Proscan PLD3283D has Standby but Won't Turn On

[barkster]

I've been testing the mainboard which is the only board on the tv and haven't found any issues as to why this tv won't turn on. It has standby power and I can't figure out how to manually turn it on by jumpering as I don't know what pin it is. I've tested the diodes, a few caps and regulators and didn't see any issues. Here are pics and voltages on pins.


GND - 0
K7/N - 0
K6/P - 3.3
K5/M - 3.3
K4/V- - 3.3
K3/V+ - 3.3
K2/C - 3.3
K1/C+ - 3.3
K0/S - 3.3
GND - 0
IR - 4.78
GRN - 0
RED - 2.75
5V - 5

[budm]

Re: Proscan PLD3283D has Standby but Won't Turn On

I see about 4 LDO regulator ICs, UL1, 41, 51, and UT1 (this one may not be IC, not sure) which you should test the Voltages on all 3 pins.
Read the link below on how to test and report the readings in the FORMAT we can easily understand.

[barkster]

Re: Proscan PLD3283D has Standby but Won't Turn On

Thanks, I checked them for short but haven't check for voltage. Will do tonight and report back. Thanks

[barkster]

Re: Proscan PLD3283D has Standby but Won't Turn On

OK here we go:

UL41:
pin1 - 1.25
pin2 - 2.50
pin3 - 5

UT1:
pin1 - 0
pin2 - 3.3
pin3 - 5

UL1:
pin1 - 0
pin2 - 3.3
pin3 - 5

UL51:
pin1 - .5
pin2 - 1.8
pin3 - 4.3

Not sure if this shows any signs of defective part but do you know how to manually power on this thing? I didn't recognize the power on pin on the board

Thanks

[barkster]

Re: Proscan PLD3283D has Standby but Won't Turn On

also when I press the power button on tv this is voltage changes on pins

K6/P - 0
K5/M - 1.4

[barkster]

Re: Proscan PLD3283D has Standby but Won't Turn On

anyone know what UL51 is, it's marked at 1117B AD B72V I can't find datasheet on it.

[jetadm123]

Re: Proscan PLD3283D has Standby but Won't Turn On

anyone know what UL51 is, it's marked at 1117B AD B72V I can't find datasheet on it.

It's an adjustable voltage regulator. Just Google "1117 voltage regulator" for datasheet.

[budm]

Re: Proscan PLD3283D has Standby but Won't Turn On

https://www.badcaps.net/forum/showpo...99&postcount=8
https://www.badcaps.net/forum/showth...999#post300999

The readings on post 4 are fine.
UL51 is an adjustable reg, pin 1 of 0.50V + Vref of 1.25V = Vout of 1.75V (+/- 3%)

[barkster]

Re: Proscan PLD3283D has Standby but Won't Turn On

yeah I found the datasheet for others but the AD B72V I couldn't find and threw me off. Any other suggestions? Anyone know how to force this set on with the pin outs listed. I think the power button is working because pin K6/P goes low when I push it so I think I can rule that out but I'm willing to try anything at this point.