I would appreciate some leads - I'm having trouble narrowing in on the problem.
Symptoms, when connected to mains, will display red STBY light on the front of the TV, but when I attempt to turn it on via the remote or the TV press-button it briefly goes off and then back on again (less than 1 second) back to a steady red STBY light (ie. no sequence of error flashes). When this happens there is the sound of a relay activating - sounds like a single click but based on my testing it looks like it closes and then opens very shortly afterwards.
Samsung 64” Plasma TV, Model: PS64E550D1MXXY.
SMPS Power Board: BN44-00515A
Logic Board: LJ41-10272A
Main Board: BN41-01802A
X-MAIN: LJ41-09452A
Y-MAIN: LJ41-09453A
Y-Buffers: LJ41-010270A, LJ41-010271A
Overview image of board layout: PS64E550_overview_annotated.jpg
Connector CN801 Pin-outs: PS64E550_Connector_CN801.jpg
Connector CN802 Pin-outs: PS64E550_Connector_CN802.jpg
==============
Voltages measured with multimeter/digital-oscilloscope at CN801/CN802 on the SMPS:
==============
STBY Voltage: Sits at ~5.3V and then drops to ~3.7V every time the power button is pressed (refer to scope data PS64E550_Main_connected_15V.bmp)
PS_ON: Sits at ~3.3V until I press the power button, it then drops to just above 0V for about 250mS before rising to ~3.9V for ~250mS and then returns to ~3.3V again (refer to scope data PS64E550_Main_connected_PS_ON.bmp which shows where I pressed the power button 3 times about 1.5 seconds apart).
D5.3V: Sits at 0V and then briefly rises to ~4.4V every time the power button is pressed (refer to scope data capture at PS64E550_Main_connected_D5_3V.bmp).
VS_ON: 0V
VS_CON: 0V, with some noise spikes of up to about 0.8V (pos. and neg.)
15V: peaks to ~12.6V when button pressed and then drops down towards 0V slowly until the power button is pressed again (refer to scope data capture at PS64E550_Main_connected_15V.bmp).
The GREEN LED light on the Logic board does NOT flash, even briefly.
===================
If I disconnect the cable between the SMPS and the Main Board and short the PS_ON to GND (Pin#1 to Pin#4), I can hear the relay clicking on and off with about a 1.5-second interval. While the relay is briefly on (<1 second) I can measure the following (measured at the CN801 cable):
STBY: short dip in voltage - to ~4.0V, then down to ~0.25V then up to ~1.6V for about 0.5secs and then a dip down to ~0.25V briefly before returning up to ~5.6V (refer to scope data PS64E550_Main_disconnected_STBY.bmp)
PS_ON: 0V (because it’s shorted to GND)
D5.3V: short peak in voltage - my scope shows it steps up to about 4.5V, a drop to ~4.0V for ~200mS and then ramps down more-or-less linearly to about 0V in the next 200mS, remaining low until the start of the next 1.5-second cycle (refer to scope data PS64E550_Main_disconnected_D5_3V.bmp)
15V: short peak in voltage: my scope shows it steps up to about 14V, a drop to about 12.5V for ~200mS and then ramps down more-or-less linearly to about 7.5V before the next 1.5-second cycle takes it up to about 14V again (refer to scope data PS64E550_Main_disconnected_15V.bmp).
VS_ON: 0.0V
VS_CON: 0.0V, but seems to have some spikes of 0.9V on this line (refer to scope data PS64E550_Main_disconnected_VS_CON.bmp).
==============
If I disconnect the Logic board from the SMPS and jumper the VS_ON to the D5.3V pin (with the Main board disconnected and PS_ON shorted to GND at CN801 as before), I seem to get all of the VS (220V), VA(55V) voltages ok.
I cannot find any circuit diagrams or start-up sequence info for this TV, and I’m not sure what is causing the start-up sequence to fall over in my case. Anyone have any hints as to what I can look at. Is it just that I’m not getting the correct supply to the Logic Board?
