2006 Sony mini boombox no power

[Richard9025]

Hi ! My friend gave me this radio for repair, it is a Sony CFD-S03CP.

It was working as a kitchen radio for ~5 years and one week ago it just stopped. The power button does nothing when plugged into the wall socket or on batteries.
My first guess was the power supply, but I checked the voltages in the power supply and they were all okay, the power is getting in the radio.
The inside is very clean, no cracked traces or pads, it was sitting all the time, not used like a portable unit. No bulged capacitors or other components that look defective. Now it is all disassembled and I can easily get to a bad component. I have a soldering station and a hot air gun, but I don't have an oscilloscope or other instruments except the multimeter for checking things.
So, what should I do now, as first steps in repairing this "new" radio?
Thanks !
Service manual: http://archivos.diagramas.mx/otros/CFD-S03CP.pdf
Images coming soon.

 

[shrtrnd]

My daughter had me look at one of those. Her problem was the switch assembly itself.
You might check that, just to be sure it's actually 'switching'.
Next thing I'd do is what you've probably already done. Look carefully for any physical damage to components.
Darned plastic parts often break-off. Check to make sure all those doors don't have interlocks that aren't being
activated by a broken-off (or broken and stuck inside the hole) plastic prong (that might be keeping the box from powering-up).
Before I went into troubleshooting the electronics, I'd make a quick check of all the push-buttons to make sure they
actually make electrical contact when depressed, and that one of them isn't stuck, causing the problem.
I'll mention that being in the kitchen, it's been subjected to humidity. I'd look carefully at all of the electrical contacts just to be sure none of them are corroded from moisture.
(That oughtta keep you busy for a while, and you may actually find the problem)

 

[shrtrnd]

I ASSUME that one of the first things you checked, was the fuse?

 

[Richard9025]

You might check that, just to be sure it's actually 'switching'.

I checked if the power switch works and it surely does (checked with continuity when it's pressed)

I ASSUME that one of the first things you checked, was the fuse?

Of course, the fuse isnt blown and I checked the parts and they all look perfect.
Sorry for the late post.

 

[Richard9025]

Any suggestions? Maybe some voltage checks based on the service manual? Thanks!

 

[shrtrnd]

It sounds like you probably already have, but with the unit disassembled, I'd just carefully visually inspect the electronics to try to determine any components or circuit trace that may have burned open-circuit.
Frankly, the 'voltage checks' you asked about seem pretty obvious to me.
Start at the input power, through the power on-off switch, and keep tracing that power input path until it stops.
That's where your power interrupt is happening.

 

[Richard9025]

Found the problem, a jumper was poorly connected, reconnected it and now it works flawlessly

 

[shrtrnd]

Congratulations. I'm sure the owner will be pleased that you could help them with this.
Something to bear in mind when you offer to help somebody out with repairs; they often won't admit when they
made some mistake. (Not saying this was the case here). I just wanted you aware of the fact that my experience is that somebody accidentally drops the electronics, or spills some liquid on it, and won't tell you that when they ask you to look at their problem. When I get something somebody asks me to check, I almost always open it up, just to look for obvious problems before I try to turn it on. Good luck with any future repairs you try, almost nobody anymore has simple common sense troubleshooting skills when it comes to trying to fix their own equipment.