kaktus' guide - fans - appendix
https://www.geeetech.com/forum/viewtopi ... 27&t=60914
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GT2560 Rev A+ Board Voltage regulator issue
Re: GT2560 Rev A+ Board Voltage regulator issue
I think you should check if the interface on the fan is short-circuited.Oaken3d wrote: ↑Sat Mar 17, 2018 10:20 amHaving same issue, i have 2 gt2560 A+ and im unable to use 2 fans, if i connect 2 fans the Voltage regulator (7812BG) gets crazy hot in only few seconds, if i disconnect the fans everything works good, if i connect just 1 blower same problem. I try disconnecting everything even removing the steppers drivers and same issue connecting just the fans. I have exactly same issue in the two boards, i try to put a small heat sink but doesn't work, heat sink gets hot in 30 sec.
Also, pay attention to whether Q5 is normal
Q5:AP2306AGN
-Keep your mind and try to test it. 
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-Everything will be fun！-Support all Getech printer.
-You can ask me the questions and I will kindly reply.
-Respect others is the best way you can get help!
Re: GT2560 Rev A+ Board Voltage regulator issue
[quote=Oaken3d post_id=83215 time=1521253243 user_id=64742]
Having same issue, i have 2 gt2560 A+ and im unable to use 2 fans, if i connect 2 fans the Voltage regulator (7812BG) gets crazy hot in only few seconds, if i disconnect the fans everything works good, if i connect just 1 blower same problem. I try disconnecting everything even removing the steppers drivers and same issue connecting just the fans. I have exactly same issue in the two boards, i try to put a small heat sink but doesn't work, heat sink gets hot in 30 sec.
[/quote]
The BG voltage regulator Features: Output current up to 1.5 A, Thermal overload protection and Short circuit protection and I believe that its supplying 5V to the system.
Sounds like a 12v feed from the fans is being supplied to the 5v regulator, the fans are 12V so why have a 5V issue?
The GeeeTech fans state 12V 0.09A, I just measured one at 12V with a regulated supply and it's actually 0.11A but no big deal.
Suggestions:
Test the fans with a 9v battery to establish the correct wires (+ - and sense if applicable) they should run - mine turn with 3v
Check the connectors - Use jumper cables to connect to the fan to the board - do not connect sense - ensure + and - are correctly set
Only a suggestion but use power supply VMOT 12V and GND of stepper driver socket to power the fans if you still have issues
Having same issue, i have 2 gt2560 A+ and im unable to use 2 fans, if i connect 2 fans the Voltage regulator (7812BG) gets crazy hot in only few seconds, if i disconnect the fans everything works good, if i connect just 1 blower same problem. I try disconnecting everything even removing the steppers drivers and same issue connecting just the fans. I have exactly same issue in the two boards, i try to put a small heat sink but doesn't work, heat sink gets hot in 30 sec.
[/quote]
The BG voltage regulator Features: Output current up to 1.5 A, Thermal overload protection and Short circuit protection and I believe that its supplying 5V to the system.
Sounds like a 12v feed from the fans is being supplied to the 5v regulator, the fans are 12V so why have a 5V issue?
The GeeeTech fans state 12V 0.09A, I just measured one at 12V with a regulated supply and it's actually 0.11A but no big deal.
Suggestions:
Test the fans with a 9v battery to establish the correct wires (+ - and sense if applicable) they should run - mine turn with 3v
Check the connectors - Use jumper cables to connect to the fan to the board - do not connect sense - ensure + and - are correctly set
Only a suggestion but use power supply VMOT 12V and GND of stepper driver socket to power the fans if you still have issues