OSA Rack Debacle.....

[darnell]

Hey all. 

Wondering if anyone can help me out. 

I have an OSA 8 space rack with the dual power supply.  Apparently, the 48v went on it, and was rewired by another person with another 48V power transformer (apparently from a doorbell?!?!).  It again stopped functioning properly and now I am trying to get it up and running so I can use it.  Not sure what the original configuration was, but I am getting this for voltages from the 4 pin connector to the actual lunchbox.

Pin 1 - 50V
Pin 2- 34V
Pin 3- 18V
Pin 4- 10V

I have a 48v power one PS if that helps. 

Not sure what's going on in the power supply, but those voltages seem a little weird.  If anyone has this power supply, some pics as to how it was stock would be helpful.  Ill post pics of this one with the "doorbell" PT in a minute.

Anyway,  any help would be greatly appreciated. 

Daryl

 

[darnell]

Here's some pics.  Lemme know if you need more. 

The Power One 48v supply I have is model HC48 1.0

http://s92.photobucket.com/albums/l19/strangewaysrecording/OSA%20Power%20Supply/

Daryl

 

[abechap024]

I don't have experience with this box...but those voltages are definitely non conforming! It looks like the voltages should be regulated coming out of the box.

Is the equipment that the power supply feeds opamp based? if so you probably the 4 rails need to be:

+15v to 18v
-15v to 18v
0 or ground
and the +48v

What are you referencing as "ground" when you measure that voltage? That could maybe be why the voltages seem so screwy when you measured them.

Good Luck!

 

[darnell]

If you look in the pics, it's the second power one with the yellow jumper clipped to it. I checked continuity to ground.  Should I be referencing from elsewhere?

 

[abechap024]

Well it depends on how the power supply is set up. If the "power" ground and the "chassis" ground are the same then it isn't a problem. But sometimes manufactures keep power and chassis separate, in that case if you tried measuring between each of the 4 pins referencing one as ground until you found some readings that made sense, then you might be in luck...

But if thats not the case, then looks like your power supply is fried. What are some of the chips it uses?

looked at the pics again and looks like there are two 15v  regulator modules one for positive one for negative.

 

[Harpo]

Get your safety ground between IEC inlet and your metal box hooked up with a short permanent safe wire connection !
You measure your DC voltages with reference connected to 0V.
No need to also link your 0V from the +15V/0V/-15V supply to your case ground, if the +48V phantom has its own reference that connects to your case ground/XLR-pin1/EDAC-pin1 card edge connector for phantom return current.

 

[Sarcastic Sound]

contact Atlas Pro Audio, they handle all the OSA repairs for Dale. They can point you in the right direction or even fix it for you.

 

[darnell]

I sent an email to Atlas.  I'll keep updating, since I'm sure I'm not the only one whose had a PS problem.    ;D

Thanks for the help.

Daryl

 

[mitsos]

Don't bother with atlas.

http://www.atlasproaudio.com/osa2.html

We no longer carry OSA Products.
For sales, questions, warranty repair or other issues, please contact the CEO of OSA directly.
Dale Epperson's email is haremoor @ yahoo.com
OSA's Phone Number is 717-571-0515.

btw, have you tried measuring at the edge connector? While each mfg can vary which pin of a power connector carries what voltage, on the rack power is at the bottom four pins.
pin 12: +16V
Pin 13:  0V
Pin 14: -16V
Pin 15:  +48V (bottom pin)

Use pin 13 as your 0V reference.

 

[darnell]

btw, have you tried measuring at the edge connector? While each mfg can vary which pin of a power connector carries what voltage, on the rack power is at the bottom four pins.
pin 12: +16V
Pin 13:  0V
Pin 14: -16V
Pin 15:  +48V (bottom pin)

Use pin 13 as your 0V reference.

Tried this and got correct voltages.  The phantom is at 45v.  45v should be enough for most condensers, no? 

Not sure why it is cutting out, unless the transformer has an issue. 

Still waiting to hear back from OSA.  Hopefully they will shed some light on this and I can get the Power One installed.

d.