Ballast or Lamp or Something Worse?

[oldtech]

I was viewing a program on my HL-R4667W when the screen went black, came back on momentarily a couple of times and went black for good. The three blinking indicator LEDs "suggested" that the lamp needed replacement. I tested the lamp with a VOM minus the then knowledge that it was a mercury vapor type, so I ordered a replacement from Samsung. In brief, replaced the lamp engine, checked the cut-out switch, and I'm back to square one. The set will go through the power-on cycle but ends up with the three blinking LEDS. One additional sympton is that the set emits a high-pitched, intermittent whistling sound of loud to soft volume. I'm now assuming that the original DLP lamp was not the problem and the ballast may well be. Does it take special tools to replace the ballast and can it be bench tested using a VOM [volt-ohm meter]?

[Jake]

[oldtech]

Thanks Jake. Nothing like a good picture(s). Every illustration on lamp replacement I've seen in my manual, as well as literature received with the new lamp, was for some set other than mine. Go figure! Checking the ballast under op conditions sounds like a job for a "dead-man's stick," a device we used to discharge certain capacitors on a Collins 15KW HF transmitter. If you forgot to use it after opening the bay doors you could become a dead man. I'll decide what to do with the ballast once it's on the bench; however, a host of evidence is gathering and pointing in it's direction as the culprit in my case. Be well in TJ. Haven't been there in years.

[CraigDLP50]

Similar problem here:
Samsung DLP HLT5075S, began turning itself off randomly two months after warranty expired. Standby/Temp light
blinks, clicking sound, but no lamp fire-up; may do this for a few minutes or a few hours, then the TV will come
back on. The set may work for 5 minutes or 5 hours (perfect picture) before it shuts off again. Sometimes the
sequence changes: rather than red light/click, the set will make a buzzing noise two or three times and the green
LED will flash and the set will kick back on. During the re-up process I've sometimes heard a short popping noise.
Last night I replaced the lamp and the ballast, but that did not fix the problem. A tech I spoke with today said he
just replaced the digital control board in the same model, but it did not fix the problem.
I am wondering if it is a sensor tripping the TV off, or possibly the power supply intermittently dropping power to the
ballast. I've read that 320v to 380v needs to be maintained at the ballast to run the lamp.
I have yet to find anyone with a solution.

[oldtech]

Well, it's looking like something worse. New Lamp, Ballast, and Power Supply hasn't fixed the problem. Zero'd in on the power supply when the supply voltage to the ballast dropped to zero while trying to ignite the Lamp. What is consistent with this set is a "purring" noise which cycles
about every seven seconds. It appears that the noise cycles with the color wheel, i.e. starts with boot up, as does the color wheel, and stops when the color wheel stops on auto shutdown. Descriptions of bearing notes on various posting don't seem to apply in this case, i.e.
no screaming, and the wheel spins fast. I've read that a sensor is connected to the color wheel, which must be the cylindrical "can" with 2 wire connector, on top of the housing. Anyone familiar with the purring sound as described above or wheel sensor function?