Screen Black But Responds to Touch, No Backlight, No Video

BACKGROUND : I have been in the process of replacing the USB C port bc it was mangled, only to find that now I’m having this issue. I have reseated the connector ribbon cables over 4 times at this point (literally all of them and specifically the LCD one) to no avail.

After I got the USB C port on, I put it all back together tested it, and it worked fine expect charging the opposite way. So we heated the connector back up to reflow the bottom sets of pins.

Next I began putting it together again to test, turned it on, realized nothing was working, checked all the cables and realized the LCD ribbon cable wasn’t seated all the way in. I reseated it, tried it again, and it’s been doing this.

CONCLUSION: Any idea what’s wrong? Did having the LCD ribbon cable seated improperly for a split second fry the screen? I’m assuming at this point the screen is dead. What do you think?
Model HAC- 001

hola …
hay dos diodo cerca del conector del puerto de lcd reemplazar los dos componetes y hacer medición antes de encender si los datos están correcto en medición de diodo las líneas debe estar en 0.440 a 0.700 …verificar antes de instalar bat…

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Cual es el nombre del diodo?!? Donde?

Have you checked inside the LCD connector for bent pins? as it’s pretty common beginners snag the ribbon on a pin or more and bend them by forcing the ribbon in, based on what you’ve described it sounds like this might be the case. I’d use your phone and zoom in good lighting and have a look if you haven’t got a microscope :+1:

The diodes the other poster is referring too are by the 8316 IC nearby and they relate to a couple of rails for the LCD, though if either of these had failed (particularly the one on the negative rail) I’d imagine it taking the 8316 IC out too, so don’t worry about this for the time being :slight_smile:

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debajo del ic 8316 estan unas resistencia verificar componente las resistencia que va al capacitor tiene que tener salida y entrada de lectura verificar

thank you! So as far as we can tell, the LCD connector pins arent bent. My friend has a really good ocular microscope something like a 350x zoom that we have been using. He doesnt see any bent pins in the connectors but we will always check again. the scope has been extremely handy for things like this because its such a good microscope.

I’ll definitely check those diodes and IC though. Are parts even available for replacing those?

:+1: If your getting your +5 and -5V following prompting the console to boot at the two VOUT locations I’ve marked in this image then your diodes and IC are all good. If no then more likely the diodes / IC at fault

If you get your rails but still no display on :LCD, and connectors been ruled out then I guess you’d start looking into backlight related issues or LCD display issue in and of itself

In regards to getting the parts, you can get the IC’s new on mouser afair preballed, the diodes I usually pull from donors, there is a part number for the diodes used in the application circuit of the IC datasheet but I’ve heard some people saying they’ve had no luck with them.

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so this was actually what we tried to go off of the other night and we noticed it looked significantly different from our model. The diodes and caps were in different places and the row of diodes at the bottom were also not a row. Any idea what model that image came from ? this switch is an HAC 001

Also i cannot for the life of me figure out how to add pictures, keeps saying “error, cannot embed media in a post”

Yeah they shifted things around a bit on other board revisions but the circuit connections are the same between the two, just look at those two big ceramic caps as your reference point and how the traces are connected to them and you’ll be good :slight_smile:

tbh I can’t even rememer I took this image years ago :open_mouth:

Also, I’ll just add, any of those resistors in that gang there, if any of them aren’t propely soldered / knocked off / failed open, this can also cause those rails to not be present too. just thought that was worth mentioning.

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you’re the best dude <3 I will be working on it tonight with the friend so we will check on those again since now we know they are the same, just shifted around. if you think of anything else, let me know. Ill keep yall posted

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Do you happen to know where to find the values for the diodes ? Im guessing in the datasheet for the 8316 IC ? I think we will just order the parts and replace all of that at the most. Especially if the LCD is getting 15V (or is it 17V?) like it should, indicating that the LCD itself is still good. If anything, we will probably end up measuring the diodes to check values

You got it :+1:

I’m guessing your thinking of backlight voltage here? either way, no, just because a rail is present doesn’t confirm or deny if the LCD is good/bad I’m afraid, it just tells you that whatever is creating said voltage on the mainboard is doing it’s job, I mean, there are exceptions, for example, if the LCD failed internally and a line which coresponds with a rail input was shorted to ground thus pulling the rail low, in which case that could do it (but it’d be very rare). There are many rails going off to the LCD conector > LCD, 3.3V (iirc) 1.8V, the +5 and -5V (we talked about those last two). afair 15/17V doesn’t make it’s way to the LCD connector (someone correct me if I’m wrong) , think your thinking of the BL (4-pin ribbon)

In your case, if the +5V rail is present and the -5V rail is present following a prompt to boot (at those points in my image) then it’s telling you the diodes and the 8316 IC (and support circuitry) are all good, if you don’t see anything on screen and you’ve already ruled out the LCD connector itself (which has those other rails going to it which we talked about) then the only thing left that could be the problem is a backlight related issue or and LCD related issue.

Hope that all made sense.

General rule of thumb, if it ain’t broke, don’t fix it. Verify there is even a fault prior to even contemplating removing ir replacing compenents :slight_smile: plenty of guys and gals have done the opposite and made the problem/s worse knowingly or unbeknownst to them, and then the chasing of the tail begins :wink:

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thank you thank you, I really appreciate it. Sounds like I wont get around to diagnosing it more tonight, So if any updates, they would come tomorrow or later. If i find a fix, I will make sure to update the forum.

Do you happen to have the mouser link for the backlight IC? I see people calling it the 8316 IC but then I also see people referring to it as the TPS61163A. so I’m definitely confused on what IC/part of is or what I’d order from mouser.

Hi, I’m French so don’t be too hard on me.
To begin with the 8316 is not responsible for the backlight. It may be the cause of a black screen, but with a backlight present. Maybe I didn’t understand correctly, but your console starts or not. Furthermore, I saw that you had a problem with a poorly connected cable. It doesn’t matter, you reconnect it, but before restarting the console it is better to disconnect then reconnect the battery to be sure that it is taken into account.