HP PL4260N - Red Dots after YSUS repair - do not disappear after warm

[wirelicker]

Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm

Also, would you suggest I start a new thread?

[wirelicker]

Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm

Here's the location of the bad fuse.

[wirelicker]

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.

[tom66]

Re: HP PL4260N - Red Dots after YSUS repair - do not disappear after warm

Yes, 99% of the time on these a bad fuse is caused by the IPM module, under the black heatsink.

[wirelicker]

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