I'm new here... I hope this is the right place to look for help. Just this week, my January 2009 HL67A750A1FXZA has decided not to start. I push "power" and the green STAND-BY light on the lower right pulses 15 times, then the cooling fans run for a moment and stop. It does this twice more, then all three lights blink. Here's what the manual says about that:
(it sez: "If turning the LED on fails, the set automatically tries turning the LED ASSY on 3 times. If all attempts fail, all LED's on the front panel will blink. Check the LED ASSY, LED Driver and the Subpower or SMPS and replace them if necessary").
I've gone through most of the troubleshooting flowchart in the service manual
(page 34/4-2); and everything so far has checked out OK. I'm at the last "diamond" at the bottom of the chart, where I have to solder a wire on R9010 to operate the driver in internal mode to see if the author thinks I need a new Driver or DMD. I really don't want to risk damaging the board with a soldering iron, and I'm a little skeptical of the flowchart, since it doesn't mention anything about testing the LEDs (which I've read about in several forum posts).
In addition to the flowchart items, I've also measured voltage on the LEDs, both from the colored supply wire to ground (on an RCA jack), and across the LED (colored wire to white wire). Here's a pic (ignore the circle, it's the wires there that I'm talking about):
Where I measured:
Blue: 15.8 to ground, 0.10 across LED
Green: 13.6 to ground, 2.3 across LED
Red: 16.0 to ground, 0.01 across LED
I tried to start-up with each of the three LEDs unplugged, and with both the blue & red unplugged. Nothing changed.
I've read posts at justanswers.com saying that anything other than 2-4 volts across an LED indicates a dead LED. I also read there that dead LEDs will not respond to a 9 volt battery. I held a 9 volt battery to each LED, and each one lit up.
Any thoughts would be appreciated!