Megmeet mlt169b whatis the zener voltage of "Z3" which is connected to a 20 ohm resistor?

I'm not sure what your question is. A zener diode is a voltage regulator of sorts. The zener voltage is the avalanche voltage...the voltage that the zener diode will maintain when it's connected in series with an impedance, usually a resistor, IF the voltage across the zener diode and the impedance, in series, is greater than the avalanche voltage (zener voltage), and the polarity of the voltage across the zener diode is thus: positive cathode, negative anode (i.e., reverse bias). The excess voltage (the margin) appears across the impedance. Zeners are often used as voltage reference diodes in regulated power supplies. Does this answer your question?

Pls check secondary 12v zener diode

R12 & R13 value is 47 ohms for both resistors.

Most failures on this LCD are due to defective capacitors in the power supply board.
The defective capacitors are 1000uF/16v, the reference designators are EC18, EC19 & EC20 and since the light is flashing. Z3 a 27v 1w zener diode might be shorted and two 10 ohms surface mount resistors might also be defective.
If you are fixing it yourself, you can use 1000uF/25v or 35v as long they fit in the space provided by design. Radio shack should carry the capacitors and possibly the zener diode but not the 10 ohms surface mount resistors.
Let me know if you need further assistance.

This series of TVs has a famous issue with the power board (part number MLT166A or similar). Several capacitors and zener diodes burn out causing some resistors to burn as well. If you are capable of doing component level repairs check capacitors on the board and zeners Z2, Z3, Z4, Z5 and resistors around them. If you prefer to spend hundred bucks and simply buy the working power board for it - ebay is your answer.

If Z3 was shorted, there are 2 surface mount resistors that were damaged when Z3 became shorted and they have to be replace as well. The reference designator for the resistors is R65A and R65B, their value is 10 ohms and 1206 is the body size of the resistors.

If Z3 was shorted, there are 2 surface mount resistors that were damaged when Z3 became shorted and they have to be replace as well. The reference designator for the resistors is R65A and R65B, their value is 10 ohms and 1206 is the body size of the resistors.
If you need further assistance or to get the power supply repair, write to [email protected]

you also have to replace the 2 resistor on bottom of the board they are 10 ohms each they are surface mount 1/4 quarter watt each they are next to z3, also have to replace the 3 caps. I have fixed 4 units with the same problem this must be obviously a design issue since many of these tvs have the same problem.
hope this helps

I had the same problem; the blinking light problem is caused by a bad power supply. It try’s to power up but senses a failure so it shuts down and just keeps repeating this process. I troubleshot the problem and found that zener diode Z3 (27volt 1 watt) was shorted and zener resistor forgot designation (2 surface mount 10 ohm resistors in parallel) were open. The zener is under a heat sink so it is hard to see. Also there were 4 1000uf capacitors that were bulging so I changed them as well. I got the parts from digikey for 20 bucks and its now working fine. This was a lower cost TV at the time of purchase so it seem the manufacture used low quality parts and I would suggest trying to return the TV to Costco before fixing it. Good luck.

deebo24,
You just had to buy the cheap one... These units have an all too common failure in the SMPS, (made in China) which is a MLT166A part number if you're buying the whole supply. But the SMPS can easily be removed in this unit and after you access it you'll find three 16v/1000mf caps that have failed EC18, EC19 & EC20, together with Z3 a 27v 1w zener diode... You can replace the caps with a 25v/1000mf if you order them to size. The higher voltage will provide a greater reliability...
If any or all that sounds too confusing you can simply replace the entire SMPS for just about $70.00 plus shipping. They're available at Fox International 888-498-7278 but don't be surprised if their temporarily out of stock and on backorder. Techs buy these things by the case because they are that common a failure.
Bill