screen is on.

When the screen goes off:

Left side (L4 side) - 5.11V
Middle - 0V
Right side - 5.11V

11.9mV at C49 side of the inductor L4 when the screen is on.

[Adam_F]

The issue is that the 1.2V supply to the CPU is shutting down soon after power on. Judging by the measurements you took the most likely causes in my view would be:

1) A hairline crack in a solder joint in the circuit around U17 and Q3, which opens up when things start to warm up. It would be worth examining the circuit board in this area with a magnifying glass to see if there is anything obvious.

2) Either Q3 or U17 is failing. If this is the case, unless you have access to the correct spare parts and are experienced with surface mounted components, it is not going to be easy to repair back into its original state unfortunately.

Have you contacted Logitech to ask whether they can still repair SB3s ? If as I suspect the answer is no, I could suggest a 'quick and dirty' method of restoring the 1.2V supply to the CPU if you are handy with a soldering iron. Not entirely satisfactory as a repair, but you might want to give it a try if the only other option is binning the SB3.

[arfond]

Thanks Adam_F. Had a look and couldn't see a crack in the line. No repair from logitech either. So, before the bin, I'm willing to give anything a shot. Can you spare the time and send me the quick and dirty fix for the CPU supply? Thanks in advance.