Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
I disconnected power supply to zsus and tested resistance of both fuse-holders to the frame, and the holder which had the bad fuse was grounded (about 1 ohm), and other holder was around 49 k-ohms.
I also rechecked resistance on the vzbias mosfet (disconnected power) and got much different readings. Probably did it wrong before.
G: 97 k-ohm
D: 97 k-ohm
S: 5 ohm
tab side: 97 k-ohm
wirelicker
Member
Last Activity: 08-26-2018, 04:03 PM
Joined: 03-08-2014
Location: McKinney, TX
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
I'd like to learn how to think this thru, so let me know if this is good logic... Putting in the good fuse must be opening a circuit that probably has a short which is triggering a safety fault which shuts off the tv. Since the fuse is on the zsus, the issue is probably a short that's on the zsus, in the path of the bad fuse, and it's significant enough to trigger a shut-off fault.Leave a comment:
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
Here's the location of the bad fuse....Leave a comment:
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
Also, would you suggest I start a new thread?Leave a comment:
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
I found a bad fuse on the Zsus. Replaced it, and now the tv won't stay on. It acts like a throws a breaker a second after coming on. When I put the bad fuse back in, it powers up, and I get the same purple/pink and muted screen. The fuse I got to replace it matches spec, (4a, 250v, slow) but is glass instead of ceramic. Since the tv has 5 of the same fuse in different places, I juggled them and tested again, same result.Leave a comment:
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
No resistance when powered on.Leave a comment:
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
Let me try that again. Next to the ribbon there is an arrow printed on the board labeled zbias which points to an n-channel mosfet (fqb 27n25 g36). It registered.
G: 7.3
D: .047
S: .138
Another thing I noticed, the heatsink wasn't getting warm on the zsus.Leave a comment:
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
Here's what I got, tested Zbias and others at the white connector in photo...
1. OE 0
2. Zbias 2.7
3 Sus_dn 0
4 Sus_Up .26
5. ER_dn 0.082
6. ER_Up .31...Leave a comment:
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
zbias is 2.6 - 2.7Leave a comment:
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
Voltages coming in are good.
Vs 188. Va 66.
Attached a pic of the ZSUS.Leave a comment:
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
Tom,
Thanks for your reply. I've attached a pic. I tried to include the cloned imaged (google home page) on both the laptop and tv. As you can see, the camera seems to have adjusted it, because you can't see anything on the laptop. Just wanted to clarify, there is a huge difference between what it should be (like the laptop) and what it is.
Does this confirm your diagnosis?...Leave a comment:
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Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm
CapKid.
I also have a HP PL4260N that's been garaged since it was 2 yrs old, apparently due to the same problem, and am hopeful I could enlist your help to get it usable. It sounds like it's the same problem that you've been fixing. Lots of pink/red sparkling, images are terrible, lack brightness and richness, and generally jacked up.
Could you let me know what other symptoms to look for, and if it's something you believe you can fix?Leave a comment:
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