Re: two MINUTES on, then off-on, then black...
Sure, hope this helps...shots with and without flash. Orientation is same as component-side PCB shot posted originally.
Cheers - Dave...
808dude
Member
Last Activity: 07-11-2016, 11:40 AM
Joined: 06-01-2016
Location: Honolulu
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Re: two MINUTES on, then off-on, then black...
Epilogue?
I was hoping this would be a simple "thanks-for-the-mentoring" email, but not quite.
I had no caps even close to the suspected-bad one, so I ordered a replacement from ebay out of China, which came a couple weeks ago, and I finally got around to installing it today. I was already declaring victory because the monitor went for 10 minutes without any recurrence of the lamps-out problem (that's more than twice as long as it previously took) but then at about 11 minutes, blackness...
...Leave a comment:
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Re: two MINUTES on, then off-on, then black...
Thanks, Bud...that cap has a 400V/100uF rating...might I be OK with a lay-around of at least 400V, and perhaps exceeding the 100uF? I gotta go rummage. I'm thinking it might not be worth a purchase of identical value...and if this doesn't work, maybe it's a write-off?Leave a comment:
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Re: two MINUTES on, then off-on, then black...
Bud,
I'm surfacing again with latest tests:
1) C810: started @ 5V, then over the course of a little less than 5 minutes, dropped steadily to about 3.5V - upon "black-screen," it returned to 5V.
2) C803: much the same - 5V to start with, only more quickly dropped to about 3.3V (under two minutes) at which point I got the black screen and return to 5V. (I take it the increasing speed of voltage-drop is a heat-up thing?)
3) Big main cap: I recalled it wrong in...Leave a comment:
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Re: two MINUTES on, then off-on, then black...
Thanks Bud, I will repeat that check, on the two caps you mentioned (not the other similar ones?)
I accidentally did start measurements on the primary filter cap before you wrote the above, finding that it started at 165V, dropping about 10V in 30 seconds and holding there for a minute, at which point I realized I wasn't measuring the right voltage and stopped (screen hadn't begun doing the off-on thing yet.) Smoking gun?Leave a comment:
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Re: two MINUTES on, then off-on, then black...
I'm back on this after some distractions...
I soldered a twin-pair onto those cap leads (the one nearest the dark inverter-xfmr you called out on the right midriff of the image, it's 35V/470uF) and monitored as I think you suggested, Bud.
I had 23V right off, dropping to 17.75V after a few seconds, where it held while the image looked more or less normal (perhaps a bit dim, but livable). About two minutes in, when the CCFLs began going black (three seconds black, then a flash of normal illumination, repeating),...Leave a comment:
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Re: two MINUTES on, then off-on, then black...
Thanks, Bud!
Clarifying, maybe - your last word "longer..." did you actually mean "for less time?" I'm thinking if it's heat-related, and I "fuel the fire" by adding heat to those caps as you suggest, and they're the problem, it would reach the breakdown point sooner vs. later. Maybe I missed your point, though.
--DaveLeave a comment:
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Re: two MINUTES on, then off-on, then black...
Thanks Bud...
If needed I can provide some daylight-photos, but weather's not conducive right now.
For now, I'm guessing the action's going to be on this board:
The only other for-real board is this:
...Leave a comment:
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two MINUTES on, then off-on, then black...
I've got a lay-around Sceptre X24WG that I would like to either take a short time to repair, give it the ol' heave-ho, or heave it gently to someone who'd use it after repairing, since I really don't need it. (it would be a Honolulu-pickup freebie, though...)
Symptoms:
From cold, it comes on and looks just slightly dim for a few minutes, but otherwise the image looks fine. After those first few minutes (not seconds), backlights start cycling off/on every second or so for a while. This dithers into plain old blackness by a few minutes later.
Only after a long... -
Re: New Members - please post your introductions here
Man of Few Words (this time only) seeking fast track to enlightenment.
Aloha,
DaveLeave a comment:
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