Hitachi 48C6 lcd artifacts then warm grey

[Ciberdave]

I don’t see any visible bulging or bad caps on the PS board but there’s a High pitch variable whine noise coming from the transformer on startup.
I’ve replaced caps before on pc and lcd TVs but never delved into troubleshooting much more than checking for visible signs of bad caps.
I read Bud's pdf on general troubleshooting but, has anyone had this audible whine coming from what sounds like the transformer?

Sometimes the TV will show the sources select screen with various artifacts and wide hashed lines on the screen in the background it seems. After the bootup "please wait" message sometimes it shows the sources select but sometimes I just get a warm grey screen.
Do these pictures and symptoms sound like a bad Tcon board?

[nomoresonys]

Re: Hitachi 48C6 lcd artifacts then warm grey

Flip it over and closely inspect all your solder joints.

[Ciberdave]

Re: Hitachi 48C6 lcd artifacts then warm grey

Flip it over and closely inspect all your solder joints.

One transformer leg appeared to have a cold solder going to a diode. Noise still exists after touching up the solder pad.
It almost sounds like if a very small bit of insulation on the transformer winding has a hole in it and what I hear is a very small arc.
Do faulty diodes make this sound?

I could easily find and order a new/used board on eBay but this is enjoyable troubleshooting and learning.

[nomoresonys]

Re: Hitachi 48C6 lcd artifacts then warm grey

If your not sure about that diode, you could lift a leg and check it out of circuit, diode mode on multimeter.

[Ciberdave]

Re: Hitachi 48C6 lcd artifacts then warm grey

Diodes check out good. I cant find an exact match replacement board on ebay. I see many other boards of the model KB-5150. Is it possible to use a different board, one of the other KB-5150's of a similar size. I'm assuming I would need to adapt the connectors, is this something I should try.

[nomoresonys]

Re: Hitachi 48C6 lcd artifacts then warm grey

I'm not positive but this looks to be a match, I didn't see the white sticker that is on yours to try to match up the numbers on that one, don't know why, maybe it's on the back of the board?? or fell off? not sure: https://www.ebay.com/itm/hitachi-49c...oAAOSwxtVcEEc0

[Ciberdave]

Re: Hitachi 48C6 lcd artifacts then warm grey

That looks like the exact match after closely looking at the connectors. just for curiosity's sake, what do you think could go wrong if I use another board that looks similar but came out of a different model altogether?
https://www.ebay.com/itm/TV-PROSCAN-...A/164460133424
It appears only the 120v connector is different.

[nomoresonys]

Re: Hitachi 48C6 lcd artifacts then warm grey

That's a very good question, I know that powerboards don't seem to be as fussy as mainboards when it comes to compatibility, but you probably should see what the gurus have to say, I'm just not sure.

[Ciberdave]

Re: Hitachi 48C6 lcd artifacts then warm grey

Just installed a new power supply board of the exact replacement model. No sounds coming from the unit. It worked good for about 2 mins but then started to get artifacts and wide vertical bands on screen. Then it fades to warm grey? Any ideas?
I found a main board that's cheap enough but I'm not sure where to troubleshoot to rule out tcon vs main board?

[nomoresonys]

Re: Hitachi 48C6 lcd artifacts then warm grey

Not sure but that what you just described does indeed sound like a possible faulty tcon.