dynex hdtv/emerson hdtv troubleshooting

[ddarn]

I recently had an electrical storm come through my area here and lightning ended up frying 3 of my hdtvs.. 2 of them dont have any power at all when I try to turn them on(Dynex 32 in hdtv & Emerson 32 in hdtv) . My buddy troubleshot it some and he had said that the power boards in the tv look ok and he thinks I should swap out the main boards.Before I do this though I was going to ask here.It would seem to me though that if I have absolutely no power at all(including no standby light) that the card that would be bad would be the power board but I'm not an expert on this as it is my first foray into tv repair.One other thing:I do have reason to believe that the surge could have come through my satellite line to the hdmi cable,but I also had a circuit breaker tripped in my house circuit box so I dont know for sure.Any help is appreciated..thanks

Ps--model nos..Dynex Dx-32L220A12, Emerson LC320EMZ

[ivoh]

Re: dynex hdtv/emerson hdtv troubleshooting

check smd fuses on mainboards. check for stdby power. dont be so quick to throw parts at it.

[budm]

Re: dynex hdtv/emerson hdtv troubleshooting

Do you have Digital Volt-Ohm meter? You need to at least check the main fuse, if it is OK, then you need to see if you do have any DC voltage at the two legs of the main filter cap in the primary side of the circuits.

[ddarn]

Re: dynex hdtv/emerson hdtv troubleshooting

I checked the main fuse on the power board..they were good..where would I locate the fuses on the main board..keep in mind,I'm a newbie to tv troubleshooting and yes I do have a meter..thanks..

[budm]

Re: dynex hdtv/emerson hdtv troubleshooting

I think to make it less confusion as to which one of the two TVs we are trying to fix. Start new post for each one of these two TVs and also upload good clear pictures of the back of the TV and all the boards.
You need to find out if you do have DC voltage at the two legs of the main (primary side) filter cap or not.

[ddarn]

Re: dynex hdtv/emerson hdtv troubleshooting

I wanted to start on the dynex first...I will be uploading the pics of the main board and the power board..as of checking for the dc voltage at the two legs of the primary side,where would I check for that? Like I said I am new to that,and I was going to just swap out the bad card.

[ddarn]

Re: dynex hdtv/emerson hdtv troubleshooting

forgot the pic of the back of the power board..

[martino]

Re: dynex hdtv/emerson hdtv troubleshooting

I circled the legs of the main cap...
Put digital voltmeter on DC scale,highest setting.measure from one leg to the other.
CAREFULL!!!! Don't slip,high voltage there....
What voltage do you get there?
P.S. This cap can keep a charge,so don't touch legs even when powered off,it hurts...

[ddarn]

Re: dynex hdtv/emerson hdtv troubleshooting

0 v ..the 2 cards have been out of the tv for quite a while now(about 2-3 wks)

[martino]

Re: dynex hdtv/emerson hdtv troubleshooting

the powersupply will have to be plugged in,in order to do this test.

[ddarn]

Re: dynex hdtv/emerson hdtv troubleshooting

I plugged it in and I get 1 using the 200M and 2000m settings and 17.71 on the 20 setting..I dont know how good the digital meter is (its on old meter I got from my father in law) and my analog meter I used completely pegs to the right on the highest setting when I measure it so...

[ddarn]

Re: dynex hdtv/emerson hdtv troubleshooting

I got a good fluke from my father in law and the reading was 161.2 and it had the letters " Loz" near the bottom whatever that means...Its been over 20 years since I troubleshot anything so I guess I need to take a refresher course..lol

[ddarn]

Re: dynex hdtv/emerson hdtv troubleshooting

reading sound good?..if so,what next?

[martino]

Re: dynex hdtv/emerson hdtv troubleshooting

161.2 volts with the fluke meter? Ok,stick with the fluke I'd say
On the 13 pin connector,pin 3 is 5vstb? or pin 4,I cant read the print clear..
what do you read there? measure between pin 3(or 4) and pin 6(GND) with meter on 20 volt DC..

[ddarn]

Re: dynex hdtv/emerson hdtv troubleshooting

yes its pin 3...measuring 0 L...infinity..its even hard to see it over here..Im going blind.

[martino]

Re: dynex hdtv/emerson hdtv troubleshooting

Can you read whats printed on N501? (see pic,I circled it)

[budm]

Re: dynex hdtv/emerson hdtv troubleshooting

yes its pin 3...measuring 0 L...infinity..its even hard to see it over here..Im going blind.

Is that in Ohm or Volt? Otherwise turn the Volt up to higher scale, also you using chassis as the GND ref.?

[ddarn]

Re: dynex hdtv/emerson hdtv troubleshooting

can you read whats printed on n501? (see pic,i circled it)

a6059h sk172 14139d

[ddarn]

Re: dynex hdtv/emerson hdtv troubleshooting

Is that in Ohm or Volt? Otherwise turn the Volt up to higher scale, also you using chassis as the GND ref.?

I measured pin 3 which was 5vsb to pin 6 that says ground next to it and it read 0....i'm using a fluke that automatically selects what you're reading so I would think its 0 volts

[budm]

Re: dynex hdtv/emerson hdtv troubleshooting

"OL" means over range. So are you getting OL or 0V? 0V then meas we will have to look at the STBY section. Right now you are getting the 160VDC for the main voltage to run the STBY power supply which will be the IC and the components around the IC that MARTINO had redlined.