PSU TEST ON TV7001-ZC02-01 BOARD

[itronic]

Just reaching out. Anyone know how to test PSU without main board . Trying to test backlights.

[itronic]

Voltages on PSU board with main board and led disconnected:

3 large main caps - 380v DC

CON201

GND
ADJ -
BK -
+5V - Not Connected
PSON -
+5VSB - Not Connected
NC - Not Connected
ND - Not Connected
GND
GND
GND
+12V - 11v
+12V - 11v

[nomoresonys]

Brand and full model of tv?

[itronic]

ONN 70 INCH. Model 100068378

[nomoresonys]

With everything hooked up as normal, what voltages do you get on PSON and BK, test in standby[tv plugged in but off] then keeping probes where they are turn tv on then what are they, other words do the voltages change/toggle when you do it and are they steady?

[itronic]

First test:

Leads placement:
black on frame ground
red on bk connection
voltage is .1vdc in standyby

red lead on pson
voltage is 2.0vdc to 2.5vdc it flucuates in standby
pushing power switch they are no change in any voltage


Second test:

Leads placement:
black on bk
red on pson
voltage is 2.0vdc to 2.5vdc. it flucuates. in standby
pushing power switch they are no change in any voltage

[nomoresonys]

No, for second test it is black on frame ground red on BK.

[itronic]

Leads placement:
black on frame ground
red on BK connection
voltage is .1vdc in standyby
pushing power switch they are no change in any voltage

[nomoresonys]

Check the diodes on top of the board, looks like there's six, diode checking is done with tv unplugged from power. Another easy test, with everything hooked up heat the electrolytic caps with a hairdryer for a couple minutes then try turning on tv, see if there's any difference if only for a bit.

[nomoresonys]

Also check those two resistors, maybe switch out EC201 right by the connector if you have one handy and no way to test the caps.

[nomoresonys]

Quite often when you have those fluctuating voltages it's because of a faulty capacitor.

[itronic]

Thanks . Already replaced the LED Capacitor (EC210).Will test further

[itronic]

Results from following test:

4 diodes- D203-D206= .398 they all read same. good
2 blue caps :C338=202PF(replaced with 221pf) good now. C133= 102PF (GOOD)
EC210- 5UF REPLACED- READING IS 10UF NOW.
EC201 - (448UF) REPLACED -READING IS 470UF NOW.

VOLTAGE READINGS.
BEFORE CHANGED THE 4 DIODES READING:
D203 =5DCV
D206= 5DCV
D205=320DCV
D204=320DCV


VOLTAGE READINGS.
AFTER PARTS REPLACED, THE 4 DIODES READING:
D203 =25-45DCV- FLUCTUATING
D206= 25-45DCV FLUCTUATING
D205=320DCV
D204=320DCV

Leads placement:

black on frame ground
red on bk connection
voltage is .1vdc in standyby
pushing power switch they are no change in any voltage

red lead on pson
voltage is 2.3vdc to 2.5vdc it flucuates in standby but not as bad.
pushing power switch they are no change in any voltage

[nomoresonys]

Ok, maybe try it as stand alone, how I do it is unplug cable from powerboard to mainboard on mainboard side leave unplugged for test, use about 1k resistors will need 2 or 3 of them, plug a resistor from 5VSB to PSON, 5VSB to BK and plug in power cord, see if proper steady voltages come up and backlights come on, if not add the third resistor from 5VSB to ADJ and try it.

[nomoresonys]

Use the resistors, they will protect things in case something gets hooked up wrong.

[itronic]

This board don't have 5Vbs. Well it don't produce 5vdc.

[itronic]

I manually put 5vdc to ADJ, BK, PSON. Plug power in and backlights will blink and go back off.

[nomoresonys]

If your saying you don't have standby voltage on the powerboard, then I think you need to fix that first, thinking you should surely have standby or the board won't work correctly, so with the mainboard and backlights unhooked you have no voltage on the 5VSB pin?

[lotas]

If your saying you don't have standby voltage on the powerboard, then I think you need to fix that first, thinking you should surely have standby or the board won't work correctly, so with the mainboard and backlights unhooked you have no voltage on the 5VSB pin?

What can I fix here, if 5vsb is not supplied to the motherboard, it is rather powered from 12v.

[itronic]

Even though its shows it on the label. It doesn't produce the 5vdc voltage

[itronic]

UPDATE. TV IS WORKING FIND NOW.

Tv is power on and working. voltage is steady

VOLTAGE READINGs
THE 4 DIODES READING:
D203 =135DCV
D206= 135DCV
D205=270DCV
D204=270DCV

Big Caps 382v
led 115v on each

CON201

ADJ- 2.27VDC
BK- 3.02VDC
PSON- 3.32VDC
+12V- 12VDC

REPLACED:

R355,R002,C338,EC210,EC201

THANKS FOR THE HELP nomoresonys AND lotas