Sceptre X32 Power Supply Diagnosis

[tzantzai]

Re: Sceptre X32 Power Supply Diagnosis

Posted in error

[urfavtech]

Re: Sceptre X32 Power Supply Diagnosis

@budm

Hello, working on my 2nd TV now which is also a Sceptre X32 model

Symptoms: Ultimately, blue power light comes on and shows nothing on screen.
Intermittently, blue power light comes on, SCEPTRE logo appears, then
disappears, and blue light goes off.

I read over this thread, and although my tv is same model, my power board ( ay118p-4hf01 ) looks slightly different from the one in Version 7's pictures. Was wondering if it you (budm) or anyone else could point me in the right direction.

Thanks,
Cory

[budm]

Re: Sceptre X32 Power Supply Diagnosis

http://assets.shopjimmy.com/media/ca...f01-bottom.jpg

As you can see, at the bottom side of the there are labels for each pin of the connectors.
Take the Voltage readings of each pin when the TV is plugged in but not turn on, and then when the power switch is activated. Please make sure to label each pin name and voltage for each pin.

[urfavtech]

Re: Sceptre X32 Power Supply Diagnosis

Ok here are the results when OFF

GND = 0
GND = 0
GND = 0
GND = 0
24v = .011
24v = .010
24v = .010
24v = .009

GND = 0
GND = 0
24v = 0
24v = 0

12v = blank
12v = .004
GND = 0
GND = 0
GND = 0
5v = blank
5v = .015
5v = 5.25
5v = 0
5v = .016
5v = .016
GND = blank
GND = blank
_________________________________________

here are the results when ON

GND = 0
GND = 0
GND = 0
GND = 0
24v = 24
24v = 24
24v = 24
24v = 24

GND = 0
GND = 0
24v = 24
24v = 24

12v = blank
12v = 12
GND = 0
GND = 0
GND = 0
5v = blank
5v = 5.25
5v = 5.25
5v = 4.45
5v = 5.23
5v = 5.23
GND = blank
GND = blank

So now that i know where the label is, it seems as though the power supply should be ok, am I right? If so, next step main board?

I added some images of main board just in case. I did check the 1117 voltage regulators, and one on far left of main board reads 5+ volts, and as I work my way to the right side of board, the last 3 i believe read 2 volts or lower... not sure what step to take

[budm]

Re: Sceptre X32 Power Supply Diagnosis

There is one pin with ON/OFF (PS_ON) that you did not list, but it must be OK otherwise you will not have the switched 5V, 12V, and 24V.
So the power supply is OK.
So now we to look for the bl_on signal on the inverter board to connector to see if it is present to turn on the backlights.

[urfavtech]

Re: Sceptre X32 Power Supply Diagnosis

Here is the image of connector from power supply board to inverter.

The 2 leads at the top of the picture go to control board.

The voltage stays steady when on, a few times the back light came on, but then whole tv went off including the power lights, when that happens all voltage is lost so im assuming the tv powered down completely, but when I get it to stay on, the back light is not lit and the blue power light does stay on. When blue light is on the voltage stays steady on power board and inverter.

Not sure if there is an actual label for bl_on, did not see anything of the sort.

Thanks,
Cory

[budm]

Re: Sceptre X32 Power Supply Diagnosis

"The voltage stays steady when on, a few times the back light came on, but then whole tv went off including the power lights, when that happens all voltage is lost so im assuming the tv powered down completely, but when I get it to stay on, the back light is not lit and the blue power light does stay on. When blue light is on the voltage stays steady on power board and inverter." To me that sounds like the main board malfunction.
Can I see the whole picture of the inverter board? Can you get to the LCD panel model number sticker so we can get the pinout of the inverter board, any model numbers printed on the inverter board?

[RJARRRPCGP]

Re: Sceptre X32 Power Supply Diagnosis

I saw a "KM" cap, highly likely a bad cap, even without bulging or leaking at the base. Notorious for being real out-of-spec when looking good on the outside!

[urfavtech]

Re: Sceptre X32 Power Supply Diagnosis

I will get this information tonight after work

Thanks

[blavergne]

Re: Sceptre X32 Power Supply Diagnosis

So I am having trouble getting any signal of any kind to my Sceptre X322BV-HD. The capacitors don't seem to be bulging (I have attached a few pictures of the boards for reference). Curious if any one has a good suggestion of where to start before I waist too much time Sodering in capacitors that don't need to be fixed.

