samsung LN-T4661F Negative image & intermittent ghosting

[Oran]

Hi all,

I've got a Samsung LN-T4661F that has what I would describe as a "negative" image. It also intermittently retains images on the screen (ghosting?). i.e. If it sits on the DVD menu for a bit, then you transition to another screen, you can still see the DVD menu. (This isn't consistent.)

All HDMI inputs have the same behavior. I have not tried any other inputs yet.

At the moment I'm thinking that the display/main board is the culprit, but I haven't ruled out the TCON board. Power is good, & it's not behaving like other tab bond issues I've had in the past.

I have not disassembled it yet, but I'm going to later today. In the mean time, here is an image of the screen.

Any ideas?

Thanks in advance!
- Oran

[freakaftr8]

Re: samsung LN-T4661F Negative image & intermittent ghosting

I think I would start by looking at the T CON board especially the AS15 gamma ic. it looks like it went belly up. To be sure we can do some voltage tests with a voltmeter and you'll see the voltage readings off of that processor the points on the board where you're supposed to test these Voltages should iincrementally go up or down from 0 to about 12 volts if you have any points in the middle that are dead or in off reading between 0 and 12 volts or from 12 volts to 0v that AS15 is dead and I will exhibit your problem

however the inverted colors in thefluorescent highlighting looks to be a setting issue on the main board for LVDS bitrate and odd/even parity for the panel. so this just crept up on its own you didn't replace the t-con board at any time or the main board at any time?

[Oran]

Re: samsung LN-T4661F Negative image & intermittent ghosting

Thanks! I'll disassemble it shortly and get to the TCON board.
In researching the issue, I did see some info related to that chip, but it was for a different model. If it pertains to this model as well I'll make sure to do some more research.

I am working on this for a customer, so sadly I can't guarantee the TCON board has not been replaced previously. In addition, it is now on its 2nd or 3rd owner. The story is that it just occurred.

[freakaftr8]

Re: samsung LN-T4661F Negative image & intermittent ghosting

Does that model have a USB? You could try starting with a firmware update if there is any available. sometimes settings get messed up in the EEPROM unknown reasons

[Oran]

Re: samsung LN-T4661F Negative image & intermittent ghosting

Does that model have a USB? You could try starting with a firmware update if there is any available. sometimes settings get messed up in the EEPROM unknown reasons

Thanks for the tip! It has a Wiselink USB port that can apparently be used for updating firmware. That led me down an interesting path. While hunting for the firmware, which I have not yet been able to find, I've found some threads indicating severe (though correctable) image issues arising from firmware updates. Now I'm wondering if someone has attempted a firmware update which resulted in these issues and just decided to offload it on someone else. Before I disassemble it I think I'm going to get the customer to bring the remote (they never bring the remote! arggh) so I can get into the service menu, verify FW ver and check settings.

[freakaftr8]

Re: samsung LN-T4661F Negative image & intermittent ghosting

Cool keep us posted

[Oran]

Re: samsung LN-T4661F Negative image & intermittent ghosting

Welp, the customer finally brought the remote. Despite doing a reset and verifying all the settings I could, no luck. I'd try flashing it, but I have not been able to find any firmware files for this model. Tomorrow I'm going to disassemble the unit and try to test voltage on the TCON. I think I'll need to do some more research on that, as I'm not as familiar with that board as I am with others. It sounds like the aforementioned chip is a common point of failure, so I suspect there is some info I can find. Thanks for your help!

[Oran]

Re: samsung LN-T4661F Negative image & intermittent ghosting

Hi there, just wanted to post an update. I ended up just taking a chance & replacing the TCON board and it solved the problem. Thanks for your help!

[budm]

Re: samsung LN-T4661F Negative image & intermittent ghosting

Thanks for the follow-up.
So dose the T-CON board have AS15 or AS19 IC?