Yamaha YSP CU3300 power problem

Hi All,

I aquired a non working TSP CU3300 soundbar. When you power it up with the remote, it briefly flashes on the display of the soundbar, then powers off after 1-2 seconds. Plenty of other threads on here about chnaging capacitors on other YSP models, but nothing on the CU3300 i can see.

Have a look at the attached picture, based on the physical location, i am wondering if the caps CB3 (blue circle) and/or C4 (red circle) are the ones i should try replacing first? These are both 0.22 uF 275V caps - the other threads on other models of YSP were 0.022 uF caps, so an order of magnitude difference, but i was thinking more about their physical location on the board


Should i look at replacing C20 and C21 which are the 2 brown ploy caps just below and left of the red circle. These appear to be 2 x 0.022 uF caps as they are marked 223K. I have one of these on hand, but not 2 at the moment.


Any advice greatly appreciated!
Bump - any ideas?

I replaced the circled caps as well as c20 and c21, and its still dropping out. As soon as you power it on with the remote, it lasts for about 1 - 2 seconds then turns off
OK, Have made some progress. I managed to find the service manual and boot the unit in 'no protection'mode - so i understand this means even if there is over or under voltage, it still boots.

And it did this, passes most tests although it states the following errors/issues

Power supply tests - Airwired on - fails this test
- FL on - fails this test (no idea what FL is?)

In the voltage tests, it states the airwired voltage is 000, should be between 102-137

Then in the test that shows where the unit has powered off historically due to protection of under/over voltage it shows both airwired and analogue power supply voltages have been under spec and are the reason for the power down.

So don't know if this helps or not, but any advice appreciated! I'm still leaning towards a power supply board/capacitor issue, but happy to do any suggested tests - particualrly now i can power the unit in this mode. I can actually connect my phone via analugue RCA cables and get sound out of it (low volume), however setup menu functions don't work in this mode
Think i have made some more progress, but really would like some input as to where to go from here.

There is no 6.3V being generatedm, and this supplies the airwired module, which is what error is showing, so i think this is my issue. Have got down to this section of the schematic.

No voltage at L11 or L5. D14 which is in the 3.3V line has 3.3v. There is no C24 installed (its an australian model, and only some countries have this component installed). I can't really work out where to backtrack now, don't understand what/where is S1,S2,S3 etc.

Also not sure if C80 (top left of diagram) would have anything to do with the issue - tis a surface mount cap on the rear of the board



Novice Member
I've found the service manual , but impossible to start the Self-Diagnostic Function ,using normal or protection cancel mode .
Each time i start the initial setting mode ...
I have a european model .
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Progressed a little, found i was in fact getting correct voltage in the diagram above, and am getting both 5V and 3.3V at the airwired board. However in the diagnostic, it states the airwired is undervoltage at 000.

When i power up the sub, the green LED does not light, however there is power at the sub board. Not sure if this is related or not?

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