Dynex DX-32L150A11 Standby Blink

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

Well before seeing your reply I went ahead and connected the fan I used to load the psu for testing (12v .22A) in parallel with iPhone charger to supply the main board. Figured in parallel it'll cut down the current going to the board.

Used some freeze spray and instantly noticed the 1.8 regulator warm up. Now my question is, could that be the fault or whatever it's powering? I'd imagine it'd be connected to the processor with a voltage that low at its output.

[tom66]

Re: Dynex DX-32L150A11 Standby Blink

I don't know what you mean by doing that... You'll probably find one power supply or another will take the whole load so it should be the same as with PSU? A 1.8V regulator could be the cause, you can remove it for a test (the set will not work right but it should have 5V steady.)

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

I don't know what you mean by doing that... You'll probably find one power supply or another will take the whole load so it should be the same as with PSU? A 1.8V regulator could be the cause, you can remove it for a test (the set will not work right but it should have 5V steady.)

Doesn't current divide in a parallel circuit? That's why I connected the fan in to cut amps going to the main board. I could be wrong but it was quick thinking to limit current since I don't have proper resistor. Will remove regulator and see what happens.

[tom66]

Re: Dynex DX-32L150A11 Standby Blink

Doesn't work without resistors to divide current between equal or dissimilar voltage sources.

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

Doesn't work without resistors to divide current between equal or dissimilar voltage sources.

Isn't a fan a type of resistor (load)? Just trying to learn as a go. Thanks for helping along with this. Been helpful

[tom66]

Re: Dynex DX-32L150A11 Standby Blink

In a way but not really, also it would need to be in series with one of the power outputs to do such a job. (A computer fan has transistors in it to switch various motor windings, it switches rapidly between near zero and near infinite resistance.)

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

In a way but not really, also it would need to be in series with one of the power outputs to do such a job. (A computer fan has transistors in it to switch various motor windings, it switches rapidly between near zero and near infinite resistance.)

Wouldn't wired in series drop the voltage at the output?

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

Removed that regulator and now I have steady 5.20v at that rail and steady standby light. Power button doesn't do anything.

Anyway to test the regulator with ohmmeter? I have a bad feeling there's a short at its output somewhere and regulator is good.

[tom66]

Re: Dynex DX-32L150A11 Standby Blink

What resistance, board powered down & unplugged from power board, do you get across 5V now?

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

From 5v pin of main board to ground I get infinite resistance

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

But from output pad of where the regulator would be to ground I get .2ohms

[tom66]

Re: Dynex DX-32L150A11 Standby Blink

That sounds like you do have a short. The next thing to do would be to try tracing the short on 1.8V -- but unfortunately you WILL need something like a 1.5V power supply (maybe a 1.2V NiMH.) An ordinary alkaline cannot supply enough current.

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

Damn. Know if I can find the service manual/schematic for this anywhere?

[tom66]

Re: Dynex DX-32L150A11 Standby Blink

Amazingly, yes!

Detailed schematic of power board and main board.

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

Awesome! Thanks

[tom66]

Re: Dynex DX-32L150A11 Standby Blink

Which reg is it that has the short? Nxxx?

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

N602

[tom66]

Re: Dynex DX-32L150A11 Standby Blink

That is a 3.3V reg (adj setup) on the schematic -- is that correct?
Lift C661, see if short goes.

[ohmmy]

Re: Dynex DX-32L150A11 Standby Blink

The part number on the regulator is 1117

I've already tried lifting c661 and replaced c660 both made no difference

what page of the manual is the mainboard schematic?

[tom66]

Re: Dynex DX-32L150A11 Standby Blink

Page 31 and others in that area. Just confirm that it is correct schematic, check a few component references to be sure, for example reg should have R603, R604 nearby.
The short is on VCC3.3V if N602 and sch is correct, which is standby 3.3V rail. (Don't confuse with 3.3V_NORMAL)