One of my friends rang me recently with a question.                     Did I want a free DVD player?
I didn’t hesitate to say yes….      I can never resist a “free bee”!
There was a catch however.       The DVD player would turn itself off after about 5 minutes.
Well,  I should be able to sort that out…  No worries!….  (surely?)
They just got a new recording DVD player so they didn’t want the old player anymore.
“If you can get it to work, it’s yours!”

The next time we visited,   a large box was offered to me.
It contained the offending DVD player,,  and also a VCR.
They also had all the manuals and remotes for these units,  and all in pristine condition!
They were both Sony units and the DVD player would have been top of the line when new.
The VCR was a HiFi model too,   worth fixing I thought.
There was also a little red race car!…      A little red race car?       Well yes!      It was a video tape re-winder!

I was told exactly what was wrong with these units :

    The DVD would start to play a movie and would then stop and go into stand-by mode.
    A great deal of money had already been spent on this unit in the past.
    Apparently the whole laser assembly had been replaced.
    They were pretty cheesed off with it by now and decided to rid themselves of it!
    The VCR was “worn out” and "chews tapes"!

When I got home, I lost no time in hooking up the DVD player to see what it did.
This would have to be the most elaborate DVD player I had ever seen!
It boasted 2 sets of stereo sound outputs, plus a 5.1 channel set of outputs as well.
I set it up to play a DVD and waited.
Sure enough,  after 8 minutes…               Everything stopped and it was in stand-by mode again.
Well that WAS really annoying!

Sony seemed to have a slightly different way of doing things.
The power switch does not turn the whole thing off or on.
Instead,  it turns the whole thing off or turns it into standby mode.
To then play a DVD one has to either turn it on with the remote, or press the open / close button on the unit.
The power switch seemed a mite “dicky” for want of a better word!
I decided that I would investigate it.

I was thinking along the lines of some weird reset problem or some mechanical problem that would shut the unit down....                                                                   Time to open the beast!
I was greeted with the usual array of circuitry.               I decided to tackle the power switch problem first.
The whole power supply was reasonably easy to remove and examine.
Quite often the power up reset function is part of these switch mode supplies so,
a good “once over” was in order here.
This power switch was a little odd compared to the usual arrangement.

As expected, the main part of the switch was a standard double pole unit that switched the mains active and neutral.
The odd bit however was a little auxiliary switch hanging off the back of the main switch unit.
I’d never seen anything like this before!                          I checked the Mains switch contacts with the meter.
They seemed to be fine and measured as close to zero ohms as I could wish.
The switch also seemed to be mechanically sound too.      
But what of the little switch hanging off the end?….                  Different story here!
It measured a few ohms one second, and then the resistance went all over the place!
Operating the switch button revealed it to be very unreliable.

This was undoubtedly the source of the “dicky” switching I had observed originally.
I traced the connections to this switch and found that it controlled part of the switch mode supply.
Could this be the reason the unit turned itself off?
I was hoping (but not really expecting) it to be this easy!          Well that switch had to come out!
Once free of the circuit board,  the little switch easily separated from the main switch.
Curious to find out what was wrong with it,     I dismantled it.

There seemed to be a thin film of “gunk” on the fixed contact.
I decided that a wash in Methylated Spirits was in order!              Alcohol would not harm it.     (I hoped!)
When it dried out and was re-assembled, it behaved like a proper switch once more!
I then installed both switches back onto the circuit board.
I checked the contact resistance again and was pleased to find it was very low and stable.

I then gave the rest of the board a check but could not find any other problems with it.
The DVD player was then put back together and worked perfectly!            
That was the only thing wrong with it!
The whole exercise took about 15 minutes from start to finish.

Now the VCR that went with it!
One look at the transport mechanism was enough to put me on the right track!              It was filthy!
Also,  the grease on the tracks for the loading arms was dried up.
The Video heads also looked grotty,  as did the rest of the heads.
I gave the whole lot a good clean up.                  
I then loaded a tape and checked all of the functions…            Perfect!
So the “worn out” VCR was back in action!

The units are now set up in the bedroom so we can watch movies in bed on those cold winter nights.
The next time I saw my friends I told them that I had fixed the problems with the DVD and VCR players.
They still didn’t want them!                   (I felt a bit guilty about how easy they were to fix).
They then offered me a Sony Play-Station that they didn’t want anymore….
But that will have to wait until another time!