Basic Troubleshooting

Basic basic basic!

PRAM/SMC reset first!
Remember to try booting in Safe Mode by holding left shift key during boot.
Have the proper tools ready and available - known good/functional spare parts, Shiny diagnostic boot drives, external monitors, proper adapters, known good keyboard/mouse, etc. ALWAYS have good bits in your kit! Periodic inspections and requesting replacements when needed is a must!
Instructions for malware cleanups, basic terminal commands, SAVE LINKS AS FAVORITES for good instructions, wikis, etc. for easy reference.
Utilize manuals and forums in Zoho!

Is Mac turning on at all? Check for sounds (fan, chime). Check MagSafe light - is it green/amber?
Check for response from the Caps Lock, which should respond if the system is up and loaded. If does, it is most likely a damaged screen.
- If Mac is booting (chimes, signs of light, but no display), check to see if backlight is bad by shining a flashlight through the Apple logo on the other side of display. If you see a picture on the front of display where the light is shining in (login screen, desktop, loading progress bar, etc.), the backlight is bad and logic board repair/replacement should be considered.
- If there are no signs of life, open bottom cover and check for liquid damage - corrosion/residue on logic board, cables, connectors, inside bottom cover, flex cables, etc. Check for abnormal smells or fried components. Check to make sure RAM is properly installed (can be displaced if dropped or hard bang).
  - Disconnect all connectors (starting with the battery first ALWAYS) and see if any signs of life after everything is disconnected. If shows life, power down and reconnect one cable at a time (powering down before connecting each cable) until you can pinpoint what is causing the issue. If still no signs of life, logic board repair/replacement should be considered.
  - Check keyboard and hard drive (if either are bad, they can cause no boot in some models).

- Retina/Air models - a bad trackpad and/or trackpad cable can cause the keyboard to no longer function. Test with known working trackpad/cable and confirm issue.
- If some keys are functional and others are not - check for evidence of liquid damage (inside Mac, keyboard connector, keyboard flex, sticky/crunchy feeling keys when typing, etc.). If it is a Mac with butterfly keyboard (newer models), check model number and see if it qualifies for Quality Repair Program through Apple (if no liquid damage is present).
- Check with known working keyboard and see if issue is resolved.
- Check for software issue - log in as another user or Guest and see if issue is still present. If issue is not present under different user, log back into original user and check Accessibility settings to make sure “Mouse Keys” is not enabled in the “Mouse & Trackpad” section. Check for malware or other applications which may interfere.

Try SMC/PRAM resets.
Open Mac and inspect for liquid damage.
Disconnect batter and use genuine 85w MagSafe - does Mac boot automatically without pressing power button?
Remove existing battery and replace with fully charged, known good battery and try to boot.
Follow similar troubleshooting steps as mentioned above in display section - disconnecting all connectors from logic board and connecting one by one.
Disconnect battery and keyboard and try power on pads (non-retina models - instructions can be found here.
Check keyboard (power button attached) - try with known good keyboard.
Check DC board - try with known good board.
The following components are sometimes a cause for no power: bad keyboard, bad SSD, bad DC in board, bad DC in board flex cable, bad trackpad, bad trackpad cable, RAM not properly inserted or bad (you do not always get RAM beeps in some situations).

Mid-2012 non-Retina - 13” A1278 models - LCD flickering and system freezing due to defective lower RAM slot. Solution would be to run with one stick of RAM in good slot or replace logic board.
2011 27” iMac and 15”/17” MacBook Pro models - AMD GPU failure - Symptoms include no boot, discoloration/vertical lines/artifacts, glitching, freezing during loading, rebooting, or gray screen. Other symptoms may present as well not listed here, but these are the common ones. Run GPU test to confirm issue if possible. The only model we can currently fix is the 15” MacBook Pro. We can replace the logic board with a 2012 15” MBP logic board. There are no fixes for 27” iMac or 17” MacBook Pro.
2012/Early 2013 15” MacBook Pro Retina - Power buck issues - Will not fully boot/black display - logic board repair is required.
Late 2013/Mid 2014 15” MacBook Pro Retina - black outs/random shut downs - CPU power state issue - logic board repair required.
2008/2009/2010 15”/17” MacBook Pro - Kernel panic due to bad component on logic board - logic board repair is required.
2015 MacBook Pro Retina 13” - Track pad cable defective causing no boot.
2012 MacBook Pro non-Retina 13” - Hard drive cable defective - symptoms include (but not limited) a prohibitory symbol or folder with question mark when starting up, slow drive, freezing at loading bar - confirm by booting into diagnostics drive and checking for CRC errors in Drive DX.