Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: Cornholio on March 11, 2011, 03:54:06 PM

Title: Bench power supply questions. Am I reading the voltages properly?
Post by: Cornholio on March 11, 2011, 03:54:06 PM
I just picked up this Micron Dinergy power supply so I could start experimenting.  The secondary connectors are across the top as seen in the picture.  I'll label them as the following :  Ground plus1 plus2 minus1 minus2 (from left to right).

I hooked up the primary wire inputs(towards bottom of picture) to a standard US power cord as follows :  

L    connected to black
N    connected to white
GND  connected to green

I'm getting voltage readings I don't understand:

If I put black probe on ground and red probe on minus1 or minus2 I get -24 volts DC which is what I expected.

If I put black probe on ground and red probe on plus1 or plus2 I get 62 milivolts DC.  I was expecting +24 DC.

Any combination of minus to plus yields a + or - 24 volt reading.  Is the power supply functioning properly?

Any help greatly appreciated.

Title: Re: Bench power supply questions. Am I reading the voltages properly?
Post by: awdman on March 11, 2011, 09:02:25 PM
it looks to me that that is not a negative/postive power supply, just a positve rail.  hook your black to - and red to + and tell me if you get +24vdc.
Title: Re: Bench power supply questions. Am I reading the voltages properly?
Post by: polo16mi on March 11, 2011, 09:21:21 PM
I found Micron site at http://micronpower.com/products/selection_guide.php (http://micronpower.com/products/selection_guide.php)

Maybe you can find your model on that table and identify properly how much tension you can expect at terminals.

The picture posted looks like MD120-24-1 model.   Datasheet says that it has an adjustable output of 22-28 V

Here datasheet http://micronpower.com/pdf/MD120-spec.pdf (http://micronpower.com/pdf/MD120-spec.pdf)

Hope help.
Title: Re: Bench power supply questions. Am I reading the voltages properly?
Post by: Cornholio on March 12, 2011, 01:28:48 AM
Quote from: awdman on March 11, 2011, 09:02:25 PM
it looks to me that that is not a negative/postive power supply, just a positve rail.  hook your black to - and red to + and tell me if you get +24vdc.

Yes,  +24 vdc
Title: Re: Bench power supply questions. Am I reading the voltages properly?
Post by: Cornholio on March 12, 2011, 01:32:52 AM
Quote from: polo16mi on March 11, 2011, 09:21:21 PM
I found Micron site at http://micronpower.com/products/selection_guide.php (http://micronpower.com/products/selection_guide.php)

Maybe you can find your model on that table and identify properly how much tension you can expect at terminals.

The picture posted looks like MD120-24-1 model.   Datasheet says that it has an adjustable output of 22-28 V

Here datasheet http://micronpower.com/pdf/MD120-spec.pdf (http://micronpower.com/pdf/MD120-spec.pdf)

Hope help.

I bought this to power an lm3886t chipamp.  You are correct.  It is MD120-24-1.  I guess it isn't going to work because it's not a "bipolar"  power supply.  Is that the right terminology?

What do you mean by tension?

Am I correct in assuming the upper far left connector is ground?
Title: Re: Bench power supply questions. Am I reading the voltages properly?
Post by: J M Fahey on March 12, 2011, 02:07:25 AM
"Tension" means "Voltage"
Well, you can buy *another* PSU and use both (in series) to power your LM3886. ;)
Title: Re: Bench power supply questions. Am I reading the voltages properly?
Post by: polo16mi on March 12, 2011, 11:37:48 PM
Quote
Am I correct in assuming the upper far left connector is ground?

In first page of datasheet, at fifth feature, you can see that it has a "DC OK LED Indicator w/remote indicator contact". I am not 100% sure, but i bet that this"far left connector" is for use to connect for example to a PLC or SCADA system, for "power fail" indication. May be it is a relay output that change of state if power supply shut off. For check it, you can set up you tester for measuring Voltage DC, connect red probe at "far left connector" and black probe at any (-) or ground terminal, at far lower right. You will read something.. donĀ“t know what, but i guess probably something around 5V. Next, without changing the probes setup, unplug of AC your power supply. Keep reading tester display and it should be change to 0V.
If something like that occur, this "far left connector" is NOT GROUND 100% sure.