Raspberry Pi Forums

First, I should clarify that it was fine yesterday, and while I did not start it up connected to the same screen as it was previously, I have since, and have been unable to get it to work on either of my HDMI computer screen.

Details:
- If plugged-in with HDMI (regardless of power-supply), the red LED stays on, the green blinks once, and then nothing happens
- If plugged in without HDMI, it boots without issue
- When I measured the voltage used when the HDMI cable was attached, it never went above 1A in current draw. Once I removed the HDMI it immediately started rising, until it sat at around 0.6A. It would drop to 0.4A if the HDMI cable was plugged back in.
- This is not resolved by: Changing Screen, Changing Charger (Max known PSU rating was 2.1A), Changing HDMI cable, reflashing SD card, changing SD card or changing charging cable.

Chargers/PSU's used:
- Computer 5V dedicated charging port
- Powerboard 5V 2.1A direct USB out
- Samsung S9 Charger (5V, 1.0-2.1A)
- Nintendo Switch USB out
- TP-Link Bluetooth hub PSU (5V, 1.0A)
- Samsung Wireless Charger Supply (5V, 400mA)

Cables (USB) used:
- Wacom USB tablet
- Switch USB controller cable
- Generic MicroUSB cable x4

Cables (HDMI) used:
- Unknown White HDMI cable, seems solidly built
- Cheap, thin HDMI cable
- High-quality, but long (2M) HDMI cable

Displays used:
- 2X AOC Computer Monitors
- 1X Sony LCD TV

Configuration that previously worked without issue:
- AOC Computer Monitor
- Wacom USB cable
- Powerboard USB out
- Thin, dodgy black HDMI cable

I'm flat out of ideas, and would greatly appreciate any help
NOTE: It has booted before on my available PSU's without issue, with HDMI plugged in. This is a recent development

This is not resolved by: ... Changing Charger (Max known PSU rating was 2.1A)

It's probably an issue of insufficient voltage when you try to start with HDMI plugged in, not current.

"Chargers" are not ideal as power supplies for the Pi 3B+ because they often allow the voltage to drop when a higher current is drawn.
To make matters worse, flimsy USB cables also cause the voltage to drop.

You could try an expensive cable such as Anker Powerline+ or for about the same price get thee official Raspberry Pi 2.5A power supply.

I understand this, but the confusing part is that the day before, using the exact same power supply (5V, 2.1A) it booted without issue, while plugged in. I've already looked into this line of reasoning, and have had little success.This was with every cable the exact same, same screen, entire setup the same as the day before, and it still refused to boot.

Some questions:
1) When the boot was successful how did you shutdown the pi? (Hopefully not just by "pulling the plug")
2) What are you using to "re-flash" the uSDHC card?
3) If you can boot w/o HDMI connected can you login via SSH over the network (assuming you can activate it etc. by writing the necessary files to the uSDHC card first)? If so, what does tvservice -s report?
Trev.

1. Yes, I did. Admittedly it's not best practice, but I can't see it causing anything outside of corruption of the SD card. It is also my only option for restarting if it has not actually booted
2. I'm using DD on Linux, with the following syntax 3. Running tvservice on a fresh install of Raspbian gives me

In addition, the display is picked up, with returning the correct information, and the EDID dump seeming sane, but no picture comes out regardless of what I do.

The likely suspect is that none of your "psu/charger" pass the recommended minimum power supply specifications for the RPi3B+.

Except it booted without issue two days ago, with the same charger. It has already run without issue with HDMI plugged in, but it now refuses to boot. Certainly, it's unlikely any of mine are specced correctly, but my Raspberry Pi has booted on considerably less before it stopped doing so. The Raspberry Pi has booted to a display since I got it, it just refuses to do so now

MicroTransactions wrote: ↑

Tue Feb 26, 2019 9:45 pm

Except it booted without issue two days ago, with the same charger. It has already run without issue with HDMI plugged in, but it now refuses to boot. Certainly, it's unlikely any of mine are specced correctly, but my Raspberry Pi has booted on considerably less before it stopped doing so. The Raspberry Pi has booted to a display since I got it, it just refuses to do so now

I'm afraid that "it worked before" doesn't exclude the power supply being the problem. I had a 3B which ran for a couple of weeks with no power issues on the (non-official) power supply that came with it, and then started having issues (including a flashing power light) which were definitively cured by replacing the power supply with an 'official' one. There had been no change, other than system updates, in the software running on it or the hardware attached to it.

Well, unless you dont change your mind about your underspecced power sources, your RPi will never boot properly....

its your choice now.....

MicroTransactions wrote: ↑

Tue Feb 26, 2019 8:53 pm

1. Yes, I did. Admittedly it's not best practice, but I can't see it causing anything outside of corruption of the SD card. It is also my only option for restarting if it has not actually booted
2. I'm using DD on Linux, with the following syntax

Code: Select all

sudo dd if=image_file of=/dev/sdh bs=1M

3. Running tvservice on a fresh install of Raspbian gives me

Code: Select all

state 0x40002 [NTSC 4:3], 720x480 @ 60.00Hz, interlaced

O.K., w.r.t. 2) what type of uSDHC card reader/writer are you using (built-in card "slot" or a USB-based device, historically the latter are more reliable)
W.r.t. 3. that suggests the Pi is booting but failing to detect the HDMI connection and so "falling back" to composite video mode.
Trev.

It boots without the HDMI in, although it seems to be picking up something, whether that's just what it defaults to some output mode. There's a possibility it is a power problem. As for the uSDHC card reader, I'm using the built-in one. I wasn't aware you could even use an external one during bootup

MicroTransactions wrote: ↑

Wed Feb 27, 2019 10:56 pm

I wasn't aware you could even use an external one during bootup

You can on certain models 3B+ included, but Trev was asking what kind of reader/writer are you using to write the image.

Right, still won't boot up even with official PSU. The reader I'm using is a front-panel reader/writer attached to a desktop.

So, my R-Pi 2B+ boots just fine with the same PSU, power-supply and display. Definitely something wrong with the Pi 3. How do I go about getting it replaced?

You know what, screw it. I'll just use it for something else and buy a new one. Guessing I must've managed to expose it to some static electricity, which has in turn shorted the HDMI connector to ground.

Have you tried the new SDCard in another Pi?
It is possible that you PC's built-in SDCard reader/writer is not SDHC compliant, so the image on the card may not be correct.
If it works on another PI, that is not the problem.
If it doesn't, try a USB SDCard writer before condemning the Pi3B+.

The test I mentioned earlier used the same SD card. The SD card reader I have should be full compliant with standards, I've never had issues with it before. So, yes, the SD card works in my other Raspberry Pi.

MicroTransactions wrote: ↑

Tue Feb 26, 2019 9:45 pm

Except it booted without issue two days ago, with the same charger. It has already run without issue with HDMI plugged in, but it now refuses to boot.

HDMI preventing booting. Not sure if there's any correlation -

https://www.raspberrypi.org/forums/view ... 7#p1437544