Model: Samsung TC-P60ST60 Plasma TV
SM Note:
When reviewing the Service Manual, both the S60 and ST60 series TV’s are covered. Don't confuse the S60 diagrams with the (appropriate for this TV) ST60 diagrams.
Symptoms:
TV won’t power on; no Red LED Standby Indicator (and no blink codes).
Measurements in Standby (measured on P6, bottom left of Power Supply):
P6-1 (Panel_Main_ON) = 0v
P6-2 (S1) = 0v
P6-3 (S2) = 0v
P6-4 (STB5V_ON) = 0.173V
P6-5 (STB5V) = 4.49V
P6-6 (F15V_ON) = 2.79V
P6-7 (GND) = n/a
P6-8 (GND) = n/a
P6-9 (F15V) = 15.72V
P6-10 (F15V) = 15.72V
P6-11 (GND) = n/a
P6-12 (P15V) = 0V
P6-13 (GND) = n/a
P6-14 (15V_S) = 15.72V
Observations:
Fuses are good, caps are good (not bulged, all tested good with in-circuit Capacitance meter).
Power supply is producing STB5V, mainboard is producing 3.3V, other necessary voltages are present. STB5V reads 4.49V which seems to be off more than a bit – is this too low to operate properly?
Issue seems to be related to the fact that the secondary 15V supplies should come on for 8-11 seconds, then be turned off while in standby - on this TV they are on all the time.
When the set is plugged in, I hear one click of the relay, there should be two clicks heard (1 as the 15V supplies are instructed to turn on, then a second click when those same supplies are shut off again. The Troubleshooting flowchart on Slide 86 of the Service Manual (“SM” - attached) says that if only 1 click is heard, the Power Supply (P Board) should be replaced.
However, the mainboard is what tells the PS to turn on the secondary supplies via the F_STBY_ON command being raised for approximately 8-11 seconds (Slide 21 of the SM) during which time the secondary supplies are turned on, then off again. On this set, F_STBY_ON is always present on Connector P6-Pin 6 so the Power Supply seems to be doing what it is instructed to do by the mainboard processor (IC8000).
I’d like to determine what next steps I can take to narrow the problem down to the either the Power Supply or Mainboard. I don’t really want to just shotgun it by buying boards until it works. I'd also prefer to fix the problem if it's a Power Supply issue rather than swapping boards. If it is the Mainboard (A board), then I'd look at fixing or replacing the board since some of the components are beyond my repair facilities.
I did read somewhere that one person said his TV with same exact symptoms turned out to be the IR sensor board, I guess that’s another possibility since the Standby LED is not on.
SM Note:
When reviewing the Service Manual, both the S60 and ST60 series TV’s are covered. Don't confuse the S60 diagrams with the (appropriate for this TV) ST60 diagrams.
Symptoms:
TV won’t power on; no Red LED Standby Indicator (and no blink codes).
Measurements in Standby (measured on P6, bottom left of Power Supply):
P6-1 (Panel_Main_ON) = 0v
P6-2 (S1) = 0v
P6-3 (S2) = 0v
P6-4 (STB5V_ON) = 0.173V
P6-5 (STB5V) = 4.49V
P6-6 (F15V_ON) = 2.79V
P6-7 (GND) = n/a
P6-8 (GND) = n/a
P6-9 (F15V) = 15.72V
P6-10 (F15V) = 15.72V
P6-11 (GND) = n/a
P6-12 (P15V) = 0V
P6-13 (GND) = n/a
P6-14 (15V_S) = 15.72V
Observations:
Fuses are good, caps are good (not bulged, all tested good with in-circuit Capacitance meter).
Power supply is producing STB5V, mainboard is producing 3.3V, other necessary voltages are present. STB5V reads 4.49V which seems to be off more than a bit – is this too low to operate properly?
Issue seems to be related to the fact that the secondary 15V supplies should come on for 8-11 seconds, then be turned off while in standby - on this TV they are on all the time.
When the set is plugged in, I hear one click of the relay, there should be two clicks heard (1 as the 15V supplies are instructed to turn on, then a second click when those same supplies are shut off again. The Troubleshooting flowchart on Slide 86 of the Service Manual (“SM” - attached) says that if only 1 click is heard, the Power Supply (P Board) should be replaced.
However, the mainboard is what tells the PS to turn on the secondary supplies via the F_STBY_ON command being raised for approximately 8-11 seconds (Slide 21 of the SM) during which time the secondary supplies are turned on, then off again. On this set, F_STBY_ON is always present on Connector P6-Pin 6 so the Power Supply seems to be doing what it is instructed to do by the mainboard processor (IC8000).
I’d like to determine what next steps I can take to narrow the problem down to the either the Power Supply or Mainboard. I don’t really want to just shotgun it by buying boards until it works. I'd also prefer to fix the problem if it's a Power Supply issue rather than swapping boards. If it is the Mainboard (A board), then I'd look at fixing or replacing the board since some of the components are beyond my repair facilities.
I did read somewhere that one person said his TV with same exact symptoms turned out to be the IR sensor board, I guess that’s another possibility since the Standby LED is not on.
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