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An Appoge Big Ben Question from a novice

Discussion in 'Converters / Interfaces' started by Guelph_Guy, Aug 23, 2015.

  1. Guelph_Guy

    Guelph_Guy Active Member

    Okay, I've added the big ben as the master in my clock chain all appears to be good, a/d's are clocking and all sounds fine.
    So the question I have is that the blue 'narrow' led flickers periodically and not overly bright when it is stable, is this the default behavior?, I ran the led test and the led appears to be okay, The unit is well ventilated and cool to the touch..

    I'm just having a hard time being instilled with any 'confidence' when I see this behavior..

    Thanks in advance...
  2. audiokid

    audiokid Staff

    I don't have any experience with your digital tools so it's difficult to say if your clock will drift but if its clocking (everything connected to it are stable) and not making weird noises, chances are it's good at this point.

    Since you tested the led, I'm wondering about the PSU though. Does the LED brightness or stability change when less gear is connected to it or the chain?
    @Boswell . He is the man for this.
  3. Guelph_Guy

    Guelph_Guy Active Member

  4. Guelph_Guy

    Guelph_Guy Active Member

    Thanks for the reply, yes, I thought it might be supply related but even under no external load at the WC outputs, the issue is still there, I've been running it continuously for about 13hrs right now and no dropouts or digital hash noise, Might be a bad solder joint on the led, or somewhere on the display board.

    Power supply is pretty simplistic in the unit, not really to much to troubleshoot there, Unless there's some noise coming through the power supply that's affecting the ability to narrow lock, The supply appears to look okay, no swollen caps no burn marks or signs of component sweating. Anyhow, it will lock solid with the narrow led but the led appears very dim, perhaps its the led driver itself .. oh well pure speculation at this point

    Thanks for the reply
  5. Boswell

    Boswell Moderator Distinguished Member

    What clock source have you got selected on the Big Ben? Which LED(s) is/are lit in the PULL UP/DOWN field?
  6. Guelph_Guy

    Guelph_Guy Active Member

    Hi Boswell, thanks for getting back to me ... my clock is on "int"

    and my pull up/pull down is on "None"..

    I ran another led display test and the blue led is pretty dim ( after several hours of operation ( I had to cup my hand around the display to see if it was lit)

    I powered the unit off and powered it back on .. left the house for 45 minutes and now the blue led is lit solid ...

    I thought it might have been the ribbon cable between the display panel and the main circuit board , I re-seated it but no difference..

    Outside of this behaviour , I'm not having any issues

  7. Guelph_Guy

    Guelph_Guy Active Member

    Just to let you know this occurs on any clock rate...
  8. Boswell

    Boswell Moderator Distinguished Member

    Well, the suspicion is that when the blue LED is not lit solidly, the PLL is not locking correctly to the selected frequency source (internal crystal or external clock). This could be a PLL problem, in which case your output clock would be present but unreliable, or it could simply be a driver or connection problem in the LED circuitry and the output clock is good.

    Either way, I think it would be safe to assume that your output clock is OK when the LED is a solid blue.
  9. Guelph_Guy

    Guelph_Guy Active Member

    I think what I should try here is slaving the big ben to a different clock source and see if the PLL locks up. if it locks up and the blue light goes solid ,then it could imply there is a problem with the internal clock reference...

    Just trying to rule things out here...

    Thanks for getting back to me
  10. Guelph_Guy

    Guelph_Guy Active Member

    Well, I switched clock sources and slaved the big ben to another word clock ..... The problem is still there so it appears the PLL is not Locking up....

    However I just ran the led display test on the big ben and the narrow lock Blue LED is flickering too.. AARRGG!!!! frustrating to figure it out,

    well, the last ditch attempt will be to pull the display board and see if its a cold solder joint , if not I'll be calling Apogee .

    fortunately I don't have too much money in the unit as I bought it used..
  11. Guelph_Guy

    Guelph_Guy Active Member

    UPDATE ...
    Well as I had nothing to lose, I ripped into the unit ...

    Took the lid off
    unplugged the ribbon cable to the panel.
    removed the front panel from the chassis ..

    However, the display/control board is held in with very small torx screws, so I couldn't get it pulled out ..

    I eyeballed the approximate position where the blue LED should have come into the board.

    There were very small solder points on the board where the leads from the leds would pass through which appeared to be grey and not shiny so I decided to touch them up.

    I now have a bright blue light which is not flickering at all, and is the full brilliance when in test mode as in operation! :)

    So I'll run it up for another 10 hrs and keep an eye on it , only the PLL to rule out now..

    DonnyThompson likes this.
  12. Boswell

    Boswell Moderator Distinguished Member

    Sounds as though you have hit the spot. If the LED stays constantly bright blue, it's saying the PLL is OK as far as it is aware.

    Well done!
  13. Guelph_Guy

    Guelph_Guy Active Member

    Thanks Boswell, I used to be a communications engineer and a systems integrator, So pulling out the soldering iron was pretty easy , however , I can tell I'm getting older as darn those points were like surface mount small ! LOL

    anyhow , when the solder looks dull and dark , it can be a pretty good indication that it hasn't flowed properly.

    cheers and I appreciate your help.....
    pcrecord likes this.
  14. DonnyThompson

    DonnyThompson Distinguished Member

    Isn't it amazing in our craft how just one tiny piece of lead can screw up our entire world? LOL

    Glad to hear it worked out for you.

    Tell Guelph, Ontario that Donny from Ohio says hello. :)
  15. Guelph_Guy

    Guelph_Guy Active Member

    Hi Donny , sounds like you've been through our quaint little university town ....lol
    Actually you could probably hit a recording every city block here, there's more home studios then you can imagine,

    So when were you up our way ?

  16. DonnyThompson

    DonnyThompson Distinguished Member

    Many times... my ex wife ( still a great friend) was born in Guelph, and her parents moved to Wiarton., so we travelled thru there frequently to see her family. Guelph is a nice little town. It was also my obligatory Tim Horton's stop. ;)
  17. Guelph_Guy

    Guelph_Guy Active Member

    Wow, what a small world... who, would, have thunk,it lol

    Well I've been to, Dayton for an amateur radio hamfest and swap meet, but never to, Akron I'll, pencil it in...


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