Sony fw-55bz35f professional display

[EazyBone]

This Pro TV has no power. No light indicator or nothing.

I checked standby and all other voltages, it has zero volts on every point of connector.

Fuse is fine

Main cap gets 160v steady

I can't find any voltage on the cold side, the hot side does have some things.

Is it possible something has gone bad but didn't blow the fuse? Any direction would help. I'm pretty damn sure I should at least get standby... But these sonys mess with my mind.

[nomoresonys]

Start with basics, I check the diodes, resistors and transistors on top of board first, then check the bottom and check for bad solder joints, if nothing found can go from there.

[EazyBone]

Yes, I'm feeling the need for some reassurance lol, I don't get any voltage coming off the octocouplers, I guess I'm looking for reassurance that it's not mysteriously the main board not turning on the stupid power board because sonys just suck imo lol

But all resistors seem fine, too late to check solder joints but will be a tomorrow thing.

I get your name now, damn sonys

[R_J]

The first voltage you need is standby voltage, check fuse resistor R915, ic901 is the standby pwm. If the resistor is open ic901 is likely bad.

You need 3.3vdc across C950a (or check for 3.3vdc on FB950 (near cn6401)

[nomoresonys]

Yes, I'm feeling the need for some reassurance lol, I don't get any voltage coming off the octocouplers, I guess I'm looking for reassurance that it's not mysteriously the main board not turning on the stupid power board because sonys just suck imo lol

But all resistors seem fine, too late to check solder joints but will be a tomorrow thing.

I get your name now, damn sonys

My xbr65x900c was a nightmare, spent WAY too much time messing with it, was just trying to figure out the issue. Funny thing is, this 900c is edge-lit so the picture is always going to be substandard compared to full array, it's not worth shit imo.

[EazyBone]

The first voltage you need is standby voltage, check fuse resistor R915, ic901 is the standby pwm. If the resistor is open ic901 is likely bad.

You need 3.3vdc across C950a (or check for 3.3vdc on FB950 (near cn6401)

So I already ordered replacement PSU because obviously it's the PSU, and yes the original was dead

R915 is fine, is there a way to test ic901 in any way?

Always curious to try and fix a psu

[R_J]

Check the voltage on the ic's drain pin (lpin 5) looks like pin 8 is hot ground. If you have that (160vdc) voltage, check the ic's vcc voltage, using hot ground for meter negative, check the voltage on pin7 or D902 cathode (white line) and D902B, these voltages should be around 20vdc depending on the state of the ic.
If you have around 9vdc or the voltage is changing between 9~15v on either of the two diodes it may be that C904b or C907 is bad, don't check them just replace them.

[EazyBone]

Great thanks, will check this out within the week or so and post results. Got a backlog of tvs to handle :/

Thanks!

[droxide87]

Hello, I know it's a little off-topic, but I'm trying to source the firmware for this exact model, but it seems sony has discontinued support and google is a big let-down, any chance someone can direct me to a source? would be greatly appreciated!