Polaroid TLA-04011c Red Light on, no power on

[ryn0909]

Im new to this forum and im in need of some real help. Im trying to fix a friends tv for them. Its a polaroid tla-04011c. It wont power on, but the red indicator light comes on. ive tried the remote and tv power button and neither work. ive unplugged it and left it unplugged for 20+ hours, hoping it would reset, still nothing.
I am mechanically enclined and familiar with using and reading a multimeter. ive taken the back cover off of the tv and thoroughly inspected the main board and power board looking for bad caps or something burnt. all the caps LOOK good, none bulging or exploded on either main or power board. However, there is one concern i have and its on the power board. to me it looks like something may have burnt, but i dont see any secondary indicators on any of the components near it. Attached are 2 pictures of what im talking about.

Also, i did some checks on the power board with my multimeter and this is what ive got....

CN3 (13pin header) 8 pins used
pin 3 Vsb- 5vdc
4 v1- 5vdc
5 v1- 5vdc
6 GND
7 GND
8 GND
12 v2 0vdc
13 remote 0vdc


and C7 (Main Cap) 163vdc


i hope this makes sense to whoever can help. Any assistance is greatly appreciated thank you

[daimoku]

Re: Polaroid TLA-04011c Red Light on, no power on

Looks like the power IC may be fried. I can't make out the part number from the picture; but, you can read the part number from the top of the IC and google it for a datasheet. The datasheet will give you the pinout for the IC and you can take a reading accordingly.

Make sure you test the "upstream" components to identify what fried the IC.

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

the part # for that ic is a6252m. im downloading the data sheet now, and ill do the checks on it and post my findings.

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

ok so do i check it in-circut or out of circut? and what checks do i do lol i guess thats an important thing to know lol

[PlainBill]

Re: Polaroid TLA-04011c Red Light on, no power on

By the location, that IC is the SMPS controller for the standby supply. If the any voltage is present, that IC is working. Notice it's only rated for 20 watts - fine for a standby supply, but not for the main supply.

What would be helpful is three more pictures. The first would be an over-all shot of the TV, showing the relationship of the various boards. Then two pictures of the power supply, one of the top, one of the bottom. I'm particularly interested in any legends around the output connectors.

PlainBill

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

ill get right on it thank you very much. ill be posting the pics here in just a few minutes. thanx again

[daimoku]

Re: Polaroid TLA-04011c Red Light on, no power on

By the way, the filter cap reading looks good.

To test the power IC:
Locate the VCC pin from the datasheet. Place the red probe on the VCC pin and the black probe to HOT ground (filter cap negative terminal). Switch the power on and you should get a reading around 16-20 Volts


Listen to Plainbill - he's the guru

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

k thanx alot, will do. im takin the pics now

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

ok here are the pics. also i did the check on the ic and i got 16.45vdc

[PlainBill]

Re: Polaroid TLA-04011c Red Light on, no power on

ok here are the pics. also i did the check on the ic and i got 16.45vdc

Aughhh!!! Horrible pictures.

On CN2, what voltages do you see at pins B, A, and any pin labeled V3? Measure from any pin labeled GND. Do any of those pins change voltage when you press the power button?

On CN3, what voltages to you see at pins B, A, Vsb, any pin labeled V1, any pin labeled V2, Remote? Again, measure from any pin labeled Gnd. Also, do any of those pins change voltage when you press the power button?

PlainBill

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

sorry for the bad pics, let me do the checks and ill get back to ya in a few

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

here is a modified version of the pic with the connectors

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

ok heres what i got....
(CN3) pin B- 0vdc A- 0vdc Vsb- 5vdc V1- 5vdc V2- 0vdc REMOTE- 0vdc

(CN2) pin B- 0vdc A- 0vdc V3- 0vdc

and there is no change when i press the power button

[PlainBill]

Re: Polaroid TLA-04011c Red Light on, no power on

ok heres what i got....
(CN3) pin B- 0vdc A- 0vdc Vsb- 5vdc V1- 5vdc V2- 0vdc REMOTE- 0vdc

(CN2) pin B- 0vdc A- 0vdc V3- 0vdc

and there is no change when i press the power button

Please verify that are no other output connectors on the power supply. I am specifically interested in a pin labeled PSON or the equivalent.

A quick background: Virtually every LCD / Plasma TV uses the same general design for the power supply. It is a dual section supply with a standby section that is always on, and a main section that that is switched on and off as the TV is switched on and off.

The main board on the TV has a standby processor that monitors the remote input and the keypad. When the power button is pressed, it performs a few tests, then turns the main supply on via a control line which is usually labeled PSON, On/Off, etc.

Assuming there is no additional connection to the main board, the problem is the power supply is not being commanded on. That is a problem with the main board.

OOps!!! IS there a separate legend identifying the pinout of the connector behind CN2? (Repeat complaint about the poor quality of the pictures omitted.)

PlainBill

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

there are no other output connectors on the power board. and there are no pins labeled PSON.


threre is no legend identifying the connector behind CN2, which is labeled CN4

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

threre is no legend identifying the connector behind CN2, which is labeled CN4


so what should i do ?

[PlainBill]

Re: Polaroid TLA-04011c Red Light on, no power on

threre is no legend identifying the connector behind CN2, which is labeled CN4


so what should i do ?

Your call. There are several main boards for sale on eBay (make sure the part numbers match), and a complete TV with a damaged screen.

PlainBill

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

ok thank you very much for all your help.... i really appreciate it. one quick question... i looked on ebay and found a board thats a 200-107-gt321xa-Bh mine is a 200-107-gt321xa-Ah do you know if that would work or what the difference would be ??

[crtfool]

Re: Polaroid TLA-04011c Red Light on, no power on

I have a different model Polaroid that had the exact same problem - the main control board was faulty.

I recommend that you buy the board on eBay, and do not deal with Polaroid - their customer service department is very nasty, and they are unwilling to sell you the part that you need. They will only sell you a complete control box that is refurbished with absolutely no warranty unless they send a technician to install it for an extra charge! They also want the defective control box back.

[ryn0909]

Re: Polaroid TLA-04011c Red Light on, no power on

lovely.... lol i was probing the caps with the multimeter in diode mode, checking to see if i could find any that had a direct short but founf none. HOWEVER, i did notice that all the 16v 220uF caps would measure around the same except for 2 of them. those 2 would go to infinite while none of the others would. Is that a sign of a bad cap??