Broken DVD Player

Here's a case of premature component failure in a Pacific DVD Player model 1002Mk2.

Pacific is a brand sold exclusively in the UK by the Asda supermarket chain.  The electronics seem quite well made, and this model has had very good reviews.  This particular player was bought new circa 2007.  It suffered a power fault about 3 years ago, which was traced to a 1000uF electrolytic capacitor on the main power rail.  That was replaced at a cost of about £0.20 - no other components appeared faulty at that time.

The player came back to me a couple of weeks ago with similar symptoms - on power-up, the standby LED would light, but it wouldn't do anything else.  Once on the workbench I powered it up to observe symptoms for myself - sometimes users don't always notice everything!  However, on pressing the standby button, the display flickered into life and the drive started spinning up.  After just two seconds, there was a loud bang, a small flash from inside the front right corner and everything died.  Life-expired then?

Being of enquiring mind, I unplugged the player from the mains supply and took a look inside.  Close inspection revealed two things: a violently blown fuse (unsurprising) and a bulging electrolytic capacitor, colloquially known as a 'bad cap' or capacitor plague.  Once the circuit board (marked M479) was taken out, it was apparent that the power supply control IC had lost its markings.  Here's a close-up:

The top of the chip was eventually found inside the front panel of the player!  The sides of pins 1 and 2 are burned or melted, as though they arced or shorted together.  Once the chip was removed, further investigation revealed two short-circuit diodes forming half of the input bridge rectifier which in turn fed the bulging cap, the control IC and the transformer primary.  The bad 22uF cap was removed; it tested very low capacitance.  Here's the damage:

The likely sequence of events was:

1. Over time, the bad cap lost its ability to smooth the rectified supply, producing more supply ripple and higher-than normal peak voltages
2. The control IC detected over-voltage and/or current and shut down as it was designed to do.  This was when the user reported the fault.
3. Re-application of power after a few days produced an over-voltage spike that the control IC couldn't sustain - un-smoothed DC has a much higher peak voltage.
4. The high voltage blew the FET in the control chip going short-circuit which then blew the two diodes that happened to be on their conducting half-cycle - and then the fuse blew.

Which brings us to the $64,000 question: is it worth repairing?

As ever, it's all down to cost.  A new player would be about £30, so if the parts cost less than this then maybe.  But we don't know whether the power surge damaged anything else; all the MPEG and DVD control chips might be fried.

Initial web-sourced parts pricing is around £8.50, so it's probably worth a shot.  Watch out for an update after the parts arrive and repairs attempted!