I have a Behringer UB2442FX Eurorack mixer. Before the flames start,
I liked it, when it was working. It did exactly what I needed.

It died, out of warranty, and the switching power supply looks to be
toasty. Behringer US doesn't have PS modules yet, so it looks like
board level repair is where it's at.

It uses very close to a demo circuit from Power Integrations from
their TOP245Y chip. However, I don't know what the final voltages are
other than there should be a +5V (Based on the 7805 regulator) and
there should be a 48V. There are 5 voltages available, guessing from
the connector.

ANyone help out with at least the voltages coming out of this
doohickey would be appreciated. Any other help would also be
appreciated.

Thanks

Jake Joseph

In article ,
Jake Joseph wrote:
I have a Behringer UB2442FX Eurorack mixer. Before the flames start,
I liked it, when it was working. It did exactly what I needed.

It died, out of warranty, and the switching power supply looks to be
toasty. Behringer US doesn't have PS modules yet, so it looks like
board level repair is where it's at.

It uses very close to a demo circuit from Power Integrations from
their TOP245Y chip. However, I don't know what the final voltages are
other than there should be a +5V (Based on the 7805 regulator) and
there should be a 48V. There are 5 voltages available, guessing from
the connector.

I'd guess a +15V and a -15V. Maybe a little higher, but probably not
much higher than that.

If it's a switching supply, my guess is that the regulation is probably
done using the 5V line as a reference. If it were done properly, they'd
be using the difference between the +15V and -15V rails as as reference,
though.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Almost always +/-15VDC. What are the rated voltages on the caps?
Most of that Chinese stuff uses 16V caps on the rails.

LV




Jake Joseph wrote:

I have a Behringer UB2442FX Eurorack mixer. Before the flames start,
I liked it, when it was working. It did exactly what I needed.

It died, out of warranty, and the switching power supply looks to be
toasty. Behringer US doesn't have PS modules yet, so it looks like
board level repair is where it's at.

It uses very close to a demo circuit from Power Integrations from
their TOP245Y chip. However, I don't know what the final voltages are
other than there should be a +5V (Based on the 7805 regulator) and
there should be a 48V. There are 5 voltages available, guessing from
the connector.

ANyone help out with at least the voltages coming out of this
doohickey would be appreciated. Any other help would also be
appreciated.

Thanks

Jake Joseph

(Scott Dorsey) wrote in message ...
In article ,
Jake Joseph wrote:
I have a Behringer UB2442FX Eurorack mixer. Before the flames start,
I liked it, when it was working. It did exactly what I needed.

It died, out of warranty, and the switching power supply looks to be
toasty. Behringer US doesn't have PS modules yet, so it looks like
board level repair is where it's at.

It uses very close to a demo circuit from Power Integrations from
their TOP245Y chip. However, I don't know what the final voltages are
other than there should be a +5V (Based on the 7805 regulator) and
there should be a 48V. There are 5 voltages available, guessing from
the connector.

I'd guess a +15V and a -15V. Maybe a little higher, but probably not
much higher than that.

If it's a switching supply, my guess is that the regulation is probably
done using the 5V line as a reference. If it were done properly, they'd
be using the difference between the +15V and -15V rails as as reference,
though.
--scott


Well, you are right about the 5V - it gets its reference off of the 5V
- shoots this through a TL431 regulator.

I'm guessing that either the switcher has gone bad or the optoisolator
xsistor has gone bad...any good way to diagnose?

Jake

(Jake Joseph) wrote in message . com...
I have a Behringer UB2442FX Eurorack mixer. Before the flames start,
I liked it, when it was working. It did exactly what I needed.

It died, out of warranty, and the switching power supply looks to be
toasty. Behringer US doesn't have PS modules yet, so it looks like
board level repair is where it's at.

It uses very close to a demo circuit from Power Integrations from
their TOP245Y chip. However, I don't know what the final voltages are
other than there should be a +5V (Based on the 7805 regulator) and
there should be a 48V. There are 5 voltages available, guessing from
the connector.

ANyone help out with at least the voltages coming out of this
doohickey would be appreciated. Any other help would also be
appreciated.

Thanks

Jake Joseph



Simple, quick, common fix; one of the secondary rectifiers is shorted
(usually Ref #D6), be sure to replace with a 'fast' rectifier (we use
# HER508).

Cheers,
-Robert
QTS
http://www.Braught.com
(Authorized BEHRINGER Service)
Real Email Addy : (Remove NoSpam to Reply :
Duh!)

Jake Joseph wrote:

Well, you are right about the 5V - it gets its reference off of the 5V
- shoots this through a TL431 regulator.

I'm guessing that either the switcher has gone bad or the optoisolator
xsistor has gone bad...any good way to diagnose?

Diode tester function on a multimeter will help you check the switching
transistor in-circuit. You can do the same with the optoisolator. You
can't find all possible failures in-circuit but you can find some of them.
Worst case you pull it out, test the switching transtor with the Hfe function
on your multimeter and swap out the optoisolator (being sure to put a socket
on the optoisolator because this will happen again someday).

Switching supplies are no fun to fix, because you can't get them running
to do diagnosis. A storage scope can help a lot.

Don't forget the kickstart circuit either, which is a source of failure in
a lot of switching supplies.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

(Robert M. Braught) wrote in message . com...
(Jake Joseph) wrote in message . com...
I have a Behringer UB2442FX Eurorack mixer. Before the flames start,
I liked it, when it was working. It did exactly what I needed.

It died, out of warranty, and the switching power supply looks to be
toasty. Behringer US doesn't have PS modules yet, so it looks like
board level repair is where it's at.

It uses very close to a demo circuit from Power Integrations from
their TOP245Y chip. However, I don't know what the final voltages are
other than there should be a +5V (Based on the 7805 regulator) and
there should be a 48V. There are 5 voltages available, guessing from
the connector.

ANyone help out with at least the voltages coming out of this
doohickey would be appreciated. Any other help would also be
appreciated.

Thanks

Jake Joseph



Simple, quick, common fix; one of the secondary rectifiers is shorted
(usually Ref #D6), be sure to replace with a 'fast' rectifier (we use
# HER508).

Cheers,
-Robert
QTS
http://www.Braught.com
(Authorized BEHRINGER Service)
Real Email Addy : (Remove NoSpam to Reply :
Duh!)

Thanks to all that helped! I think the secondary diode is bad. Scott
is right, these sure are not fun to diagnose - I'm used to tube amp
PS's which are a whole lot easier....

The fast diode is to cope with the frequency of the switcher - right?