PSU model#: 514C5006M33A &/or TV5006-ZC02-02
TV model#: 1000012585 (55" Onn Roku TV)

I managed to find a schematic for it but it's practically useless, IMO. The circuit is all broken up in the diagram & the labels are incorrect (for instance, it doesn't label any 5V lines. Everything's labelled 12V!?)

I already replaced the fuse and (I believe) the MOSFET. (In diagram, the mosfet is labelled 70R600. The one on the board is 07N60C3. I remember, I removed the mosfet from circuit & tested it. I just can't recall whether I replaced it).

Anyway, as the title said...the 12V pins on the power supply measure 12V, but the 5V & 5VSB pins have no voltage.
I have some experience repairing circuits.. But not a great deal. I'm at a loss when it comes to how the standby voltage can be missing, while the 12V lines are powered. That's the case, even without shorting PS-ON & STBY.

Here's the diagram:photos of the front & back of the board:


There are a lot of versions of this board, BTW. It seems, the diagram isn't for this EXACT version. (2nd page of diagram, which i didnt include, has 2 LED connectors, while this board has one. That's also why I'm not sure whether I swapped out the MOSFET. The 07N60C3 may have came on the board. I stopped messing with it for a few months. That's why I can't remember.

Since the labels are in white on the board, it's hard to see (in the pic) the pin assignments. Since the pins in the diagram are incorrectly labeled, here's the correct pin layout:
Starting at pin directly under the 3 pin connector:
13)GND
12)ADJ
11)ON/BK
10)+5V
9)ON/OFF
8) 5VSB
7)+5V
6) +5V
5) GND
4) GND
3)GND
2) +12V
1) +12V

Any thoughts are definitely appreciated!!

 

It may be a common pcb for more than 1 type of psu, yours caters to only 12 volts. Others may cater to both 12 and 5. The board shows a lot of components are not wired.

 

OMG. I'm SO glad you posted this response!
I had no idea a TV could use 12V alone. I've been wondering how the heck the 5VSB could power the TV on.
Looking at the board, there are no components connecting the 5VSB pin to the rest of the circuit. The trace leading away from the pin just ends. There are spots for components..but it lacks any components in that area (to tie it to any circuit). Idk if that makes sense.

I guess i should try putting the TV back together & see if it works. Still, I can't comprehend how the TV is supposed to power off and on without a standby voltage. Maybe the main board controls that?

 

MANY consumer product PC boards include portions that are not populated! The reason is that it is very cost-effective to design a single PCB for a whole product line that includes different requirements. The cost of each tooling variation is quite a bit.

 

MisterBill2- I was aware many PCBs were like that. What I didn't know was that a TV PSU might not even produce standby voltage. I honestly had no clue. That threw me for a loop!

I need to stop being lazy, put the tv back together & see if it works. I really hope so! But I'll feel so stupid, if so. Since I literally stopped messing with it for months, thinking something was still wrong with it (from the lack of STBY voltage).

 

I just thought....I should probably mention... there's NO voltage on ANY other pins (to that long connector) except the bottom two (which have just over 12V). There's no voltage at all on the STBY pin.

Were you guys saying there shouldn't be ANY voltage at all for standby? Or were you saying it uses 12V for standby?

I wanted to make sure, before I waste time & energy putting the thing back together. I know i mentioned being lazy.. But the truth is, I'm practically bedridden due to an illness that keeps me chronically fatigued. I have to be very choosey about what I choose to spend my very limited energy supply doing.

I know i need to figure out whether I can get this TV working ASAP, though. I need to know if my daughter should ask for a tv for Christmas. Her grandmother on her dad's side wants her Christmas list today. My daughter's been sleeping in my bed most of the time, because there's no TV in her room.

I actually tried purchasing a replacement power supply for this TV over a month ago. I got acammed, though. BTW, never purchase anything from tvpartsmarket.com! That's the site I was scammed by.

 

It is entirely possible that the control to make the supply function is that line marked ON/OFF (pin #9) so it may not come on until things are assembled.
That brings up a question of why you took it apart, and what did you fix. Possibly that has been mentioned already, I may have missed it.

 

To begin with, I replaced the fuse and MOSFET. After that, the 12V pins (2 bottom pins) measure roughly 12.6V. I'd been under the assumption that something was still wrong, since the pin labeled 5VSB had no voltage.
But... then i saw that response on here, saying me this particular PSU variation only caters to 12V. (They mentioned that other variations of this board layout produce both 5V & 12, but not this one.)
At first, I thought they meant this TV doesn't use STBY. Then later, I started thinking, maybe they meant the standby is 12V on this board.

I'm still not sure. Have you heard of TVs not using standby? I can't really comprehend how that'd work.. unless the whole TV turns off, with no standby light or anything. Idk. I'm just having major brain fog & can't really even get my mind to cooperate to think hard enough to imagine how/if TV's could function without STBY.

I took the TV apart because it wasn't working. It came from the side of the road. Lol. I've repaired a couple other TVs in the past. Those were my family's TVs that just stopped working. In both earlier cases, the issue was the MOSFET (&fuse) on the power supply. A few years ago, I learned a little about diagnosing circuits. I've pretty much only had to mess with the primary side when dealing with SMPSs, though. The other TVs had standby. After noticing that they had shorted mosfets & replacing those, the PSUs had STBY voltage. So i didn't need to probe any farther.

I just measured each of the pins again. There's 0V exactly on every pin except the bottom 2. That goes for the LED- & LED+, too. I may not have measured the LED pins correctly. I feel like i remember reading somewhere that you aren't supposed to measure the LED voltage using regular ground. Instead, you need to use the LED ground pin as reference. So, that's what i did. I expect, there was no voltage because the PSU should have been off. I only had the PSU plugged in. No pins shorted together or main board connected. (Not like shorting pins would make a difference, anyway..since there's no voltage on PS-ON or 5VSB.)

I guess, what i mainly want to know is...is it possible for certain TVs to be designed to work without the PSU producing STBY, at all?

I also wanna point out ... Looking at the power supply...if you follow the trace that leads to the 5VSB pin, it doesn't connect to the circuit.. Not on the layer I can see anyway. The other side of the board lacks components in that area, too. So, it does seem like the PSU doesn't use STBY whatsoever. I'd just like to know if that's possible before I get all the cables, boards and put it all back together.

 

Update...in case it's helpful for someone in the future:

I went ahead and connected the power board and the main board last night. I didn't attach T-con & Wi-Fi boards or screen... Just the main board with the IR/power button connector attached.

Guess what happened ?! The red standby button lit up!
I tapped the power button on the IR board & the red light started blinking. Measured voltage at ON/OFF pin (can't remember whether that was before or after I pressed power button.) but the voltage was 3V (& some change).

So...it seems, I already fixed the issue mts ago, before I got annoyed and nearly left the TV for dead! Idk if you read the part where I said I *tried* to purchase a power board for this TV a while back (but got scammed). I'm actually kinda glad that happened now.. Since I didn't even need the power board.

To sum things up, I'm actually glad this happened. It taught me something I would have never figured out otherwise. It's actually all thanks to Ramussons, the person on this forum who informed me that some TV PSUs don't directly output standby voltage.

I need to clean the screen up really well before I put it all back together. But from the looks of it, the TV is actually gonna work! I'm so excited!