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Saturday 5 September 2020

Bush NE-2105 DAB Clock Radio repair.

 Mrs Doz stuck her head round the workshop door...

"The kitchen radio's stopped working. It's just making rude noises."

I went to inspect it ...

Sure enough it's just sat there, with it's LCD display flickering and making raspberry noises..
It's a Bush NE-2015 DAB radio with FM and a now long-obsolete iPod dock. It's put in Sterling service for 9 years...


Anyway... let's get it apart. Bush (or whoever makes their stuff these days) have carefully marked the fixings I need to remove with an arrow ... it's almost like they want someone to repair it...


Four screws on the bottom along the front....













... and two on the back, hidden under a plastic cap which just pops out...

There's a knot in the aerial wire, undo it...










Slide the back off, and undo the mains, auxiliary input connectors, and put the back to one side...











 It all looks rather nicely made. I'm pleasantly surprised.












Even if they didn't *quite* manage to get the switched mode supply IC in straight!

There's no sign of capacitors having blown their tops, no leakage...








5 Screws sees the main PCB lifted so I can gain a bit of access..










There's some signs of that nasty glue, that turns brown and goes conductive... it's scraped off before it gets worse.



Now a hunch tells me the power supply isn't starting up. The supply is started up in the usual manner, by a voltage fed from the mains rectified voltage, via a resistor chain, and a small capacitor. I check the (two) mains reservoir capacitors are dischanged with a 10K resistor (and they were holding a charge, enough to give the unwary engineer an unpleasant zap!) . The small start-up supply capacitor is removed. It's 47uF at 25V... 

 The ever-reliable Jingyan MESR-100 ESR meter shows an ESR of 6.67 ohms... 











A new one measures 0.34 Ohms, much better..












I also check the two main reservoir capacitors... They're 10uF at 400V each...

ESR is acceptable.









As is the measured capacitance. I'll pronounce those fit, and re-fit them, along with the new start-up capacitor...










A quick re-assemble, and, ace ... it all works!


Another saved from land-fill. I'm always surprised by the audio quality from this little radio, and now I'm impressed by it's build-quality too... a rare thing in this day and age. Well done Bush!

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