Re: Zenith HDV420 Won't Come Out of Standby
That info doesn't give me any more ideas. It will probably stop working if you unplug it. I would recommend that you ask scotcho to send you his power supply board (or you can send him yours) to see if the problem is with it or with the main board. Then whichever one of you can, start testing at the component level....
gfgray
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Last Activity: 09-27-2016, 10:31 AM
Joined: 07-14-2009
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Re: Zenith HDV420 Won't Come Out of Standby
If you and Scotcho are willing, the next step is for Scotcho to send at least his PSU and maybe also his motherboard to you before your unit fails completely. Then, you can swap parts out and see if the issue follows the PSU or motherboard.
Gordon...Leave a comment:
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Re: Zenith HDV420 Won't Come Out of Standby
Thanks for the feedback Scotcho. You are smarter than me to use a current limiting resistor for safety instead of a jumper.
As an update, this trick eventually stopped working on my box after many months. I tried replacing several of the large SMT caps on the mainboard, but it did not help. So I ended up tossing mine. Too bad, because I could have loaned you my power supply board to see if the problem is with it or with the main board. When yours finally dies, hang on to it until someone else replies to...Leave a comment:
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Re: Zenith HDV420 Won't Come Out of Standby
np, hopefully all the free bumps will make it easier to find for the next person who has this problemLeave a comment:
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Re: Zenith HDV420 Won't Come Out of Standby
No capacitors were replaced on the power board. I was going to start guessing as to which caps needed to be replaced. But then I tried this. I posted in case someone else on the internet has the same problem.
NxB, please note that a set top box tuner does not have a screen and therefore does not have a backlight. Am I the only person that knows what a set top box is? lol Anyway it has been humming along nicely for like 4 months - except when someone hits the power button.
Edit - I think I measured only a few...Leave a comment:
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Re: Zenith HDV420 Won't Come Out of Standby
It is actually a set top box to be used with HDTVs that don't have an HD tuner built in. This workaround is just tying 5V or whatever into the "wakeup" wire. I don't recall what exactly they are labled. I think it has more to do with energy saving than with safety. I think this prevents the power supply from going into energy saving mode and shutting down certain power circuits.Leave a comment:
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Zenith HDV420 Won't Come Out of Standby
If you have a Zenith HDV 420 HD STB and all you have is the red standby light which will not turn green, this is the workaround. Jumper the red wire going between the power board and the main board to the gray wire right next to it.
The limitation of this fix is that if you ever hit the power button, you will have to pull the plug and plug it back in before it will give you the green light again.... -
Re: Issue with Westinghouse 19" LCD Monitor (large pics)
The FETs won't have to be in circuit to check for this short. Put one probe on the through hole for the gate of FET 1. Put the second probe on the through hole for the gate of FET 2. Is it zero resistance? Does it form a diode in either direction?
Also, are you sure the caps are correctly polarized?Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Yes, I am asking you to check for a short BETWEEN the gates of the two FETs (elswhere in the circuit).Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Wow, you guys are hard core. Bill suggested earlier this could happen if both FETs are conducting. Can you check for a short between the gates of the two FETs?Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Depending on what the problem is, it is possible the lower Rds on of the the On Semi FETs could help kill the capacitors faster. But I'll take my chances with the better components. I'll post here if the fixed monitors ever fail. I guess it took 2yrs for the originals to fail.Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
I wouldn't go back and redo any repairs, but I trust On Semi more than A-something or whoever they are. Clearly the caps fail first though. So it may not matter in the end.
My friend works for a company that runs their monitors 24x7. These Westinghouses are failing left and right.
Edit - Mouser stocks another heatsink for the TO-220 package if that Aavid Thermaloy I spec'd is OOS. But the Aavid is easiest to install.Last edited by gfgray; 07-16-2009, 06:12 PM.Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
I couldn't find the originals for sale. Also, since they failed, I thought a better FET was in order anyway.
BTW, a couple Westinghouses that I fixed only need new capacitors.Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
I fixed 4 or 5 of these at the beginning of the year but didn't know where to share my knowledge. Here is my post on AVSForum. All these monitors are still running strong. Note that I had a different idea on why they are failing. I suspect the 3913 part doesn't have this flaw.
[URL=http://www.avsforum.com/avs-vb/showthread.php?t=1113012]Westinghouse L2046NV 20" LCD Backlight Out.[/URL]
If you have a Westinghouse L2046NV with a DAC-19M005 power PCB and your fluorescent backlight is out,...Leave a comment:
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