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AMS S-DMX repetitive Clicks in output problem Signal Splitters (HW)
Old 20th March 2016
  #1
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AMS S-DMX repetitive Clicks in output problem

Hello everyone,

Well, this is my first post Yay !!

And its about a problem ...

I searched for a similar problem in the forum but didn't came across anything.. so here it is:

My AMS SDMX has a problem, the output B is emitting two successif clicks every 6 seconds or so... and it is loud enough to be a problem...



The unit is in amazing condition, only one input pots needs to be either changed or cleaned, but its on the other channel, so its not related.

I know David Kulka is the man for these, but I am really worried sending the unit to LA... Im from Paris, France.
I know Neve UK is now servicing those units as well, but i have the same issue with shipping a rather fragile looking unit (the case is insanely sturdy but there's so many cards inside, Im worried about the handling of parcels by post)

I have a good tech here but he has never worked on those before...

So any idea on the fault/issue/fixing would be highly appreciated !

Thanks for reading !!
Old 21st March 2016
  #2
Deleted 3cb98a6
Guest
Tried turning off the metronome?
Old 21st March 2016
  #3
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Quote:
Originally Posted by Deleted 3cb98a6 View Post
Tried turning off the metronome?
Thats a funny one

I will also consider non-funny contributions !

Merci
Old 21st March 2016
  #4
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Hi
These were shipped OK when new so should be OK now although it may be good to ask AMS if it is best to add extra padding etc.
It may be duff memory or other simple fault but you would need spares to try things out.
Matt S
Old 21st March 2016
  #5
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Hi Matt,


Thanks for the reply,

I guess you are right, I will look into it !
Now I have to work out how to stay clear of customs since its a repair job, I am assuming that it should be free of tax, but you never know with customs...

As for the memory, I maybe able to swap the cards around between channels to check if the problem follows ?

Any recommendations for such a test ?

Thanks heaps for reading !
Old 22nd March 2016
  #6
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nednerd's Avatar
 

Did you try cleaning the edge connectors and reseating the boards?
Is the fan running smoothly?
Old 23rd March 2016
  #7
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WOW !!!!

Thanks so much The Last Byte !!!

Didn't expect such help !!! I truly appreciate and thank you for the time in reading, thinking and writing !!!

Im on my way to work now, so I will do all those test and soundfiles tonight and check everything you said to look into !!

Brilliant way to start the day, its nice to see such help coming from far away in those grim times....

Merci beaucoup !!!

I will get back with soundfiles and details later on tonight !

have a great day / night !

Jp

Last edited by spazspaz; 23rd March 2016 at 12:48 PM.. Reason: Typo
Old 23rd March 2016
  #8
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OK, tests are done but I am not sure there is any difference between XTAL and VCO mode.

The thing is, the clicks are happening as soon as its turned on.
First, I recorded a square wave through input A - Output A, XTAL First then VCO (no clicks)
Then input B - Output B, XTAL First then VCO (clicks on both settings).

Then I recorded a vocal stereo in and out, and the clicks are on the left, I think i mismatched the input on the RME, but in any case, it still the B side that clicks (which should have been on the right side...)

I left a bit of silence before each file so that the clicks can be heard first, then the square or vocal.
The clicks happen pretty much every 6 seconds...



As you can hear, its not so loud compare to program material, but in the case of quite sparse material, the clicks are audible and creates problems, specially on headphone listening.

Now the details,
AMS SDMX, serial: 4959, stereo in, stereo outs, 6 seconds on both channels, dual lock in, the boards where checked in Feb 1990, looks like its the built date.
the boards looks clean, no leaked caps or battery but they have never been changed.
I will get my tech to change the caps and the battery and also the fan which doesnt always turn on...

Thats about all I can say at this stage.
Let me know if there is anything else I should check or test, I guess my gut feeling is that its the output card since its only on one channel and when you turn the input B level off, you still have the issue, but I don't know anything about the architecture of this amazing machine, so my gut feeling is that I have no clue really......

thanks again for your help, its really nice of you !

Best from France

Last edited by spazspaz; 24th March 2016 at 12:00 AM.. Reason: Typo
Old 24th March 2016
  #9
Quote:
Originally Posted by nednerd View Post
Did you try cleaning the edge connectors and reseating the boards?
Is the fan running smoothly?
Edge connectors was my first thought. I'm no tech but this is what we used to do when that happened. I can't remember it not working!
Old 24th March 2016
  #10
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Thanks !

What do you mean by edge connectors ? do you mean the cards connectors ?
If so, how would you clean those connectors ?
Thanks a lot !
Old 24th March 2016
  #11
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Quote:
Originally Posted by psycho_monkey View Post
Edge connectors was my first thought. I'm no tech but this is what we used to do when that happened. I can't remember it not working!
Yep, cured my units more than once.

Pull the cards and clean the gold plated edge connectors on the cards.
Also check the cause connectors on the mainboard that hold the cards for bend
contacts, blow them clean with pressured air and clean them with alcohol. It's a bit tedious but possible. Reseat the cards firmly. Pulling and reseating them several times might also help.

If the fan is faulty, the damaged motor could potentially cause clicks by inducting peaks into the audio path...
...or worst case, the idle fan it could have caused an overheating of the unit and fried some components.
Old 24th March 2016
  #12
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Ok, I understand, and I will carefully try to do this, but to be honest, the cards are so well seated in those connectors, I find it difficult to even remove them...

