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Post by tibimakai on Jan 17, 2017 14:00:24 GMT -5
I have looked at this one again and I have found missing(almost) V+3R3_HHH at IC9520. Even after replacing this IC, I still have only .3V.(page #88)
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Post by mastertech on Jan 17, 2017 15:46:06 GMT -5
On ic9520, what voltages do you have on pins 2,3,7
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Post by tibimakai on Jan 28, 2017 0:11:00 GMT -5
Sorry about not answering, I haven't visited the site for a couple of days.
Between the 3.3V and ground, I have a bit over 1 Ohm(!).
I have even applied 3V, with high amps and still nothing happened. I did not feel anything hot.
Pin #2, I have 5.6V(all the time)
Pin #3, I have 0.36V(after I reset the unit)
Pin #7, I have 4.74V(after reset)
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Post by tibimakai on Jan 28, 2017 0:12:51 GMT -5
I can't "see", what is going on at the bottom of the board. Something could be hot there, but I don't have a way of "seeing" that.
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Post by tibimakai on Jan 28, 2017 0:13:21 GMT -5
It could be a surge victim?
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Post by mastertech on Jan 30, 2017 13:13:27 GMT -5
Did the external 3v supply drop when connected or hold at 3v?
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Post by tibimakai on Jan 30, 2017 18:23:38 GMT -5
It held at, 3V 1.5A.
I'm taking home a thermal camera(borrowing), maybe I will see something with that, but I doubt it.
If I use the external power source and turn it on, without resetting the unit(it's in standby and flashing the MCAA LED), the bad component would heat up, or the unit has to be on, to heat up?
The problem with that is, if it stays on, for only like 10 seconds, there is no time to heat up the bad component. Am I right?
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Post by mastertech on Jan 31, 2017 17:30:49 GMT -5
If you are injecting an external 3v to pin 3 and it does not drop then I dont think you have a problem with something pulling it down. It would be the ic has failed.
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Post by tibimakai on Feb 2, 2017 22:37:01 GMT -5
I hav ereplaved the IC and nothing chaged.
Since then, I have used the thermal camera and I have seen a part, that it was getting hot next to the IC1602. I couldn't relly tell which one it was, but there is a IC1808 and a D1601. I have removed both ICs and the diode. After that, I have reset the unit and did not change anything.
Unfortunatelly, I had to retun the camera and I could not continue using it.
Eventually, I will get one for myself, but it may take a while.
I'm thinking about Flir TG167, TG165 or Fluke VT04.
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Post by tibimakai on Feb 7, 2017 11:14:13 GMT -5
I have started measuring with an ohm meter, the resistance to ground on the V+3V3_HHH rail.
I have found two points, where the resistance is the lowest(1.53-1.55 Ohm). Q901(SSM3K15FU) and IC610(TC74VHCT126AFK).
The rest, are between 1.67-1.73 Ohm.
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Post by mastertech on Feb 7, 2017 20:39:33 GMT -5
This is not a successful way to locate a shorted part. The rail is the same everywhere. You need to lift legs or remove parts until the short is gone.
I am still surprised your external supply did not also drop.
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Post by tibimakai on Feb 10, 2017 21:59:55 GMT -5
Sombody suggested, to remove the inductors at each IC and I ended up finding the short, at IC903. Lightning strike, or surge victim.
I still don't have 3.3V, only 0.8V(I used to have 0.3V). Still need to investigate this issue.
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Post by mastertech on Feb 10, 2017 22:10:27 GMT -5
If you believe ic9520 to still be good since you did change it then you need to check the feedback voltage to this ic at pin 5.
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Post by tibimakai on Feb 18, 2017 14:29:40 GMT -5
The IC9520 it was bad again(2.88V only). By replacing it, the receiver wanted to start up, but eventually it shut down after showing Sat/CBL on the screen.I hope the issue is, that the HDMI processor is not on the board.
Do you know, if it's enough to just replace it with another new IC, or it needs some kind of flash done to it?
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Post by mastertech on Feb 18, 2017 17:49:27 GMT -5
What ic are you needing to replace?
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