Toshiba 32av502u

[Zook]

Ello' gents. New to the fourm.

Ive got a Toshiba 32av502u TV that is dead, no power, no blinking led. Boss gave it to me, he was going to through it our but I figured it could be an easy fix.

Cracked her open and the fuse is intact, no power at it though. Im kind of new to large electronic repair (normally I repair cellphones, laptops and the like), I understand the basics but not much beyond that. Would someone care to point me into the right direction?

If I had to take a stab I would assume it is the varistor just right of the power and left of the fuse (top left, from the top view; bottom left from the bottom view)

Might be important info:
>Got almost every tool ill need
>Pretty good with soldering

[Clydeuk]

Re: Toshiba 32av502u

How are you checking for power at the fuse? Set meter for A/C volts, use the blue neutral wire in from the mains input as a ground reference (black lead) and test each end of the fuse. If no power is reaching the fuse I would suspect a failed fuse in the plug or a faulty power switch, in that order, assuming the set has a switch. May not be this model but switch failure was extremely common on some of the Toshiba range.

You can test for A/C between the brown and blue leads on that connector, but you'd need to be very careful not to short them as it's the mains you're dealing with.

[Clydeuk]

Re: Toshiba 32av502u

Sorry can't see the colours too well in the picture, that connector looks more like white and black wires, same applies you should have 110 volts ish (assuming US). I vote a faulty switch.

[budm]

Re: Toshiba 32av502u

Check the DC Voltage RIGHT AT THE TWO LEGS OF THE MAIN BIG BROWN FILTER CAP, it should have about 170VDC.
You may want to read some of these threads also:
https://www.badcaps.net/forum/search...archid=3893421

[Zook]

Re: Toshiba 32av502u

Scratch that, there IS power going to the fuse, IDK what the hell i was testing earlier. Been a long day.

Here is a better picture of the top, with proper lighting.

[Zook]

Re: Toshiba 32av502u

170vdc on the dot.

[budm]

Re: Toshiba 32av502u

Check the voltages as labeled by those two white connectors, and report the readings if you do have 170V on the main cap as in my post 4. More likely you do not have the stby5V right now.

[Zook]

Re: Toshiba 32av502u

No power at either connector.

(assuming you mean what i labeled in attached pic, just wanna double check instead of me assuming)


Edit: Is there a surefire way I can verify its the powerboard? If I can I might just go buy a new one ($30 on ebay)

[budm]

Re: Toshiba 32av502u

The 5V pins should have the voltage there the minute you apply AC to the board, the other voltages are switched on by the main board.
Since there is no 5V Standby to run the board, then there will be no 12V or 24v.
You can try disconnecting the cable between the power supply and the main board to see if the 5V will be present, if not, then the power supply is bad.

[Zook]

Re: Toshiba 32av502u

Okay, still no power to the 5v pins, is the powersupply worth replacing or should I just go for a whole new board?

[tom66]

Re: Toshiba 32av502u

Try checking D203,D204,D505 for shorts.
Try checking for Vcc/Run voltage across C504 (about 10~20V DC)
What is the part # of U501?

[Zook]

Re: Toshiba 32av502u

for testing the diodes im testing for resistance correct?

No Volts across c504

A6251m

[tom66]

Re: Toshiba 32av502u

Use diode mode to test. 0V suggests A6251M is bad. Can't see any fusible resistor inline.

[Zook]

Re: Toshiba 32av502u

My meters diode check is broken (switch to it and it acts like the battery is dying).

[tom66]

Re: Toshiba 32av502u

OK, try 200 ohm or 2000 ohm mode then.

[Zook]

Re: Toshiba 32av502u

D204, D205; infinite
D505; Zero

[tom66]

Re: Toshiba 32av502u

Remove D505 from the board and check it again.