The faults are located on the PSU/Inverter Boards.The Manual can be found at:
http://www.electronica-pt.com/index....tdown/id,4123/
CCFLs were tested using a test power supply and are fine.The test CCFL's were also tested to ensure they could be used, and they were fine as well.Various faults have already been repaired on the Power Supply,including Caps LP1337 etc,and all the Secondary voltages now read as they shoud
Board 1)
a)The Board was connected to the Logic card,and the Control panel,with the test Lamps.The PC was plugged into the Logic card,but not switched on initially.
b)On applying Mains Power,Both Power led and the Lamps were pulsing in sympathy with each other AND with no ON signal appled,as the PC was still off.
Board 2)
a)Set up as is in (a) above,Power LED to Green and no pulsing of LED and
BL's.LED then went into Power Saving and reverted to Amber,again no pulsing.
b)PC switched on, and the Logic recognises it and and Power LED goes Green,and now statrts to pulse on and off,as does the BL's.Irrespective if one or both lamps are plugged in to the top or bottom sockets.If I remove the CCFL's the LED continues to pulse,until Power removed.
c)with PC VGA plug removed from the Logic card,so there was no ON voltage.An external voltage was then applied instead and the Power LED and CCFL's started again to pulse together,BUT continued to do so when the external signal was removed ??.The latter was tried on Board 1,and that simply flashed once and then switched off.
The Inverter Controller is OZ9938GN,and the Mosfets are Dual 'N'Channel AP9971GD's.The supply to the Controller is also fine.
Measuring the Mosfets do not seem to indicate a short,and all of them on Both boards measure the same on Diode testing ??.
The Output transformer secondaries ,are all in spec.
I am now at the stage that I can't see the wood for the trees,and really need some input please.
http://www.electronica-pt.com/index....tdown/id,4123/
CCFLs were tested using a test power supply and are fine.The test CCFL's were also tested to ensure they could be used, and they were fine as well.Various faults have already been repaired on the Power Supply,including Caps LP1337 etc,and all the Secondary voltages now read as they shoud
Board 1)
a)The Board was connected to the Logic card,and the Control panel,with the test Lamps.The PC was plugged into the Logic card,but not switched on initially.
b)On applying Mains Power,Both Power led and the Lamps were pulsing in sympathy with each other AND with no ON signal appled,as the PC was still off.
Board 2)
a)Set up as is in (a) above,Power LED to Green and no pulsing of LED and
BL's.LED then went into Power Saving and reverted to Amber,again no pulsing.
b)PC switched on, and the Logic recognises it and and Power LED goes Green,and now statrts to pulse on and off,as does the BL's.Irrespective if one or both lamps are plugged in to the top or bottom sockets.If I remove the CCFL's the LED continues to pulse,until Power removed.
c)with PC VGA plug removed from the Logic card,so there was no ON voltage.An external voltage was then applied instead and the Power LED and CCFL's started again to pulse together,BUT continued to do so when the external signal was removed ??.The latter was tried on Board 1,and that simply flashed once and then switched off.
The Inverter Controller is OZ9938GN,and the Mosfets are Dual 'N'Channel AP9971GD's.The supply to the Controller is also fine.
Measuring the Mosfets do not seem to indicate a short,and all of them on Both boards measure the same on Diode testing ??.
The Output transformer secondaries ,are all in spec.
I am now at the stage that I can't see the wood for the trees,and really need some input please.
Attached Files
Comment