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Zedboard LEDS on power up, board not booting

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reddragon's picture
reddragon
Junior(0)
Zedboard LEDS on power up, board not booting

Hi!
I left my Zedboard plugged in over night, switched of the supply and expected a fine, working device the next morning.
However, something must have happened over night - when i flick the power switch, the power-on LED does not light up, while all LEDs LED0 to LED7 are red.
 
The power supply itself seems to work fine and fuse F5 is intact - any ideas on what might have happened and how i can fix that?
 
Best
 
Mike

JFoster's picture
JFoster
Moderator(48)
Hello Mike,

Hello Mike,

You say somthing different in this post. Could you please clarify what happened. Thanks

http://zedboard.org/content/zedboard-lpc-connector

--Josh

reddragon's picture
reddragon
Junior(0)
Hey Josh!

Hey Josh!
 
Thanks for your reply - both posts are unrelated to each other. The Zedboard i'm refering to in this question was running fine for months now, but now, all of a sudden, "something" seems to have happened. Any ideas? There were no power anomalies (we keep track of surges and stuff) and i switched of the power as i do every evening. It does not boot and i have no clue why...
 
Best,
 
Mike

JFoster's picture
JFoster
Moderator(48)
Hello Mike,

Hello Mike,

Could you try a different power supply/outlet. When the power good LED is not enumerated, the board prevents operation. If that doesn't help. Try measuring all your Power Rails on the board and report back the results. See Table 19 of the Zedboard Hardware User Guide http://zedboard.org/support/documentation/1521 for information on where the power rails are located and what they should be.

--Josh

reddragon's picture
reddragon
Junior(0)
Thanks Josh, already looked

Thanks Josh, already looked at one of your older replies in a different thread where you've suggested exactly that. The board is already fixed and works as if nothing happened :)
I'd like to share my procedure in case someone might have a similar problem:
* download the Hardware User Guide (HWG) and the Schematics (for me, Rev D.2)
* look at Table 19 of the HWG  and open Schematics page 11

  • all voltages listed in Tab. 19 can be measured by looking up the capacitors/resistors on page 11
  • look up the desired voltage, choose a capacitor/resistor and look for it's label in the star-shaped Cap/Res arrangement next to the ZynQ

* if all voltages seem to be OK OR if VADJ is the only issue, go to page 16 of the schematics document

  • locate the LM339 on the board and measure the comparator inputs and their corresponding outputs (PG-ALL, PG-1V0 and PS-POR-B)

NOW - VADJ was my only issue, so I did the following:

  • measure comparator 4 (IN4+ and IN4-) on the LM339 - if  IN4+ < IN4-, then PS-POR-B will be low (obviously) and prevent the FPGA from booting.
  • Go to page 15 of the HWG and look at the MAX15021ATI+, which controls the VADJ - locate that device on the board (below the VADJ jumper/header on the board)
  • measure VADJ on C340 - if VADJ is roughly 0V and you're unable to replace all the components of that circuit, simply solder a piece of wire to L3 (pin connected to C340) 
  • apply the voltage set at the VADJ jumper - be careful with the current. I turned the current limit on my power supply to zero and slowly ramped up the current AFTER the Zedboard was already powered on.
  •  The POWER-LED will light up and the board will boot as usual.

Thanks for your help Josh,
Mike

Zlatan's picture
Zlatan
Junior(0)
Hello Mike,Can you help me?

Hello Mike,I am a postgraduate in China,my English is poor... i just try my best to descript my situation. have the same problem with you,i pull the shorting stub in VADJ Select 2V5 when the SDK is working,then all the LEDS lights,and i am puzzled about what you say"solder",i don't know how to solder... can u help me?

JFoster's picture
JFoster
Moderator(48)
Hello Zlatan,
JFoster's picture
JFoster
Moderator(48)
Hello Mike,

Hello Mike,

I am happy you found your solution! Thank you for sharing it with the community.

--Josh