The Ram cards are easy to pull, but the ones with two connectors are kinda not moving...

Any tips on how to approach the removal ? Im pulling from both side gently but its tight ! I really dont want to mess it up even further...

Cheers
Old 24th March 2016
  #13
Quote:
Originally Posted by spazspaz View Post
Ok, I understand, and I will carefully try to do this, but to be honest, the cards are so well seated in those connectors, I find it difficult to even remove them...

The Ram cards are easy to pull, but the ones with two connectors are kinda not moving...

Any tips on how to approach the removal ? Im pulling from both side gently but its tight ! I really dont want to mess it up even further...

Cheers
It's been a while since I've done this - but if you're in any way hesitant, please employ an experienced tech. It's too expensive to mess up!
Old 24th March 2016
  #14
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Yes you are absolutely right !
I will order a fan and caps today and book a job next week for replacement of those parts, get the connectors cleaned as well as the gold edges.

If you guys have any thought for my tech to investigate while its on his bench regarding that clicking sound, that would be amazing, but in any case, thank you all for your kind and generous advice and tips !

all the best
Old 26th March 2016
  #15
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Quote:
Originally Posted by psycho_monkey View Post
It's been a while since I've done this - but if you're in any way hesitant, please employ an experienced tech. It's too expensive to mess up!
I am in total agreement here. Best a Local Tech do the clean up, and any major Fault Finding is Sent to AMS/ SE as they keep most units, not all versions, though they do have test Jigs etc. just be prepared for € a month short on Euros!

Cheers
TLB
Old 26th March 2016
  #16
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I am speechless !

Thank you so so much for your time writing all this ! Incredible !

I will pass this to my tech and and get him to do all you said and then If its still there, I will ship it to AMS, I don't want to take chances with this !

I will update when I have some info, but yeah, thank you heaps !

Have a brilliant week-end

Best Jp
Old 26th March 2016
  #17
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With all due respect some of the "advice" here makes me very nervous. I strongly doubt that the crystal has anything to do with this. Cyclic digital problems are extremely common on these units and can be caused by any of the digital boards except maybe the CPU. If all the RAM cards are the exact same type (they probably are) you can swap between the two channels and see if the problem moves. (You probably have 4 DM69 RAM cards, the 2 A channel cards will be on the left.) Best case scenario is that one of those is bad, if that's the case you can look to get it fixed or do a repair/exchange with us.

I would definitely not pull all the cards and go through that whole cleaning and inspection regimen. You are just likely to make things worse. No matter how careful you are it's incredibly easy to get something swapped or damage a ribbon cable, and there's probably nothing to see anyway.

In the end it's probably going to be a bad ribbon cable or a bad MCB, effects extender, or pitch change board, or some combination of that. Nearly impossible to identify or troubleshoot these things on your own without spares and experience.

At least half the AMS gear that we get in for service has multiple problems and in many cases, the "extra" problems were caused by someone way out of their depth attempting their own repair. A unit with 2 faults generally takes at least 3 times as long to repair as a unit with 1 fault, because simple one for one card swaps won't make the unit functional, it will just change the symptoms. So please don't just start unplugging ribbon cables and PCB's.

Sorry to be all cynical and negative but this is awfully tough to do on your own. Make sure the ribbons and cards are tightly seated, and try swapping RAM cards, but there's not much more you can do on your own that is likely to be successful and again it's very easy to make things worse.
Old 26th March 2016
  #18
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Hi David,


Thank you for the reply,

I am all very confused about what I should do, but I will just a new fan, change the caps in the PSU and then get the ram cards swapped around and thats about it.
Then if the swapping around doesn't help I will get back to square one and look at repair options.

Thanks so much

Have a nice day

Jp
Old 27th March 2016
  #19
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Your problem won't be caused by PSU caps but new ones might be nice. Be careful about that too though, because it's easy to break the foils beneath the 5v switcher PCB without realizing it. You need to be careful when removing and re-installing the switcher PCB too, some of the hex nuts will have little plastic insulating washers, be sure to put them back where they were originally.
Old 27th March 2016
  #20
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Hey JP,
As David Has popped up, I'll ask that you Defer to David's advice as I have no doubt David will Keep the thread going with his Studio Electronics Expert AMS DDL and Reverb advice. Perhaps Robin might Pop up as well and even Steve from Bendon Tech, I'll keep watching with interest, though as I really only Fix my own and Professinal friends FX units it's best I just sit on the side lines and leave the Super Diagnostics to the "Professionals" !

Best Of Luck, I'm certain it's an easy Fix!

Regards
TLB

P.S

I would be curious to know if you're AMS-SDMX has "TimeFlex" as an SDMX with "XTAL and TimeFlex" thus Pitch Board would be redundant, as TimeFlex replaced XTAL though....many an AMS unit has had may different board options installed more so as "Upgrades" we're nearly custom suited to the user requirements allowing even RMX boards to be Installed etc. Though David is well aware of these type options as are Robin and Steve!

Cheers
J.
Old 17th April 2016
  #21
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Space Station's Avatar
Hey Spazspaz, if you get stuck I don't mind having a look for you. Sounds like a ram problem or some configuration error. I'm in the UK.
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