Awesome! I wonder how the cable became so damaged in the first place? Factory/assembly error?
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Awesome! I wonder how the cable became so damaged in the first place? Factory/assembly error?
Could have been, could have been the previous owner. Those ribbon cables (at least the small ones) are not that tough. Now the bigger one leading to the TCon appears to be pretty strong, I also ran a continuity check on it. Thanks for all your help.
Have you ever stopped to think and then forget to start thinking again?
As a very wise man once said on this forum: "Of all the things I have lost I miss my mind the most."
That is great news and I am glad you did not give up on it. I wonder if your EEPROM is the problem or not from the beginning.
That is a question I thought of. But it might have been all three the LDO's, EEProm and the cable. Who knows. Just glad it is repaired. This is something to remember when one of the symptoms is the remote does not work. Thanks for all your help.
Have you ever stopped to think and then forget to start thinking again?
As a very wise man once said on this forum: "Of all the things I have lost I miss my mind the most."
Killian, you said that you reflowed the solder on U48. I can't seem to locate U48 could you give me some help in locating it? Thanks in advance!
It is the large square chip has a white rectangle around it and other components. It is the main video chip on the main board I believe. Should be sort of left middle of the board. Has MediaTek written on it.
Have you ever stopped to think and then forget to start thinking again?
As a very wise man once said on this forum: "Of all the things I have lost I miss my mind the most."
I didnt have the same problem as the OP.. But I found this post because I was searching for E320VL.. My problem was TV would power on and work for about 10 minutes and shut off (sleep timer off). Sometime it would do this, and then start powering on and off by its self... So I recapped the board because I had the caps handy and still had the same problems.. I did A LOT of digging on the net and found a tip that a guy said that he had similar problem.. He said for some unknown reason, if he went to the audio settings and changed from Dolby to PCM it cured the problem.. Well holy crap, it does work... My tv has been running for 36 hrs straight and going strong.. I have since went ahead and did a total factory setting reset.. Just a tip for others that may find this thread with similar problems to mine..
I have 5.05 volts at power supply board and no 12 volts, but can turn on 12 volts with the 3 volt input to the power supply board, therefore think the power supply board is ok.
There appears to be low voltage problems on the mainboard at the regulators, but without the schematic I do not know which parts affect the others.
I have not seen anyone report the resistance readings at all three of these regulators, but here are my readings in ohms, measured from pins 1, 2, and 3 relative to ground:
U4 74.7, 17.1, 1000+
U5 46.7, 136.6, 0.3
U8 0.1, 1.2, 0.3
Since pin 3 is the voltage input to these regulators, it appears there might be a short somewhere. There is no voltage in standby mode on either U5 or U8, but U4 seems to have some good readings.
Should there be voltages at U4, U5, and U8 in standby mode (without the 12 volt supply on)?
I'm far from an expert, but are those readings taken with the black lead of the DMM to chassis ground, and the red lead to each of the three leads, using dc voltage 200v setting? If so, something is way off. The input voltages should be near 5v or 3.3v or something low like that. It almost looks like something is flaky with what you're using for ground, or you have it on ohms?
One bad thing about Digital Ohm meter when you try to read resistance on the board that still have residue DC voltage still left charge the caps, it will mess up the reading. Put the meter in lowest DC scale and take the reading, it is has as small as 0.5V reading, when you do the Ohm reading on that same spot, the resistance will be way off because the DC voltage of the circuit will mess up the input circuit of the meter (it does not damage the meter). So make sure to discharge the caps.
Also the adjustable LDO will have low value resistor (100~200 Ohms) between the ADJ pin and the output pin, and another low value between the Adj pin and Ground, so the output resistance will be at least the value of those two resistors in series.
Thanks Worminizer for your comments. As I mentioned in the post these readings are in ohms, and that there is no voltage measured at U4 and U5 (zero volts). Could be bad regulators, or other shorts on the board I suspect.
Thanks budm for your comments. No voltages were measured on U4 or U5 so something must be shorted somewhere. This failed during a storm, so maybe a spike came in through the cable connection and did some damage to this board. Without a schematic, I may not waste any time with this.
Thanks Worminizer for your comments. As I mentioned in the post these readings are in ohms, and that there is no voltage measured at U4 and U5 (zero volts). Could be bad regulators, or other shorts on the board I suspect.
Correction: I meant to say U5 and U8 measured zero volts on all pins, and U4 measured normal voltage.
Thanks budm for your comments. No voltages were measured on U4 or U5 so something must be shorted somewhere. This failed during a storm, so maybe a spike came in through the cable connection and did some damage to this board. Without a schematic, I may not waste any time with this.
Correction: I meant to say U5 and U8 measured zero volts on all pins, and U4 measured normal voltage.
I didnt have the same problem as the OP.. But I found this post because I was searching for E320VL.. My problem was TV would power on and work for about 10 minutes and shut off (sleep timer off). Sometime it would do this, and then start powering on and off by its self... So I recapped the board because I had the caps handy and still had the same problems.. I did A LOT of digging on the net and found a tip that a guy said that he had similar problem.. He said for some unknown reason, if he went to the audio settings and changed from Dolby to PCM it cured the problem.. Well holy crap, it does work... My tv has been running for 36 hrs straight and going strong.. I have since went ahead and did a total factory setting reset.. Just a tip for others that may find this thread with similar problems to mine..
Well it lasted about 2 months and started shutting off again and the above fix wouldnt fix it again.. So I guess its something else now..
Normally I just lurk around these forums in silence, but I just wanted to say I've fixed three of these tvs simply by reflowing the ram, main control ic, and the eeprom using my rework station and some good ol' rosin flux (yes I used flux cleaner afterwards). One froze at startup. The second one would not react to the power button being pressed at all. And the last one would start sometimes. The only one I did something different on was the one that would not start up at all. I replaced all of the adjustable regulators using part number AS1117. All have been working great thus far.
Thanks for sharing that I have been thinking besides the old voltage regulators going bad that all these main board failures with Vizio must have a common problem, maybe that's it..
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