{"id":772,"date":"2012-12-15T22:15:34","date_gmt":"2012-12-16T06:15:34","guid":{"rendered":"https:\/\/www.ussherpress.com\/blog\/?p=772"},"modified":"2017-03-08T20:18:58","modified_gmt":"2017-03-09T04:18:58","slug":"debugging-raspberry-pi-power-issues","status":"publish","type":"post","link":"https:\/\/www.ussherpress.com\/blog\/?p=772","title":{"rendered":"Debugging Raspberry Pi power issues"},"content":{"rendered":"

I recently tried out Plan 9 for the Raspberry Pi<\/a>. I tried it for all of 5 minutes and got bored and left my RaspPi plugged in. When I came back a couple of hours later, the Pi was powered off with no LEDs turned on. What’s more, it smelled like something was burning and the board seemed a little hot.<\/p>\n

\"\"<\/a><\/p>\n

I unplugged the thing and plugged it back in, but it wouldn’t boot up. None of the LEDs would light up.<\/p>\n

This was a learning opportunity, so I decided to debug it. There is a lot of good info online for debugging power issues on the Raspberry Pi<\/a>.<\/p>\n

Apparently, there is a fuse next to the USB power input that could possibly open up if too much current flows into the Pi. Since I was doing the non-recommended thing and powering my Pi with the USB port of my PC, I figured maybe that was it. I measured the voltage across the fuse (known as component F3 on the board) and found 4.3V in and 3.9V out. That’s a significant drop.<\/p>\n

According to this page<\/a>, if you have a significant drop in voltage across the fuse, it’s likely open (or blown). The fuse auto-resets itself, but just needs some time, so one option is to leave the device powered down for a few hours, or days, and see if it works then.<\/p>\n

In my case, I left it for a few days and it still wouldn’t work, so I figured the fuse must be blown. However, I figured the input voltage of 4.3V was itself too low, so I tried ordering a new USB power source. From watching a terrible video on YouTube (I won’t link it), I found out that Adafruit provide a nice little power source<\/a>. They also provide micro USB cables, so I figured maybe I should get another one and see if that helps.<\/p>\n

Today, I tried out the new power source and USB cable. I now read 4.7V in on the fuse and 4.38V out. The board still won’t power up. There’s still quite a drop, so I really think the fuse is bad.<\/p>\n

\"\"<\/a><\/p>\n

Next up: try removing the fuse and shorting the line. I’m no expert on this, but I’ve read that this is really not recommended since the fuse really does serve a purpose of ensuring you don’t supply an overcurrent. I’m going to trust my power supply is a good one and experiment.<\/p>\n

Long term, I’d still like to get a new fuse. Unfortunately, I visited a couple of local shops in the Seattle area and they didn’t have any of the surface-mounted resettable fuses, so I’ll have to order one online and wait for a few days.<\/p>\n","protected":false},"excerpt":{"rendered":"

I recently tried out Plan 9 for the Raspberry Pi. I tried it for all of 5 minutes and got bored and left my RaspPi plugged in. When I came back a couple of hours later, the Pi was powered off with no LEDs turned on. What’s more, it smelled like something was burning and … Continue reading Debugging Raspberry Pi power issues<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[81],"tags":[78],"_links":{"self":[{"href":"https:\/\/www.ussherpress.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/772"}],"collection":[{"href":"https:\/\/www.ussherpress.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ussherpress.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ussherpress.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ussherpress.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=772"}],"version-history":[{"count":10,"href":"https:\/\/www.ussherpress.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/772\/revisions"}],"predecessor-version":[{"id":1427,"href":"https:\/\/www.ussherpress.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/772\/revisions\/1427"}],"wp:attachment":[{"href":"https:\/\/www.ussherpress.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=772"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ussherpress.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=772"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ussherpress.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=772"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}