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Sony Alpha a6400 / ILCE-6400.

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Screen replaced but still not working.

Everything in the camera works perfectly except the screen. The sensor which detects when the screen is open also works.

To try and resolve the issue. I have replaced the touch screen and the display driver PCB but the screen still isn't working.

I have reseated and checked the hinge flex cable and can't see any obvious signs of damage.

Even though there doesnt seem to be any visible damage to the flex cable could it still be the problem?

Your thoughts and ideas are most welcome.

Update (07/28/25)

After checking the ribbon cable with the Digital Multimeter and ordering a new one. The issue has been resolved. Everything is now working well.

I just need a new gasket for around the screen if anyone knows how that's done?

Thank you so much for all your help and special shout out to @jayeff, he has been been amazing 👏👏👏

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tem umas fitas pra isso ( como uma fita dupla face)

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Hi @samuelluca19941

With the camera turned on etc, try shining a flashlight at an angle close to the screen and check if you can see any images on the screen at all.

They will be very faint if they are there, so trying this in a darkened room may help.

If you can see images, then there's a backlight problem with the screen.

This could be due to a faulty backlight power circuit or a faulty screen backlight flex cable/cable connection

Check if there's approx. 3V DC between pins1-3 & 4-6 on CN0002 on the LC-1045 flex board that the screen's small backlight flex cable connects to.

If there's no voltage there then it is supplied by a DC-DC converter (IC 5300) on the SY-1094 mainboard - check CN3000 pins 49 & 50

If there is voltage, check if the flex cable is physically OK as best as you can tell

If you can't see any images it could be a faulty mainboard in the section dealing with the screen. Here's the service manual if you wish to delve further into the circuit.

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Hi @jayeff thank you for the detailed an excellent response.

I replaced the LCD Screen and the LC-1045 display driver board already.

I've checked the flex cable, there does not seem to be any physical signs of damage.

I guess there are 4 options.

1: The new LED I punched is faulty

2: The new LC-1045 board is faulty or both of the above

3: The flex cable is damaged but it's not visible

4: IC 5300 on the main board is broken.

Q1: If it is the IC 5300 thats the problem would i need to purchase a new SY-1094 mainboard?

Q2: I've never checked such small electric components for voltage before. Is there a special multimeter I need? If so can you recommend one and any example video?

I'm quite technical and understand where all the components are that need checking so I just need to make sure I'm using the right equipment.

One again thank you so much for your help.

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miltimetro simples serve bem, so as ponteiras precisa ser mais finas, voce pode soldar alfinetes ou agulhas de costura na ponta das ponteiras...

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@samuelluca19941

Just wondering, did you try cleaning the eye sensor?

The eye sensor detects if you're looking through the viewfinder and switches the screen off. Not sure how it works but if it works on amount of light then when your eye is near/on the viewfinder I assume it would be darker there then if it weren't, so being greasy (due to skin touching it) etc would be the same i.e. it thinks it's darker than it should be.

An ordinary DMM (digital multimetr) is sufficient but when testing small components the meter's test lead probe tips may be too fat. I have a pair of adapters (example only to show what they look like) that I slip onto the probes and then clip a pin into making for a narrower tip. A steady hand is also useful ;-)

I would try to isolate the problem a bit more first i.e. board problem or screen problem

If it is only the backlighting, have you still got the original screen?

Don't know what type of backlighting is used (presumably LED but maybe still fluorescent??) so if you have, disconnect the backlight cable from the board and then use a DMM's (digital multimeter) Ohmmeter function to measure between pins 1 & 4 on the screen backlight cable to see if there's a resistance reading at all.

Do this for both for both screens.

If they measure the same then most likely the problem is on a board. If not then it's either the original screen is OK and it's a board problem or the replacement screen is faulty and the board is OK, not conclusive but.....

If it is the board check for backlight voltage as in the answer above. If there's no voltage on CN3000 50 then check IC5300 pin6 and pin 5 each one to earth.

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Hi @jayeff,

The eye sensor works well as the viewfinder turns off when it is a little away from my face.

I'll check both screens as you said.

If it is a onboard problem would I need a whole new mainboard? They are quite expensive even to import.

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@samuelluca19941

On the SY-1094 board there's a dedicated fuse F0004 on the UNREG_BL lead - see p.109 of 165 lower right side of page next to D (power 4/4) (page 2-6) which is used for the backlight power supply that is fed to the IC5300.

Maybe also check if that is OK. Hopefully it's designated on the board.

If it isn't there a boardview diagram on p.157 showing its location on the A side of the board, lower right side, 45° up and to the left from IC5300

Did you see images at all when using the flashlight?

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Hi @Jayeff ,

Yes, I still have the original screen so that can be tested.

I'll buy a cheap DMM from Amazon and fasten some metal needles to it if needed.

Does this seem okay to you? ... https://amzn.eu/d/bfRi9R4

I can then test ...

> both screens,

> the flex hinge cable,

> the F0004 fuse

> the IC5300 on the mainboard

Basically follow the chain of power to see where the fault originates.

This should then give me a good idea of what needs to be done instead of buying every part when they are not need.

O and yee, I did check the screen in a dark room with a flashlight but not a flicker.

Fingers crossed we can find the issue without breaking anything. If nothing else this is very interesting to work through.

Thank you once again for your help. I do really appreciate it.

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@samuelluca19941

The DMM you showed is OK to use.

It might be a power problem as I've just noticed that the same voltage that supplies IC5300 for the backlights also is used to supply the screen voltage - VDD on CN0004 pin 48 of the LC-1045 board going to the screen.

There's also a 1.8V VDDIO on pin 33 which is multipled from the EVF but since the EVF is working OK it should be there, so it might be back with IC5300 or the fuse hopefully ;-)

What's the history of the camera - dropped, wet, don't know etc?

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Hi @jayeff , from what I understand it got knocked while filming at a tennis event. There is no physical signs of damage just that the screen stopped working.

The viewfinder and the sensor that detects if the screen is open or closed work find.

What is interesting is that the sensor on the same flex cable/hinge cable as the screen which detects if it's open or not works but the screen itself doesn't. That's assuming it's what the sensor does and there isn't another one somewhere else.

But yes, it got a knock but no other type of damage that I'm aware of.

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Samuel Lucas crwdns2934231:0crwdne2934231:0
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