Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on
"OK, this morning, I have desoldered one pin of F301, powered up the board, and taken the following voltage readings...
The big cap reads 336v
F301 disconnected [if I'm testing it correctly] 0.0 to 0.01 on setting 20 DCV
The voltages across the the connector pins...
1 [B-DIM] 0.0
2 [15V] 13.5 to 14.5 unstable
3 GND
4 GND
5 GND
6 [5.2V] 5.0 to 5.2 unstable
7 [5.2V] 5.0 to 5.2 unstable
8 [DCR] 0.0
9 [ON/OFF] 0.0"
"Is it safe to power up with the fuse out of circuit?"
Isn't that what you did on post 14? So now you will need to have the main board connected to the power supply board to see if the you can turn the monitor on and off (power LED goes on and off). The fuse can be left off, it is for feeding the voltage to the inverter circuits. I am trying to find out if the main board will response to power on/off switch. Report the voltage readings in the same format as above when you test with all the boards connected.
I still did not get the answer about the voltage on the pins when the fuse was in place in post3. What I am trying to find out is that if the fuse is connected then there is no voltage at the pins or not, then the fuse is lifted then you get the voltage, that will tell me it has shorted circuits in the inverter section that causes the power supply to shut down. You are getting voltage now when the fuse is lifted, so do you get the voltage if the fuse is back in place? That is why I asked the question in post 3 since I have no idea if the voltages are present or not from the beginning.
"OK, this morning, I have desoldered one pin of F301, powered up the board, and taken the following voltage readings...
The big cap reads 336v
F301 disconnected [if I'm testing it correctly] 0.0 to 0.01 on setting 20 DCV
The voltages across the the connector pins...
1 [B-DIM] 0.0
2 [15V] 13.5 to 14.5 unstable
3 GND
4 GND
5 GND
6 [5.2V] 5.0 to 5.2 unstable
7 [5.2V] 5.0 to 5.2 unstable
8 [DCR] 0.0
9 [ON/OFF] 0.0"
"Is it safe to power up with the fuse out of circuit?"
Isn't that what you did on post 14? So now you will need to have the main board connected to the power supply board to see if the you can turn the monitor on and off (power LED goes on and off). The fuse can be left off, it is for feeding the voltage to the inverter circuits. I am trying to find out if the main board will response to power on/off switch. Report the voltage readings in the same format as above when you test with all the boards connected.
I still did not get the answer about the voltage on the pins when the fuse was in place in post3. What I am trying to find out is that if the fuse is connected then there is no voltage at the pins or not, then the fuse is lifted then you get the voltage, that will tell me it has shorted circuits in the inverter section that causes the power supply to shut down. You are getting voltage now when the fuse is lifted, so do you get the voltage if the fuse is back in place? That is why I asked the question in post 3 since I have no idea if the voltages are present or not from the beginning.
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