Film-Tech Forum ARCHIVE: Sound problems USL JS105/195 processor

This is topic Sound problems USL JS105/195 processor in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=006030

Posted by Chris Liczbinski (Member # 1957) on 04-05-2004, 02:58 AM:

Hello all,
I have been a bit stumped with a recent sound problem in an auditorium. The sound processor in it is the JS 105/195 by USL, 2x JBL CS-400 amps (for left, center, right and surround) and one JBL CS-800 for the subwoofer. The left, surround and subs weren't working all of a sudden after a show Friday night, so I went through a few simple things just for reassurance, like:
buzz track - perfect
dolby tone - perfect
moved right channel 1/3 octave EQ card (model JEQ-10) to the left channel- left channel suddenly worked.
Tried two brand new JEQ-10's in the right and left channel and they did not work. The center EQ card works in every slot as well, but after trying 5 different known-good EQ cards in every channel slot I gave up trying to swap cards.

Surrounds- tried new surround EQ cards (3 spares)- still did not work. I tested them out by plugging the sound imput from another channel that was working into them and they worked.

I am getting good readings for every speaker and when I have either the original left or center EQ card in a channel slot that channel will play pink noise- so the amps and speakers are fine. I checked the resistance just in case and it verifies good speakers as well. The cables from the back panel of the JS 105/195 to the amps are good- (near 0 ohms).
Any comments or questions will be greatly appreciated! I possibly forgot to mention some bits of information so please ask away.

EDIT: forgot to add that I tried new preamp/matrix/format and powersupplies all to no avail.

[ 04-05-2004, 02:23 PM: Message edited by: Chris Liczbinski ]

Posted by Mark Gulbrandsen (Member # 72) on 04-05-2004, 08:30 AM:

Ots probably a bad format card. It is the most failure prone card that Ultra designed! It could simply be a dirty bypass switch, rip out and jumper it!, or the failure of some part. I've seen so may different modes of failure on these that I couldn't begin to list em all. One recent failure actually swapped two of the channels around [Eek!]

. I believe that all audio channels are routed through it twice. You can also bypass the output relays on the EQ cards as they are also prone to failure.

Hope some of this helps.

Mark

Posted by Gordon McLeod (Member # 33) on 04-05-2004, 08:58 AM:

Format board is the most likely
Is there a digital adapter hooked up to it and is it a problem for both analouge and digital and nonsync
If there is no digital adapter try connecting a external source to the digital input with a known signal and see if it flows through
Also I presume that you have a monitor that allows you to verify that the signal is not coming out of the processor and it isn't a dead amp or a wireing problem

Posted by Darryl Spicer (Member # 711) on 04-05-2004, 09:10 AM:

I guess it could be possable that you have a bad backplane mother board.

Posted by Chris Liczbinski (Member # 1957) on 04-05-2004, 12:36 PM:

First off, thank you for the advice and quick responce!
I tried two different format cards from other processors that were known to function in all channels- and it was a no-go.

Gordon- I do not have a monitor but I did swap wires around to where center was connected to the surrounds, or when the right and center channels worked, hooked the right channel output to the left speaker. Every channel worked just as it should so i assumed the amps were good as was the wiring. Just as a backup I checked resistance between the backplane and the amps, then from the amps to the speakers- all tested good.
All I can think of doing now is grabbing a few other format cards and trying those. I am blessed(?) with having 14 other projectors with the same equipment (except four run DTS on the JSX-1000-same format card though).

Mark- I have not been dealing with these processors or cards for too long- is there any way you could describe how to bypass the output replays on the EQ cards? As for jumping the bypass switch- you are talking about shorting it and seeing if it helps? I would of thought that jumping it would cause it to be in bypass?

Darryl- we have a spare backplane mother board and I thought about ours being bad but with the short leads the tech left us with when installing our equipment that would be the last thing I would like to switch- only thing I don't understand is how two EQ cards will work in every channel I slide them into but any other known-good card will not work??
This has been a real head scratcher for me!

Posted by Clint Koch (Member # 1179) on 04-05-2004, 01:21 PM:

Hello Chris,

Please call 805-549-0161 and ask for either myself or Mike Ringrose. We have questions and a few suggestions.

Clint

Posted by Mark Gulbrandsen (Member # 72) on 04-05-2004, 08:08 PM:

My expereince has been.......

1. Jumper the output relays
2. Remove and jumper the power backup switch
3. Remove and jumper the bypass switch

And you will rarely if ever have problems with it.

Mark

Posted by Chris Liczbinski (Member # 1957) on 04-06-2004, 03:33 PM:

Got the new backplane in this morning and the problem is the same as before. I tried 3 format cards (1 brand new- 2 known-good from other projectors, it didn't help anything. By looking at the schematics it is hard to understand what is happening- from the looks of it it has to be the backplane or format card.
Mark- thank you for the advice but we have a few new spare EQ cards that aren't working when they are put in and I even tried 2 from other projectors and they didn't work either so I eliminated the theory of it being the card. Yes, a real head scratcher!

Posted by Matt Zeiner (Member # 1914) on 04-06-2004, 03:41 PM:

Check the alignment of the plastic card guides to the backplane - I had a js 195 recently that had similar problems - turned out to be bad format card AND poor card alignment - poor contact...

Posted by Gordon McLeod (Member # 33) on 04-06-2004, 04:26 PM:

Swap the format with another processor remeber that the sub level and nonsynce are set on that card

Posted by Mark Gulbrandsen (Member # 72) on 04-06-2004, 05:13 PM:

Chris,

Absolutely swap the format card with another!! Be sure you remember which is which though as per Gords advice. Be sure the power is off when you yank it(literally!) from its edge connectors.
I would also reccomend that you call Clint at USL as well. He's a really good guy and USL is a very good company and will do what ever it takes to get your unit working again!!

Mark

Posted by Clint Koch (Member # 1179) on 04-06-2004, 05:24 PM:

Mark,

Thank you for the compliments. Chris and I have spoke yesterday and today. He has swapped out the format with another working one to no avail. The lead technician, JD Rios, will be in the theatre tommorow and I will touch base with both of them then. Thanks again for the kind words. Rest assured we will get this fixed.

Clint

Posted by Chris Liczbinski (Member # 1957) on 04-09-2004, 03:18 AM:

The sound problem was fixed today by our tech -JD Rios- who by the way is a great guy and very knowledgeable! It seems the problem was a combination of a bad motherboard backplane, bad format card and powersupply. I did not have all of these 3 things switched out at once, which must have led me to still have one problem or another. It just would have been nice to take care of the problem without calling a tech in! But now I do have just a hair more experience to draw upon!