my attempt to fix

[orangetech]

Hello everyone. Im new on here. I have a plasma tv that is not powering on. The model is a maxent mx-42vm10

I looked already at the fuses. I found a bad pico fuse on one of the boards that does the inverting. its better now.

Power is making it to the main switch on the back but not the standby button on the side. I have never been under the hood on a plasma tv before and am a little over overwhelmed by how much there is going on in here. Also I have no schematic(like always I cant find one).

It seems that I am getting a lot of ac(60+vac) post rectifier. Is that normal?
The rectifier is reading like a half wave. Is that normal?
Im getting 120vac on both input leads to the relay.Is that normal?

Thanks in advance for your help!

[mariushm]

Re: my attempt to fix

Pictures of the boards please.

I would say seeing AC post rectifier is not normal. Test the bridge rectifier or the four diodes. Shouldn't be half wave.

120v to the relay would be normal depending on how the tv is made.

There's usually a small standby section on the power supply which does standby and powers some logic that - when tv is powered on - enables the relay to give 60v and ~160-190v to the boards handling the plasma panel.

[tom66]

Re: my attempt to fix

Those seem normal. What is the fault with the TV? Pictures of the chassis?

[budm]

Re: my attempt to fix

"It seems that I am getting a lot of ac(60+vac) post rectifier. Is that normal?" That is because you are using chassis ground as the ground ref for the PRIMARY (HOT side), The Primary circuits ground ref point is the negative leg of the large filter cap that is fed by the bridge rectifier. The Secondary side circuit ground is the Chassis which is also tied to the safety ground if the TV uses 3-prong plug.

[orangetech]

Re: my attempt to fix

here are some pics