Sony KDL40SL140 TV no 3.3V standby power?

[bill free]

Fuse at power supply input is OK. AC is present at first stages of ps
circuit but can't find any DC. I have the schematic but there are no test
point voltages shown on schematic except at standby output connector. No
voltage present at any pins at the ps output connector. I presume the ps
is the problem but wanted to ask here if it could be anything else before
buying another power supply.

 

[Mark Zacharias]

Fuse at power supply input is OK. AC is present at first stages of ps
circuit but can't find any DC. I have the schematic but there are no test
point voltages shown on schematic except at standby output connector. No
voltage present at any pins at the ps output connector. I presume the ps
is the problem but wanted to ask here if it could be anything else before
buying another power supply.

I would say just makes sure it's not being loaded down. See if it comes up
with no load.

By the way, sometimes you can get the boards cheaper from second sources,
like ShopJimmy or Tri-State Module.

Mark Z

 

[bill free]

Mark,
Thanks for the good advice, you were correct, something is pulling down the
standby power. I unplugged the connector for the wiring leading from the
ps board to the tuner board and with the connector off there is 3.3 V
standby power on the ps board pins. So maybe the problem is on the tuner
board and not the ps.

I think this may have been caused by a nearby lightning strike about two
days ago. There is no visible damage to the tuner but it probably got
tested in that storm. I usually unplug the antenna when there is lightning
but neglected to do it this time.

 

[bill free]

By the way, sometimes you can get the boards cheaper from second
sources, like ShopJimmy or Tri-State Module.

Mark Z

Thanks for the source suggestions. Seem to be plenty of power
supplies around for this model TV for $50 up but the BM5 tuner (main)
board is much more expensive, plus there are few (if any) available.

The BM5 board must be first to die from lightning strikes.

Looks like there may be people who repair these boards for around $200
but this model TV is only worth $200 in good condition.

Probably not worth pursuing further.

 

[N_Cook]

Mark,
Thanks for the good advice, you were correct, something is pulling down the
standby power. I unplugged the connector for the wiring leading from the
ps board to the tuner board and with the connector off there is 3.3 V
standby power on the ps board pins. So maybe the problem is on the tuner
board and not the ps.

I think this may have been caused by a nearby lightning strike about two
days ago. There is no visible damage to the tuner but it probably got
tested in that storm. I usually unplug the antenna when there is lightning
but neglected to do it this time.

I hope you have 3 foot long insulated tongs for that antena isolation
operation.