DYNEX DX55L-150A11 Randomly turns off

[dskall]

Re: DYNEX DX55L-150A11 Randomly turns off

I would recheck all solder joints for 5v

[Shane711]

Re: DYNEX DX55L-150A11 Randomly turns off

All the solder joints are good. The IC A6059H (N901) exploded and took out R905. I have replaced those but my 5V standby is erratic. I checked the near by capacitors and they test good.

[dskall]

Re: DYNEX DX55L-150A11 Randomly turns off

Is that with main board disconnected? Checked transformer connections? Connections at connector plug?

[Shane711]

Re: DYNEX DX55L-150A11 Randomly turns off

Yes, just the power board. It is removed from the TV. There is a component causing the problem. I asked what component should I suspect? All my connections are good. Budm probably knows this like the back of his hand, he dreams about it.

[freakaftr8]

Re: DYNEX DX55L-150A11 Randomly turns off

I suspect could be an opto, checked all diodes around primary bridge rectifier?

[Shane711]

Re: DYNEX DX55L-150A11 Randomly turns off

Yes, checked all the diodes. So you think the opto can fluctuate? I will have to check those tomorrow then and see what I find.

[Shane711]

Re: DYNEX DX55L-150A11 Randomly turns off

Well I got another board that had NO 5V(0V), the first board had fluctuating voltage. I removed the optos(Optocouplers) from the second board to the first and SUCCESS, the board now works. So you were right freak, it was the opto. Now I just got to get my crappy meter to work right so I can change out those resistors. The resistors on the second board seem perfect. Bought the second board as "For Parts" on eBay, I think it has some bad caps that are not popped.

[Shane711]

Re: DYNEX DX55L-150A11 Randomly turns off

I got the resistors on the board. I used regular 1/2 watt resistors. I don't know if it is normal but I noticed the length of my leads changes the resistance so I played around with it until I got 1.95 M OHM.

[Shane711]

Re: DYNEX DX55L-150A11 Randomly turns off

OK, so the board is not working all the time, It appears the Optocoupler that turns the board on is working sometimes but only sometimes. Can I replace the 817B Optocoupler with a 817C or a NEC 2561 ?

[Jason20]

Re: DYNEX DX55L-150A11 Randomly turns off

I know this is a old thread but I was having issues with my dx-55l150a11 tv shutting off/not turning on when power was applied.. also would just shut off whenever it wanted ... I ended up replacing power supply because when it comes to any component more then capacitors/fuse being bad I'm a nuub... it's been a couple weeks and hasn't acted up since... thanks guys for the help/suggestions on how to repair my tv..

[bluenote]

Re: DYNEX DX55L-150A11 Randomly turns off

Ok I'm pretty noobish and I guess I'll be replacing those resistors. Is anybody following this still that can help out with my stupid questions?

[nomoresonys]

Re: DYNEX DX55L-150A11 Randomly turns off

Shoot.

[bluenote]

Re: DYNEX DX55L-150A11 Randomly turns off

Shoot.

Thanks for speaking up! I'm going to source these resistors and I'll be back! For now, my only dumb question is, am I going to have to drain the capacitor(s) to work on this thing, or is leaving it unplugged for some days enough? And if so, can I just take some insulated wire and touch a leg of the caps to wall socket ground?

[nomoresonys]

Re: DYNEX DX55L-150A11 Randomly turns off

Use a resistor, touch both legs of the cap with each end of resistor, like you would with a wire.

[nomoresonys]

Re: DYNEX DX55L-150A11 Randomly turns off

Be careful with those big capacitor they can KILL, never touch the ends with your fingers, just assume they have a charge, make sure you are insulated from them when discharging, some use a resistor held with insulated needle nose pliers not bare metal pliers, here he built a simple discharge tool: https://www.youtube.com/watch?v=QNiBqF3Plw0

[nomoresonys]

Re: DYNEX DX55L-150A11 Randomly turns off

Use a resistor, touch both legs of the cap with each end of resistor, like you would with a wire.

DON'T use a wire, NEVER use a bare metal wire, touching that with your fingers can KILL.

[bluenote]

Re: DYNEX DX55L-150A11 Randomly turns off

Ok, I finally sourced the resistors! I have never opened a lcd before. It looks like there is 6 big bolts around the stand that need to come out to get the back off, but I was hoping not to have to put this thing on it's face to work on it. Anybody recall whether those are necessary AND if they compromise the stand? From outside it looks like they do. In that case I would I think have to lay it on it's face and work over it.
thx
(thanks for the info about the caps nomoresonys)

[nomoresonys]

Re: DYNEX DX55L-150A11 Randomly turns off

Sure lay it face down on a nice flat surface, I usually use a quilt or blanket under it to try to keep from scratching the screen.