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Post by crudeau on Dec 15, 2013 11:08:38 GMT -5
Hi guys! My avr 989 is having some issues. Problem is that it just goes into protection mode. No LCD or anything. Just protection mode. I can hold the two button reset and then I get relay clicks and the LCD screen flashes. So I'm pretty certain the power supply is fine. I did find that one of the large transistors on top has a short. So I cut the legs but the short is on the board somewhere as I still get a short on the board. So I'm curious where I should go from here. How much can I remove and still fire the unit up. I figure that would get me down to the board that has the short and then I can go from there. Or do these units have a known problem that I can just go right into.
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Post by mastertech on Dec 15, 2013 11:32:11 GMT -5
What transistor is it that you cut, meaning, what board is it on and what is its location id on the board?
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Post by crudeau on Dec 15, 2013 11:41:52 GMT -5
It was on the top most board. The one closet to power supply. Was showing a dead short on center pin and pin closest to power supply. I saw online that I can unplug board completly and retest for power up. Something. Nothing but protection mode unless I try the reset procedure. Not even a relay click when I plug it in. Just flashes red
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Post by crudeau on Dec 15, 2013 11:43:31 GMT -5
I'm very confident my issue is in the power supply. Aside from a blown channel but I can't find anything schematic wise to give voltages to check and resistor values to look for
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Post by mastertech on Dec 15, 2013 11:56:53 GMT -5
I have what I need to help you but I need to know the part location id (number stamped on the board where the part is) like Q??? or TR???.
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Post by crudeau on Dec 15, 2013 12:19:40 GMT -5
Board 8u-110041-1. Jb01 and jb06 are shorted. But here's the of thing I have removed the board and there's no short now. So something elsewhere has it shorted. As of now I have the unit stripped down to just the main board installed. Not sure where to start testing
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Post by mastertech on Dec 15, 2013 12:35:00 GMT -5
Ok, just slow down and relax and I will guide you through what to do. So we now know it is the regulator board and from what you gave me I can determine your looking at TR802. Now your saying with the board removed it's not showing a short, but you said you cut the legs on this transistor. Or are you now testing on the board itself?
I need you to be very specific in your answers so I can follow along and know exactly what you are looking at and testing.
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Post by crudeau on Dec 15, 2013 12:35:07 GMT -5
To me anyway seems like something between that board and power supply has crapped out. Just not sure on what readings I should be getting I've done quite a few tvs but I can always find a schematic so I can find a schematic and I can from there replacing regulators that output wrong voltages.
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Post by crudeau on Dec 15, 2013 12:37:38 GMT -5
When I first opened the unit up. I throw the damn on those transistors and just tgat one was shorted. So I cut the legs. Once cut the pins on the board still should a short. So I stripped done the unit. With tgat board out of the chassis I show no short now
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Post by crudeau on Dec 15, 2013 12:38:10 GMT -5
Lol. Damn was suppose to be dmm.
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Post by mastertech on Dec 15, 2013 12:41:33 GMT -5
The harness that was connect to that board at connector CX077, set your DMM to diode scale and test between pins 2 and 3 and tell me what you get.
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Post by crudeau on Dec 15, 2013 12:49:01 GMT -5
10.14 on the board connector
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Post by mastertech on Dec 15, 2013 13:06:40 GMT -5
How about the harness part, same wires for those pins?
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Post by crudeau on Dec 15, 2013 13:08:44 GMT -5
I get nothing. right now the whole unit is apart. SO I have the boards in my hands not in the unit. Should I reassemble everything?
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Post by mastertech on Dec 15, 2013 13:11:25 GMT -5
Let me see where that harness goes and you can test on that board. Give me a minute.
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