Hello Bill,
Hi this Pi no longer will Boot from any SD card for any Pi OS distribution.
Reformatting the SD cards has no effect and writing the OS fails to read much less boot it.
Let's start with basics:
? 1. Is this an existing SD card or new SD card?? If it's an
existing SD card, please note that depending how you were using it,
they can and WILL go bad.? I would recommend to try a NEW brand-name
SD card like a real Sandisk card from a known trustable source.
? 2. What tool are you using to write the SD card?? It's possible to
create non-bootable SD cards.
? 3. Are you sure you have a very solid 5.1 volts into the Raspberry
Pi.? Check the voltage on the correct GPIO pins using a volt meter
The Red LED is lit for power indication but the Green never lights.
On the HDMI display, what do you see?? Do you see the Raspberry Pi
rainbow color display??
There are no accessories installed on the PI.
I¡¯ve tried the boot loader nothing helps.
Are you thinking of the Raspberry Pi 4 boot loader?? If so, that
won't work as the Raspberry Pi 3B+ hardware doesn't use it.
Is there a secret back door to get into the EPROM or something? Maybe accessing it from Windows 10?
As mentioned above, there isn't any boot eeprom on 3B+ units and
there aren't any published diagnostic documents of how you might
troubleshoot the hardware per se.? There are a TON of Internet
search hits on "Raspberry Pi 3B+ won't boot" that you can follow up
with.? Some might be helpful but most will say the same things I
just said above.
Looks like this is now a paperweight
All hardware does fail in time.? Maybe ESD got it.. maybe a power
surge got it.. maybe it's just it's time but it's most likely a
failed SD card or power supply.
--David
KI6ZHD
