Sharp LC-42D64U... no video inputs work, OTA works

[budwich]

Re: Sharp LC-42D64U... no video inputs work, OTA works

it is certainly worth an attempt. i have started to go thru the troubleshooting section of the SM... starting at "no composite video" on input 1,2,3. It gives some check points to look at so I will try to do some "checking" with my scope to see I can figure out anything. Hopefully I won't blow up the thing.

[Davi.p]

Re: Sharp LC-42D64U... no video inputs work, OTA works

Maybe i'm inattentive, but i don't think that has a sense to follow the flow chart for no video, since you have near all inputs not working, since hdmi and composite follows a different path to the IC8001 CPU through different ICs, so unless those ICs have the same power supply at fault (watch for linear regulator on the main board) then the issue is software.

[budwich]

Re: Sharp LC-42D64U... no video inputs work, OTA works

Hey Davi.p...
we tried your suggestion with the hard reset from the 2 page of service menu (called industry init).... The "init" started for about 4-5 seconds... then the screen went red background and an error appeared with "industry init error ( 11)". At this point, the set was locked up with no response from the remote or panel buttons. Unplugging power took it back to "normal" set operation. Didn't find any thing on this error yet.

Then we decided to do the "eep recovery" on page 32 of the service menu. Similar results... the item line shows some "progress marks" (ie. starting to do something) but then an "ERROR" word shows up. This time though we can power panel off with the side buttons. The panel starts up normally. So overall we were not able to cause a good reset of the panel either "hard" or thru "eep recovery"... :-(

BUT through all this, all the analog video inputs work (ie. rca vid and svid) along with the ota tuner. This better than when we started so something happened. Still no hdmi, component and vga.

It is looking more like a firmware / prom issue and probably needs the main board to be replaced.

Not sure if the "error 11" means anything to anyone or points to something specific.

[Davi.p]

Re: Sharp LC-42D64U... no video inputs work, OTA works

I hope i'm wrong but it seems this Sharp it is made in a very strange not convenient way, in all the other tv i know the firmware contains a copy of the standard settings for the eeprom so when config becomes corrupted a service reset will restore factory situation, but maybe i've heard this time ago, this is made so, the eeprom have a backup of settings in a certain area that are copied to the active area when you do a reset, unfortunately it seems corrupted so also the upgrade is no more possible so i need to find answers on the smnual or an eeprom dump.

[Davi.p]

Re: Sharp LC-42D64U... no video inputs work, OTA works

No dump around... you can read it by another mainboard.

[budwich]

Re: Sharp LC-42D64U... no video inputs work, OTA works

:-( It looks like we are stuck with tracking down a replacement main board.

One other thing that is of note. The "plug detection" circuitry has some issue. On the first 3 ports (input 1,2,3), plug detection works as it should. The port is "not available" for input selection with nothing plugged into it. IF you plug into it, the port then gets "marked" and is available for selection. Port 1, 2, and 3 are analog / rca ports and are on the main sub input board that is across the bottom / bakc of the panel.

On inputs 4-7, they have the "port available" mark always set, even though no plug inserted. Inputs 4-6 are hdmi and port 7 is vga. So there appears to be some issue with "hot plug detection" / "plug detection" circuitry on those. I haven't yet gone thru the SM to look at the flow to see what's up there but perhaps some form of "short" has made its way to the detection circuit such the pin 19 (I think for hdmi) is being detected across all the ports. Can't remember for vga, but some ground on one of the 15 pins also causes the same detection.

In terms of board layout, hdmi 4 is on the side sub board while hdmi 5,6 and vga are on the main board.

[Davi.p]

Re: Sharp LC-42D64U... no video inputs work, OTA works

This can be normal 'cause on Samsung tv ususally it is so...

[budwich]

Re: Sharp LC-42D64U... no video inputs work, OTA works

not sure (about hot plug / plug "sense"). On my other samsung set, it only shows / highlights inputs that have plugs in them and greys out others that are empty. most hdmi inputs that I have seen are normally "sensed" for cables using pin 19.

I am thinking there is an issue with the silicon graphics chip sii9185 which receive both hdmi signals and the vga signals based on the trouble flow charts and the board schematics, although the "plug check" for the vga thru some form of the eeprom for the DDC data (resolution capability checks).


OOPS... I screwed up... the sii9185 appears to only handle the hdmi. So vga goes else where.

further. The component (rgb / vga) go thru a TB1305FG. This "thing" needs some setup to provide the appropriate input and output signal manipulation. It would appear that indeed, the issues with the eep and subtending work area has a problem such the appropriate values are not being set in the subtending IC.

certainly well beyond my current knowledge level... :-)

[Davi.p]

Re: Sharp LC-42D64U... no video inputs work, OTA works

The Samsung LCD i owned (more than 10) all shows some inputs without signal, it shows black screen and a box with the input name..

[budwich]

Re: Sharp LC-42D64U... no video inputs work, OTA works

We decided to "throw in the towel" and buy a used main board off ebay. Fingers are crossed that it will resolve the issue as the panel's picture / display is very good.

[budwich]

Re: Sharp LC-42D64U... no video inputs work, OTA works

Used main board installed today. Factory reset and everything is working so it would appear that possibly an eeprom corruption or otherwise. Anyways, friend is happy, me too.