power supply problem with -15V

• ephy

  Posts 6

  Joined: Jun 13th, '16, 21:46

  Sep 6th, '16, 13:45

  Dear peoples,
  
  I got a strange problem after finishing the power supply part. I got only 0.5V on C91, then the 7915 can't deliver -15V..
  I replaced almost every components for be sure this is not a bad serie problem ( all comp are new from mouser ).
  
  for +15V i got only 13.45V
  for +5V i got 4.97V
  
  Is someone have an idea ?
  
  Thanks a lot,
  
  BR,
  Guillaume.

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BedroomMusic

Posts 134

Joined: Jan 7th, '16, 22:26

Location: Poland Katowice/Sosnowiec

Sep 6th, '16, 14:01

maybe you have Dc power supply? ou need Ac

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hofmann25

Posts 268

Joined: Jan 26th, '16, 21:30

Oct 11th, '16, 22:28

d-wreck wrote:Documented this issue for future generations because I goofed too. D'oh!

hey d-wreck, your build guide and helpful hints are the best! Thank you

BUT, I see you have noted "When shopping for a power adapter, ensure the data sheet explicitly states say 16V AC."
http://derek.trideja.com/nava/pages/nav ... -i-o-board

The e-licktronic says 15VAC. "The only component that you must get is a 15VAC supply 1000mA". http://www.e-licktronic.com/en/content/ ... -909-clone
And http://www.e-licktronic.com/en/content/ ... wer-supply "Plug your 15VAC 1000mA wall wart transformer to the IO board"


16VAC OR 15VAC???

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d-wreck

Posts 24

Joined: May 22nd, '16, 19:40

Oct 11th, '16, 23:42

Hello,

Glad you found my documentation useful. Other, much smarter people have said 16VAC is fine for Yocto. (Sources: [1] [2] [3])

The Yocto power board build instructions say "The transformer must be a 15VAC or 16VAC 1000mA.", and the Yocto power board seems quite similar to the Nava power board. Standard disclaimer: I know nothing about electronics and gave up on my Nava last week.

I can personally confirm that my Nava's voltage regulators have not blown up, and my transformer is 16VAC.

I'll update my documentation to include these bits.

Good luck!

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