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AWA DVD player not operating...

Numnut

Apr 3, 2013
2
Joined
Apr 3, 2013
Messages
2
Gday All,

Ok, I know this is for a cheep end DVD player. And I can replace it for around $60 AUD. But as I am currently undertaking an electrical apprenticeship, I thought what the hell and give it a go.

This has been sitting on the shelf broken for a couple of months now so thought better to practice then through it out.

On inspection this unit would not turn on so off with the case and first thing I see is a blown Cap that has dropped its guts over a resistor and a diode for the rectifier circuit. The Cap was a 22 uf 400 V unit. All I could get to replace it is a 22 uf 450V one. A new Cap, resistor and diode fitted. I checked the out put on the power rail. Where I should be getting (as printed on the card) is

G_+5_G_+5_+12_ G_-12.

What I am reading is

G_-1.96_G_-1.96_+12.42_G_-16.34

I take it there is still a problem with the power board. and the unit is obviously still dead.

Now, I might get a blast for this, but any pointers on were I could go from here would be appreciated. Do I need to look at other components on the PB or could it be related to a fault on the process board?

Thanks in advance for any and all reply's.
 

shrtrnd

Jan 15, 2010
3,876
Joined
Jan 15, 2010
Messages
3,876
The cap probably blew because one of your voltage regulators went out.
You're in the right area (power supply), you just need to identify the part that
failed that caused your cap to blow. A 22ufd at 450V will work just fine.
From your readings, I'd be looking at the 5V regulator first.
Good luck.
 

sheldonstv

Jul 17, 2007
68
Joined
Jul 17, 2007
Messages
68
give me the model and ill look the service manual up for you-smps power supplies are not very forgiving if serviced the wrong way-also-no connecting ANY SCOPES up to monitor supply rails without using an isolation transformer or there will be a loud bang and lots of magic smoke
 

Numnut

Apr 3, 2013
2
Joined
Apr 3, 2013
Messages
2
give me the model and ill look the service manual up for you-smps power supplies are not very forgiving if serviced the wrong way-also-no connecting ANY SCOPES up to monitor supply rails without using an isolation transformer or there will be a loud bang and lots of magic smoke

Thanks for that Sheldonstv, Its an AWA DP 239. I have tried to locate a systematic on line with no luck so was going to map out the circuit to see if I could note it out that way by calculating the values. Will wait to see if you have any luck to save me a bit of head scratching lol...

Appreciate your help.
 
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