Visio M320SL 32" LED 1080p Dead

[SgtRock]

Greetings BadCappers:

--I just bought another non working Vizio M320SL LED TV. It is completely dead, the LED does not come on, and it is unresponsive to the on button or the remote. The power supply has only the 5.2V working, no 12V or 24V. I suspect this is because the Main Board has failed, and is not providing the turn on signal, as was the case with the last M320SL I repaired by replacing the Main Board.
--My question is: How can I force the Power Supply to turn on, and can I do this, at first with all other cables disconnected. Please see pictures below.

"If you build a better mousetrap, you will catch better mice."
George Gobel 1919 1991

Best Regards
Clear Ether

[tom66]

Re: Visio M320SL 32" LED 1080p Dead

A resistor from 100 ohm to 470 ohm can be placed between REMOTE and 5.2V which should turn the PSU on.

Wow, that is a pretty anaemic power supply... Not even got any heatsinks... At least it has mostly decent caps.

[SgtRock]

Re: Visio M320SL 32" LED 1080p Dead

Greetings BadCappers:

--As per Tom, I hooked in a 220 Ohm resistor, and as we suspected the power supply turned on with all voltages present. I have bought a quite nice Sunbeam Electric Frying Pan for preheating, and am awaiting the Kingbo Flux, vacuum tweezers, and a Mediatek MT5396CUF J BGA ARM from AliBaba $15.36, I will then determine the pitch and order the correct stencil and leaded solder balls. When they come in I will attempt a reball with the new chip. But first I will clean the unleaded off of the new chip. At that time I will start a new "Reball" thread.
--In the meanwhile, is there any other testing I should do. Or are we stuck with it being a blown ARM like the last Vizio M320SL. In any case I am having a lot of fun. Thanks to Tom and everybody.


"Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level."
Enrico Fermi 1901 1954

Best Regards
Clear Ether

[SgtRock]

Re: Visio M320SL 32" LED 1080p Dead

Greetings BadCappers:

--I bought another non-operating M320SL Main Board. Installed the new bad main board, now when the set is plugged in the power supply comes on immediately, but the Visio logo does not light up. I checked all the Voltage Regulators, and they seem to be operating properly. Likewise the fuses and diodes seem to be fine. With the power off and the ground lead clipped to an input jack, and my Fluke 87 set to continuity mode, dragging the conductors of the two large FFL Cable Jacks produced an alarming number of beeps, indicating ground faults in the ARM chip. Is that a correct diagnosis? Is there any other checking I should do.

--My new ARM Chip should be in Monday, so then I can go about measuring the pitch, and then obtaining a stencil and leaded solder balls. I tried ordering Kingbo Flux from China, but the sent me Amtech NC-559-ASM Flux. So I ordered some Kingbo from a domestic supplier. Does anybody happen to know what the recommended uses of Amtech NC-559 ASM are. I seem to recall that it is not recommended for attaching solder balls, but I am not sure. Any advice would be appreciated.

"There are two possible outcomes: If the result confirms the hypothesis, then you've made a measurement. If the result is contrary to the hypothesis, then you've made a discovery."
Enrico Fermi 1901 1954

Best Regards
Clear Ether