Bipolar Power Supply Configuration

[Calaverasgrande]

Hi all, kinda new round here.
Searched for similar questions to mine and only found a few with a little bit of overlap, but not quite.

I'm trying to up my troubleshooting game so I've been filling out my bench tools.
One of these is a multi-out power supply.
Topward 6303D.
Up until this point I've only used fixed bipolar supplies. Such as a +/- 12v Tenma(or Velleman?) one I had. Or a +/- 44v one I built from a kit to power some old audio gear.
Now this Topward I am having trouble configuring to present the bipolar voltages I need.
My current audio projects are mostly 500 series modules AKA VPR alliance format.
Thats +/- 16v.
Great, so I connect up the Topward as indicated in the manual.
Put it in Series mode and connect to master and slave channels.
I'm getting +16V no problem from black and red terminals on the master channel.
However the diagram indicates I should get the -16V between the black terminals of the master and slave channels.
This isn't so.

Here is a kinda diagram of what Topwards telling me to do in series mode;
  O                 O
O O   O O   O  O
|_________||__|
-16V         0V    +16V


To my understanding I should be referencing both of these to a common ground.
So I'd assume connect the - of master and + of slave to ground ref. Then tap + of master and - of slave for those voltages. Right?
This is where I am stuck.
The power supply is supposed to switch all this internally, so I'm a bit worried about shorting something by configuring the bipolar outs this way.
I'm also curious if anyone else has experience with Topward PS. I got a deal on it, and it seems well built. But I'm still scratching my head.
Any insight would be much appreciated.
Apologies if this type of Q gets posted a lot. I couldn't find those if it is!

[rstofer]

Here is a kinda diagram of what Topwards telling me to do in series mode;
    O                O
  O O   O O   O  O
  |_||_______||_|
-16V           0V  +16V

I would think it would go like I revised your diagram.  The negative supply on the left has the -16V on the Black jack because the Red jack is connected to 0V.  The positive supply is just as you have shown it.

I would make the -16V RED to +16V Black with a 1k resistor just to see if it works.  Nothing in the manual says the output are floating or that this can be done.  A DMM should read the proper voltages without concern for the relatively low resistance.  OTOH, the 1k resistor is unlikely to short anything out.

https://www.topward.com.tw/data/6000.pdf

[Calaverasgrande]

Thanks,
Your version makes sense to me as well.
But this is what Topward says;




Just tested with the trusty old Micronta.
In the 'book' version I can't find -16v on any combination of terminals.
I'll dig out the resistors and give your configuration a go later on.
In the meantime I put it back into independent mode and verified that both channels work.
For a moment there I was doubting the 'slave' channel was functional.

[alsetalokin4017]

I have a Topward 6306D and it behaves like the OP's diagram and as the manual says. Check the slide switch position carefully and assure that they are in the Series position.

The Master channel is on the right, and in Series mode its voltage control controls both channels. So crank it to 16 volts and you should see the same on both voltmeters. Then stick your Negative DMM probe in the Master channel Grey jack and the Positive DMM probe in the Master Pink jack and you should read +16v. Keeping the DMM Negative probe where it is and  moving the DMM Positive probe to the Slave channel Grey, not Pink, jack and you should read -16V on the DMM.

For use as bipolar power supply the Master channel Grey jack is the circuit's common 0V reference.

(ETA: Make sure you haven't choked one channel down with the Current limiting! Turn both Current knobs past halfway up at least.)

[alsetalokin4017]

The slide switch config can be kind of confusing because both Series and Parallel modes have the Lefthand slide switch in the same position: to the right. The Righthand slide switch should be to the left for Series operation and to the right for Parallel operation.

[alsetalokin4017]

I am curious to know the results of
1) making sure the slide switches are correctly set for Series operation
2) making sure both channel Current knobs aren't turned down low
3) Setting Voltage with the Master (right hand) channel knob to 16 v, confirming both meters read the same
4) measuring output voltage by putting DMM negative probe in the Master channel Black (grey) jack and leaving it there
5) measuring Master channel Red (pink) jack with DMM positive probe and Slave channel Black (grey) jack with DMM positive probe

And 6) DMM positive probe in Master Red (pink) jack and DMM negative probe in Slave channel Black (grey) jack: should read +32 V.

ETA: Your trusty Micronta (Analog meter?)  reads negative voltages? Hmm..........

[alsetalokin4017]

Analog voltmeters, unless they are center-zero, only read in the positive direction I think.

So revised instructions for using Analog voltmeter with left-hand zero:

Assure slide switches correct, voltage set to 16V with Master V knob, both current knobs turned up.

Measure Master channel: Positive Micronta lead to Master Pink (red) jack and Negative Micronta lead to Master Grey (black) jack: should read +16V.
Measure Slave channel: Positive Micronta lead to MASTER Grey (black) jack and Negative Micronta lead to SLAVE Grey (Black) jack: should read +16V.
Measure Series voltage: Positive Micronta lead to Master Pink (red) jack and Negative Micronta lead to Slave Grey (black) jack: should read +32 V.

[Calaverasgrande]

Haha, it's a DMM not analog. But old enough that it has a lovely magenta/blue/avocado color scheme.

[alsetalokin4017]

OK good. Still curious... I don't think there is any difference in operation between the 6303 and the 6306...

I've got mine fired up right now, noisy fans and all, so if you want me to do any testing let me know please.

[Calaverasgrande]

OK good. Still curious... I don't think there is any difference in operation between the 6303 and the 6306...

I've got mine fired up right now, noisy fans and all, so if you want me to do any testing let me know please.

Ok so mine is normal to be that loud. I actually got replacement fans with my last Mouser order to fix that!
Anyway, looks like I misread the legend on the config switches, or moving them back and forth cleaned a contact.
1. Set both switches in the middle. In other words, left switch is to the right, right switch is to the left. 
2. Verified the current knobs are adequately turned up. When I zero them the channel will switch to CC. When I rotate past 10% or so it's back in CV.
3. Yeah, reads 16V on both. This has been the case. That's how I sleuthed the config switches. The other ways I had them V wasn't tracking. But it was in the original way I tried it?
4. Yeah 16V+
5. and yes 16V-!

Thanks for the help. Have to admit, the size and weight of the 6303D had me a bit intimidated. Worried it would melt if connected wrong.
Now on to actually troubleshooting my EQ and compressor module builds.

[alsetalokin4017]

Excellent! Glad to help.
Yes, you sure don't want to drop one of these Topwards on your foot. It would be fine, but your foot wouldn't...