Sanyo CE32LD47-B flashing standby light

[selldoor]

Re: Sanyo CE32LD47-B flashing standby light

good picture - can you do the back if there is enough light left

[blib]

Re: Sanyo CE32LD47-B flashing standby light

On the main board its not possible to work out if I have short to ground as cant tell what pins go to ground.Fuse on inverter is OK.I really do not know which board is faulty as I thought that the power supply would require a Ps-on voltage from the main pcb for the 24volt rail to switch on.

[ben7]

Re: Sanyo CE32LD47-B flashing standby light

ok,seems like you have a short on the mainboard

Im thinking the same.

[multimeter]

Re: Sanyo CE32LD47-B flashing standby light

ok,seems like you have a short on the mainboard,which is dragging the voltages down,shorts tend to cut the voltages right off,a failing component will "alter" the voltage ,prob lower it.

take the main board out ,and resistance check every pin to cold ground,apart from the ground pins,you should have very high resistance in the high k ohm range, on the other pins to ground,i think you will find a shorted rail on that mainboard,the psu standby voltage,will be waiting for the control signal to switch on the rest of the psu from the mainboard,some will have a bl_on signal also coming from the main board,to switch the inverter on,prob a 3.3v signal,a close up of the mainboard would be handy?

[selldoor]

Re: Sanyo CE32LD47-B flashing standby light

Can you do pictures of the main board?

[blib]

Re: Sanyo CE32LD47-B flashing standby light

The esr of the four elecrolytics on the primary side all check out as do all the others as well.Looking at the circuit there seems to be two switch smps one for +3.3stby and +5stby and the main smps each one controlled by a tny266 ic.The standby smps is working ok its the main one thats powering down.
I have just disconnected the plug that supplies the main board and found that the 24volt ,12volt lines all stay up so maybe i have a main board fault or could it be the main board is not getting a back light on signal and switching the power supply down?

[selldoor]

Re: Sanyo CE32LD47-B flashing standby light

Did you check the fuse on the inverter board in case it is shutting down because the inverter is off.

[multimeter]

Re: Sanyo CE32LD47-B flashing standby light

can you esr the 2 caps next to the large transformer?,just there, is a 8 pin chip,one of those caps should go to vcc on that chip,it will be the startup cap,if you dont have an esr meter,find the datasheet for that chip,find the vcc pin,note the voltage,power the tv on ,measure that voltage on vcc,this does seem to be a startup cap failiure,beacause of the constant voltage up voltage down voltage up etc,i think there should be around 22v going to vcc,not sure tho

[blib]

Re: Sanyo CE32LD47-B flashing standby light

Worked out the pins and done some more checks and I have +5vstby on pin 14 and +3.3stby on pins 15 and 16 of PL816 permanently. All the other voltages come up for about 5 seconds then die then come up again then die permanently leaving the flashing front led.

[blib]

Re: Sanyo CE32LD47-B flashing standby light

Ok got the schematic now thanks

[blib]

Re: Sanyo CE32LD47-B flashing standby light

Tom, The link to the schematic seems to be broken .

[vinceroger69]

Re: Sanyo CE32LD47-B flashing standby light

maybe worth checking this thread out
https://www.badcaps.net/forum/showthread.php?t=16418

[tom66]

Re: Sanyo CE32LD47-B flashing standby light

Schematic
http://tgohome.com/ServiceManuals/Vestel/Vestel_17PW26_[SCH].pdf

Can you determine which pin is which now? Of interest are the 5VSTBY and 3.3VSTBY pins, as well as ST_BY and SW_SWITCH.

[blib]

Re: Sanyo CE32LD47-B flashing standby light

Hi Tom
There are no markings on the pcbs showing P-on but
referring to my first pic showing the socket connecting to the main if pin 1 is top left and pin 15 is bottom right then voltages are as follows.
Pin 1= 0.00v
Pin 2= 8.45- 8.57v (fluctuates)
Pin 3=2.92v
Pin 4= 0.00v
Pin 5= 0.00v
Pin 6= 1.75v
Pin 7=5.04v
Pin 8=3.42v
Pin 9=0.1v
Pin 10=0.1v
Pin 11=0.1v
Pin 12=0.1v
Pin 13=0.1v
Pin 14=0.1v
Pin 15=NC
Pin 16=0.09
Pin 17=0.00
Pin 18=0.59
Pin 19=0.59
Pin 20=0.59
Pin 21=3.43
Pin 22=0.00
Pin 23=1.75
Pin 24=0.00
Pin 25=0.00
Pin 26=0.00
Pin 27=0.00
Pin 28=NC

[ben7]

Re: Sanyo CE32LD47-B flashing standby light

Are there any other voltage rails on the output? It sounds like there could be a short, or a rail is not reading the correct voltage.

[tom66]

Re: Sanyo CE32LD47-B flashing standby light

Sounds like a main board issue more than anything, check PS ON pin.

[selldoor]

Re: Sanyo CE32LD47-B flashing standby light

Can you check the joints marked with a magnifier and resolder any you think are bad- Its hard to tell on a picture but a few look to have cracks/rings.

[blib]

Re: Sanyo CE32LD47-B flashing standby light

9.5Kohms

[multimeter]

Re: Sanyo CE32LD47-B flashing standby light

Thanks for the replies.Pin 12 to ground is 8.9Kohms with inverter connected.I have found a short between pins 1 and 3 of IC831 with pin 3 disconneced but I cant identify the device.

8.9kOhm is saying that rail isnt shorted,what is the reading with inverter disconnected?

[blib]

Re: Sanyo CE32LD47-B flashing standby light

IC831 turned out to be a red herring.I lifted it off the board and i can see now its just a diode with only two pins connected to the pcb and it reads OK.Cant see any bad joints and posting a better picture of the print side.Bye the way back light does not flash at start up.
Does any one know if this power supply will work in isolation and if not is there a way to test it? I still think it might be shutting down because of no voltage on pin 12 of PL802 which might be the back light on signal.Just dont want to get another power supply and find i have the same problem.