ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Jonathan Goodall on September 22, 2013, 01:16:56 AM

Title: Fader issue on a Presonus 16.4.2
Post by: Jonathan Goodall on September 22, 2013, 01:16:56 AM
Hi, I got asked to have a look at an issue at a local church today.
Just over 12 months ago (so just out of warranty  ::) ) they purchased a new Presonus 16.4.2 and it has worked well for their use, but today a channel wouldn't turn off when the fader is pulled down to infinity (ie still passed audio to the main outputs).
I had a look on the  UC software and offending channel showed the fader being at just under unity even though it was right down on the desk. 
If you move the fader on the desk to the -60 position (a movement of about ~3-5mm), the fader on the UC dropped to infinity and audio stopped passing to the main outs.
 Any movement above that point results in the fader postion on the UC jumping back up to almost the unity position and rapidly jittering up and down as you slowly raise the physical fader.
 As you pull the fader back down the reverse happens (UC fader jitters rapidly up and down until you reach -60 then drops to infinity until the physical fader reaches infinity at which point the UC fader jumps back up to ~ Unity).
At this point in time troubleshooting digital desks isn't my strong point but I did try doing a Factory reset which didn't help the problem and I am fairly certain the firmware was up to date and the faders are not set to lock-out.
If it was an analog desk I would suggest that the fader was dodgy but can anyone suggest any other things I may have missed?

Cheers, thanks for your time  :)

(PS I tried searching the Presonus site and a few fader issues popped up but not quite like this one.  Also for some reason I don't seem to be able to register to ask a question on their tech support thread)
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Tim Perry on September 22, 2013, 04:40:26 AM
The fader is broken. It is not a "digital" problem.

Kudos for the comprehensive explanation of the problem.

It might be dirt or gunk from a spill.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Jonathan Goodall on September 22, 2013, 05:04:37 AM
Thanks for the reply.
I might try blowing some canned air through the fader and see if it helps,  just in case (no sign of any spillage) but it looks like a trip back to the suppliers is in the wind.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Bob Leonard on September 22, 2013, 09:13:20 AM
Canned air on faders can make the problem worse by driving and spreading the dirt or foreign object deeper into the fader. Use some cleaner and a shop vac. Spray the cleaner into the fader, put the vac hose over the fader knob and slowly slide the fader up and down with the vac turned on.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: John Roberts {JR} on September 22, 2013, 09:28:06 AM
It may be a bad solder connection.

JR
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Mike Sullivan on September 22, 2013, 09:46:58 AM
I had the exact same issue with Ch. 3 on my 24.4.2.  Seems to have worked itself out now, so it may just be dirt/debris.  Originally, mine was having issues being read, so the sensor would have the fader jump around quite a bit, then it would do the same thing you're doing...checked it a few weeks ago, no issues like that anymore (it was being weird, coming up when I brought the Ch 2 fader up a bit), but checked it today and I'm not having any issues anymore.  May just need a good cleaning.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Chuck Simon on September 22, 2013, 09:53:58 AM
You may have a bad fader.  Put in a service ticket with Presonus.  You will get a response wthin 24 hours.

http://support.presonus.com/home.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Jonathan Goodall on September 22, 2013, 06:41:10 PM
Canned air on faders can make the problem worse by driving and spreading the dirt or foreign object deeper into the fader. Use some cleaner and a shop vac. Spray the cleaner into the fader, put the vac hose over the fader knob and slowly slide the fader up and down with the vac turned on.

By cleaner, do you mean something like Caig Deoxit? (Which I have)

Thanks
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Stu McDoniel on September 22, 2013, 07:59:42 PM
By cleaner, do you mean something like Caig Deoxit? (Which I have)

Thanks
You had better use what the service manual for that model tells you to use.  With faders there is lubricant involved as well as cleaning.
If you are not sure what to use then do not attempt this.
Contact the manufacturer Jonathan.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Tim Perry on September 22, 2013, 10:08:27 PM
By cleaner, do you mean something like Caig Deoxit? (Which I have)

Thanks

quote from a Presonus tech "Presonus doesn't recommend the use of anything but low pressure dry air"

Deoxit may provide a short term fix, but like a junkie, it soon wants more.

Sometimes the resistive film is simply worn out and no amount of spraying will be productive.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Chuck Simon on September 22, 2013, 10:19:36 PM
Presonus has very good tech support - use it!
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Jonathan Goodall on September 22, 2013, 11:39:04 PM
I have talked to the dealer that the desk came from, and before I had finished explaining the problem they were telling me what they thought was wrong.
They think it is a bad solder joint (to the earth I think he said).
Once new parts have arrived the desk will be sent in for repairs.

