Film-Tech Forum ARCHIVE: Fixing an Ultra Stereo power supply

This is topic Fixing an Ultra Stereo power supply in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Chris Hipp (Member # 1788) on 01-02-2004, 12:14 AM:

I knwo these have been discussed a lot on here, but my engineer told me that I can connect or "jumper" four of the prongs on either the bypass or the power switch. The problem is that I cannot remember which one he said and he is on vacation for another week.

Anyone know which switch it is?

Posted by Gordon McLeod (Member # 33) on 01-02-2004, 12:27 AM:

First which model of processor and powersupply
2 what has failed on it
then we can possibly tell you how to fix it
If it the JS serries replacements can be ordered

Posted by Chris Hipp (Member # 1788) on 01-02-2004, 12:50 AM:

Sorry, it's a JPS 10d

The middle LED does not light up, I think it is the +15v.

The -15v LED does light up.

Other than that im not sure. I was told that putting the jumpers on the switch would probably fix it.

Normally I would jsut send it back but USL is closed until the 3rd and it will take another couple days for them to send it (maybe longer if they are backed up from the holidays). So I would like to try to fix it so it isnt down for another week.

Posted by Gordon McLeod (Member # 33) on 01-02-2004, 06:53 AM:

Also check the voltage regulator
unless someone has been using the bypass switch on the powersupply that probably isn't the problem

Posted by Matt Zeiner (Member # 1914) on 01-02-2004, 08:39 AM:

sounds like the reg to me, but those pesky switches on those things do have a habit of screwing (read - burning) up. Does your power supply module have an "ext. power" switch on it or is there just a hole with a plug there? That is the one to jumper if you have it - I can't remember if it must be jumped N.O. or N.C, but try out both - nothing will get hurt any further.

The ext. power switch on those things seems to like to burn up (smoke!) even if it has NEVER been used, Gordon.

Posted by Mark Gulbrandsen (Member # 72) on 01-02-2004, 10:00 AM:

It might be the regulator but it far more likely to he the Ext. power switch if there is one on your unit. That dam external power switch ALWAYS fails sooner or later all by itself with out ever being used. It simply cannot take the current it is passing over a long number of years. I'd rate this USL problem up there with the exploding caps problem they had a number of years back. I've got to wonder how many cinemas drivers this has also taken out in various theatres...... Loosing either voltage rail through that switch causes a NASTY high power pulse to hit the B chain.

I remove everyone of these I come across and jumper the positions holes. I removed ten of them just on my last service trip! Even USL no longer installs them on new supplies.

To jumper it out remove the switch by clipping it to shreds with a small set of pointy wire clippers, or of you can get under the switch with a small pointy pair of clippers then simply clip the switch out. Then heat up the solder pads and pull whats remaining of the pins out of the pads, Then install at least a 16 ga jumper wire them from each of the the center pads to the front pads which are the ones closest to the front of the PCB. Do both top and bottom sets of pads. One set of solder pads is for +15 volts and the other is for -15 volts.

There are alot of screws to remove to get the board freed from the metalwork, but this shouldn't take even an inexperienced person more then an hour to complete. Its very easy and be sure to do this to all the units in your plex!!

Mark

Posted by Steve Guttag (Member # 268) on 01-02-2004, 10:47 AM:

I'm wagering on the External Power pushbutton too. Along with the EQ card relay, it is my #1 cause for USL JS processors to "go down."

I think I was ahead of the curve when it came to getting rid of these suckers. The units I modified all have 3M Bumpons (same as the Neumade splicer feet) covering the hole. They tend to stick over the hole better than to the bottom of the splicer too.

Steve

Posted by Chris Hipp (Member # 1788) on 01-02-2004, 11:44 AM:

Thanks Guys!

I am assuming that External power is the same as the bypass button. they do have the AC adapter back up plugged in.

Posted by Mark Gulbrandsen (Member # 72) on 01-02-2004, 11:55 AM:

Chris,

The switch we're referring to is in the upper right hand corner of the face of the power supply. The bypass switch is normally located on the format module in the center of the processor.

Mark

Posted by Chris Hipp (Member # 1788) on 01-02-2004, 09:42 PM:

Yes, I was referring to that same switch, I get the "standby" and "bypass" confused. IT is the Standby on the power supply. I fixed two of them today.