Hitachi 58HK6100U black (blue tinge) screen

[mace]

Hi,

I have picked up a Hitachi 58HK6100U smart TV with a black/blue screen issue.

It's a vestel unit, using the MB230.

Visual inspection shows no obvious issues with caps, and diodes on PSU all look reasonable. I've not been able to check voltages, as I haven't spotted a schematic that matches the power supply, a 17ips72.

I've confirmed that the set boots successfully, albeit without picture. If I disconnect either the left or right ribbon cables, I get picture on the other side.

I noted a few bad lines at the bottom on the right hand side of the screen, picture attached. This may have occurred during collection, so might not be related to the original fault.

Can anyone point me in the right direction as to where to look next?

Thanks.

[dskall]

Re: Hitachi 58HK6100U black (blue tinge) screen

I would check t-con voltages.
And a video with a similar problem. Tv works with either side unplugged but doesn't work with both plugged in.
https://www.youtube.com/watch?v=77ty...chaelDranfield

[mace]

Re: Hitachi 58HK6100U black (blue tinge) screen

Thanks dskall, I'll rewatch that video. Do you know of any schematics for these boards/test points I can check the voltages?

[cheeky2]

Re: Hitachi 58HK6100U black (blue tinge) screen

Thanks dskall, I'll rewatch that video. Do you know of any schematics for these boards/test points I can check the voltages?

Your issue with your TV will be one of three things in order I suspect the issue is with your TV. The screen, the main board or the tcon.

[mace]

Re: Hitachi 58HK6100U black (blue tinge) screen

I suspect the issue is with your TV.

Very good 🙂

[dskall]

Re: Hitachi 58HK6100U black (blue tinge) screen

Need good pictures of t-con.

[mace]

Re: Hitachi 58HK6100U black (blue tinge) screen

Photo of tcon as requested. Let me know if you need any close ups?

[dskall]

Re: Hitachi 58HK6100U black (blue tinge) screen

You have vgh, vgl, vcom, vcc test points

[mace]

Re: Hitachi 58HK6100U black (blue tinge) screen

Thanks dskall,

Following measurements are with both halves of the screen connected to the t-con:

vin1: 12.1v
vin_12v1: 12.1v
vcc3v3: 3.28v
vcc1v8: 1.7v
vcc1.2v: 1.18v

vcom_l/r: started higher, slowly dropping, measured at 380mV after about 5 seconds.
vgl: 157mV
vgr: 18mV

Repeated measurements with either left or right hand ribbons disconnected:

vcom_l/r: 7.14v
vgl: -6.08v
vgr: 24.7v

[nomoresonys]

Re: Hitachi 58HK6100U black (blue tinge) screen

this does look like similar issue as in the video, test all the caps on the panel driver board, one probe on ground other on each side of cap, one side should continuously beep, other side should not have steady beep.

[nomoresonys]

Re: Hitachi 58HK6100U black (blue tinge) screen

you might get lucky and find one that is hotter than the rest, which would probably be the culprit.

[mace]

Re: Hitachi 58HK6100U black (blue tinge) screen

The only short to ground I've spotted so far was across B402, is that a bridging link?

[nomoresonys]

Re: Hitachi 58HK6100U black (blue tinge) screen

probably is, it's not a cap.

[mace]

Re: Hitachi 58HK6100U black (blue tinge) screen

you might get lucky and find one that is hotter than the rest, which would probably be the culprit.

Yeah, wish I had an IR camera, that would be a good check, assuming that it's shorted enough to heat up visibly.

[mace]

Re: Hitachi 58HK6100U black (blue tinge) screen

probably is, it's not a cap.

Took it off, and lost ground to quite a lot of the bypass caps, so looks like B is bridging link on these boards (for anyone that comes across this thread in the future).

[dskall]

Re: Hitachi 58HK6100U black (blue tinge) screen

Try checking those test points to ground, with and without ribbons connected and see if you can find a short. I don't think you have a bad dc to dc converter if you are getting voltage when first turned on.

[TonyDoo]

Re: Hitachi 58HK6100U black (blue tinge) screen

Hitachi 58K6100U. I have had 3 of these in for repair recently with this fault. On all 3 if I unhook the right-hand side (from back view) screen driver board the TV shown a pick on the other side of the screen. When I had an hour or so to spare I checked all the caps and anything else easily checkable on that board. Everything checked OK. There is an eight-pin IC on the board marked
BL25080A which looks easy enough to replace, so thought worth a go to see what happens, but I cannot find one anywhere.

[TonyDoo]

Re: Hitachi 58HK6100U black (blue tinge) screen

Before anyone pipes up, I did try the T-Con board first

[nomoresonys]

Re: Hitachi 58HK6100U black (blue tinge) screen

well not much is coming back on those numbers, its saying its an eeprom, maybe heat it up with a hairdryer for a couple minutes then try the tv, try it right away, don't wait til it cools back down.

[Tushea2023]

Re: Hitachi 58HK6100U black (blue tinge) screen

Sorry to hijack an old thread but can't find anything else on the net and have the exact same issue as above. Can I ask what was the issue in the end? TIA