I bought the replacement capacitors from Amazon:
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

As well as a beginner sodering kit:
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

Those are the materials I have for now.

Feel free to check the pics of the boards.

[budm]

Re: Sceptre X32 Power Supply Diagnosis

@blavegne, please start a new thread since your TV is not the same model as OP, it will confuse people and hard for me and others to keep track of which models we are referring to.

[urfavtech]

Re: Sceptre X32 Power Supply Diagnosis

Sorry for the delay, here is some photos of the inverter board and a sticker that was on the metal backing of the LCD screen.

Also i barely seen it, but there was an engraving in the metal backing as below:

20121002N
HV320WXC C01 0

I hope this helps, thats as close as i can get to the inverter board and still keep it all in the picture, let me know if you need any close ups and if that is the correct LCD label, or if I have to remove all that metal backing.

Thanks,

[blavergne]

Re: Sceptre X32 Power Supply Diagnosis

My TV is an X32 Sceptre, just specific model X322BV-HD. Everyone on this post is talking about slight variations and different board configs.

Thanks

[budm]

Re: Sceptre X32 Power Supply Diagnosis

I cannot find the spec sheet of the panel (HV320WXC-100) to get the pinout of the inverter board.
One of the pin will be ON/OFF, another one will be for dimming.
Since one pin has 5V on it already then what we can do is to force the other pin using 100~500 Ohms resistor between that pin with 0V and 5VSTBY pin but you will have disconnect that wire first so the voltage will not back feed to the main board.

[doctor j]

Re: Sceptre X32 Power Supply Diagnosis

Thanks for the valuable information. I scored "free" TV with no picture problem (similar to topic starter).
There were some interesting points:
In addition to bad caps (in green) one more capacitor 820u F 25V was bulging as well (purple box). I used 1000 uF cap to replace and it did not work; 680 uF cap is working (original cap is in order)
Also one of the 4 redlined caps 100 uF, 50V had only 67 uF capacity so I changed it out as well.
The TV works now!!
It is a very cool thing to revive TVs (I am beginner in this field:, I am fixing cars) and to learn something new
Now I am collecting old bards to de-solder caps
Fixed so far:
48 (?) inch Samsung HDTV for my relatives (they taught me about bad caps, but did not have soldering skills)
19 inch Sanyo
HP PC (bad caps on motherboard)
And now Sceptre X32 I am watching it as I am typing this
Thank you all of you for shared knowledge!!

[urfavtech]

Re: Sceptre X32 Power Supply Diagnosis

I think I found the pinout spec sheet, tell me if this is what you need, i will also provide source link.

http://wenku.baidu.com/view/58e83ad6...aa811da98.html

EDIT: I found the Bl_on, here is what happens:
scenerio 1: if backlight initially comes on, I have 5.2v on BL_on pin, when backlight goes out even though the blue power light is still on, BL_ON drops to 0
scenerio 2: if no backlight, just blue light, BL_ON has 0v

[budm]

Re: Sceptre X32 Power Supply Diagnosis

Oooo, how did you find that free info? panel-look want me to signup to get the PDF.
So pin 12 is the BL_ON.
So what we can do is to force on the inverter, right now it looks like the command ON signal from the main board drops out, the IMPORTANT thing to do is to disconnect the wire from pin 12 first, turn on the TV then connect a 100~500 Ohms resistor between pin 12 and the 5VSTBY to force on the backlights, the backlights should come on and turn on as long as the resistor is in place.

[urfavtech]

Re: Sceptre X32 Power Supply Diagnosis

do i just hold the resistor in place with hand or is there a technique? the only way i can disconnect that line, is by unplugging the whole connector on main board which has pin 12 and 14 going to it, is that ok?

[budm]

Re: Sceptre X32 Power Supply Diagnosis

It is best to solder since you do not want to slip the connection and accidentally blow some thing up, you can solder one end of the resistor to the 5VSTBY and solder a small piece of wire to the other end of the resistor, then solder another small wire to pin 12. After turning on the TV then you will touch the exposed ends of the two wires together to complete the circuit.
You can cut the wire but make it long enough for you to be able to splice it back together, we need to have the plug in place for testing.
Be real careful since you are working on the inverter board which has a couple 1000V!

[urfavtech]

Re: Sceptre X32 Power Supply Diagnosis

ok so 100~500 ohms resistor one end on the 5vstby on power board, other end on pin 12 on inverter. ok first time for everything lol