Regards,
Tiny68
Symptoms, when connected to mains, will display red STBY light on the front of the TV, but when I attempt to turn it on via the remote or the TV press-button it briefly goes off and then back on again (less than 1 second) back to a steady red STBY light (ie. no sequence of error flashes). When this happens there is the sound of a relay activating - sounds like a single click but based on my testing it looks like it closes and then opens very shortly afterwards.
Samsung 64” Plasma TV, Model: PS64E550D1MXXY.
SMPS Power Board: BN44-00515A
Logic Board: LJ41-10272A
Main Board: BN41-01802A
X-MAIN: LJ41-09452A
Y-MAIN: LJ41-09453A
Y-Buffers: LJ41-010270A, LJ41-010271A
Overview image of board layout: PS64E550_overview_annotated.jpg
Connector CN801 Pin-outs: PS64E550_Connector_CN801.jpg
Connector CN802 Pin-outs: PS64E550_Connector_CN802.jpg
==============
Voltages measured with multimeter/digital-oscilloscope at CN801/CN802 on the SMPS:
==============
STBY Voltage: Sits at ~5.3V and then drops to ~3.7V every time the power button is pressed (refer to scope data PS64E550_Main_connected_15V.bmp)
PS_ON: Sits at ~3.3V until I press the power button, it then drops to just above 0V for about 250mS before rising to ~3.9V for ~250mS and then returns to ~3.3V again (refer to scope data PS64E550_Main_connected_PS_ON.bmp which shows where I pressed the power button 3 times about 1.5 seconds apart).
D5.3V: Sits at 0V and then briefly rises to ~4.4V every time the power button is pressed (refer to scope data capture at PS64E550_Main_connected_D5_3V.bmp).
VS_ON: 0V
VS_CON: 0V, with some noise spikes of up to about 0.8V (pos. and neg.)
15V: peaks to ~12.6V when button pressed and then drops down towards 0V slowly until the power button is pressed again (refer to scope data capture at PS64E550_Main_connected_15V.bmp).
The GREEN LED light on the Logic board does NOT flash, even briefly.
===================
If I disconnect the cable between the SMPS and the Main Board and short the PS_ON to GND (Pin#1 to Pin#4), I can hear the relay clicking on and off with about a 1.5-second interval. While the relay is briefly on (<1 second) I can measure the following (measured at the CN801 cable):
STBY: short dip in voltage - to ~4.0V, then down to ~0.25V then up to ~1.6V for about 0.5secs and then a dip down to ~0.25V briefly before returning up to ~5.6V (refer to scope data PS64E550_Main_disconnected_STBY.bmp)
PS_ON: 0V (because it’s shorted to GND)
D5.3V: short peak in voltage - my scope shows it steps up to about 4.5V, a drop to ~4.0V for ~200mS and then ramps down more-or-less linearly to about 0V in the next 200mS, remaining low until the start of the next 1.5-second cycle (refer to scope data PS64E550_Main_disconnected_D5_3V.bmp)
15V: short peak in voltage: my scope shows it steps up to about 14V, a drop to about 12.5V for ~200mS and then ramps down more-or-less linearly to about 7.5V before the next 1.5-second cycle takes it up to about 14V again (refer to scope data PS64E550_Main_disconnected_15V.bmp).
VS_ON: 0.0V
VS_CON: 0.0V, but seems to have some spikes of 0.9V on this line (refer to scope data PS64E550_Main_disconnected_VS_CON.bmp).
==============
If I disconnect the Logic board from the SMPS and jumper the VS_ON to the D5.3V pin (with the Main board disconnected and PS_ON shorted to GND at CN801 as before), I seem to get all of the VS (220V), VA(55V) voltages ok.
I cannot find any circuit diagrams or start-up sequence info for this TV, and I’m not sure what is causing the start-up sequence to fall over in my case. Anyone have any hints as to what I can look at. Is it just that I’m not getting the correct supply to the Logic Board?
Regards,
Tiny68
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