Thanks for all the feedback.

Cheers :)

Title: Re: Fader issue on a Presonus 16.4.2
Post by: Paul Poadak on September 23, 2013, 07:16:15 PM
I just sent my SL 24.4.2 back with similar issues. I was told all repairs are receiving new faders with improved dust covers. Don't delay, just call for an RA and send it in. They are a pleasure to deal with.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Mike Diack on September 24, 2013, 08:05:09 PM
I have talked to the dealer that the desk came from, and before I had finished explaining the problem they were telling me what they thought was wrong.
They think it is a bad solder joint (to the earth I think he said).
Once new parts have arrived the desk will be sent in for repairs.

Thanks for all the feedback.

Cheers :)
Assuming the SL has been bought from Oceania, Nigel will source the faders and I will fit them.
Even though the unit is out of warranty, the parts and labour cost is not huge (SOMETHING had to be compromised making a mixer with these features for not much money). Rare is the week I don't have an SL in the workshop for new faders. BTW you can fit Alps "K" series faders into these things and they will last forever.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Alec Spence on September 25, 2013, 09:42:39 AM
So, they avoided moving faders for cost issues and then *still* went bottom dollar - the mind boggles!

Will be interesting to see if the X32 faders end up being a ton more relieable than the non-moving ones from the SL!
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Mike Diack on September 26, 2013, 03:54:18 PM
So, they avoided moving faders for cost issues and then *still* went bottom dollar - the mind boggles!
Yup - got it in one. Bottom of the line Taiwan Alpha. The only thing I've seen with worse faders is the little JBL "Musicmix" that came out with the original EONs (AKA Fisher Price "My First Mixer").
M
Title: Re: Fader issue on a Presonus 16.4.2
Post by: John Roberts {JR} on September 26, 2013, 04:27:39 PM
Yup - got it in one. Bottom of the line Taiwan Alpha. The only thing I've seen with worse faders is the little JBL "Musicmix" that came out with the original EONs (AKA Fisher Price "My First Mixer").
M
Lets not forget that one science fair mixer where the pots were screened onto the PCB.

I recall one very early cheap brit mixer that used rotary trimmers for audio controls. 

Then there's the Jung Poon hand grenades that would break if you looked at then cross-eyed. Those motivated Alps to made their affordable K(orean) fader, before that the cheapest Alps fader that didn't suck was several dollar more each.

Faders are always a difficult design decision. Easy to second guess after the fact. I lost one argument with the guy who's name was on all the buildings about which fader to use in my last big recording board. Hint: I wanted to use the expensive Alps (before the K fader was available).  Alps saved my ass, when they introduced the K fader. 

JR
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Bob Leonard on September 26, 2013, 09:12:31 PM
So that's what non motorized really cheap faders look like. You know JR, Alps spelled backwards is spla.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Samuel Rees on September 26, 2013, 10:00:40 PM
Definitely not the first fader issue I've seen on Presonus desks. Not super robust faders at all.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Chuck Simon on September 26, 2013, 10:41:01 PM
You know, using the iPad app, I have barely touched my faders on my SL in the last year!  When I have, they seemed to feel pretty good compared to what I have used in the past.  I'm not really worried about it.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Tim Perry on September 26, 2013, 11:04:19 PM
You know, using the iPad app, I have barely touched my faders on my SL in the last year!  When I have, they seemed to feel pretty good compared to what I have used in the past.  I'm not really worried about it.

No problem with faders here.  I even survived a very wet outdoor summer season.
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Jonathan Goodall on September 26, 2013, 11:16:05 PM
Assuming the SL has been bought from Oceania, Nigel will source the faders and I will fit them.
Even though the unit is out of warranty, the parts and labour cost is not huge (SOMETHING had to be compromised making a mixer with these features for not much money). Rare is the week I don't have an SL in the workshop for new faders. BTW you can fit Alps "K" series faders into these things and they will last forever.

I sent Nigel an email not long ago lol.
I checked  all of the others as requested and only the one seems to have any issues.   I did try running some low pressure air over it (as suggested, no cleaner) and the problem is not now as bad as it was, but not cured either (still jitters around on UC but will track with the fader to certain extent).
Title: Re: Fader issue on a Presonus 16.4.2
Post by: Bob Leonard on September 27, 2013, 10:40:08 AM
I sent Nigel an email not long ago lol.
I checked  all of the others as requested and only the one seems to have any issues.   I did try running some low pressure air over it (as suggested, no cleaner) and the problem is not now as bad as it was, but not cured either (still jitters around on UC but will track with the fader to certain extent).

If your sure it's bad it won't hurt to try some cleaner and the vac as I mentioned above.