Instek GPS2303

[BloodyCactus]

So.. finally bit the bullet and got myself a nice bench power supply. I had seen pics on here of someones Instek 4303, but since I didn't need the quad outputs I went with the base double output model 2303, hoping that the inside was much the same, and it was! I got it from Test Equipment Depot via Amazon since I had a bunch of reward points stacked up I only paid $100 for it which was a nice way to maximise my budget.

Its got a nice toroidal transformer, the knobs turn as smooth as a babys bum.

Not having a real power supply before I didn't quite realise how it worked. If you turn the amps to zero, the DMM will register the voltage but the PSU display shows 0. If you adjust the amps, you'll get a reading to match. Also without a load, the amps display stays at 0, so I stuck the jack into the DMM 10A slot and voila! Amps registered on the PSU.

So once I had my amps dialed in, I yoinked that, and put it back in for volts and dialed in 5v. Since the knobs are so smooth you have to hunt to get say, exactly 5, otherwise a bees dick will shunt it from 4.8 to 5.1 etc.

If your output switch is off, the display will be 0.

All readings on the display matched on my DMM. The PSU even came with a calibration printout from the factory, I dont know if this is standard or not, I did notice no calibration sticker on the unit so, I will take that calibration paper for what its worth, 0$.

The inside looks much like the photos from Cybergibbons Instek GPS4303 with some slight differences.

front view


internals from the side


the tallboy


outside fuses are glued down, the two in the middle are not.. odd..


hmm a Dynamic Load jumper config for the right side (ch1)


the left side (ch2) has.. a bunch of pots and the same dynamic load jumper


on top of the heatisnks...


you can see the tallboy is glued down and the pcb is labled PS11P02A



larger versions of the images;

[olsenn]

I have the 4 channel version (GPS-4303) and I love it too.  I admit I never use the two non current limited outputs, but they're nice to have in case you need to power some IC's on a seperate rail and don't feel like making a potential divider or virtual ground.

Let it be said that no self designed PSU following the design videos on eevblog will match the performacne of one of these sub $400 professional PSU's; they provide great educational value, but that is all.

[cybergibbons]

Sounds like it behaves a bit differently to mine.

On the GPS-4303, when the output is off, the voltmeter and ammeter will show the approximate output voltage and current limit. I find the voltage is very close, but the current limit readout is high. When you turn the output on, the voltmeter reads actual volts and the ammeter the actual amps. I always set the current limit by shorting the output.

If you have the current limit turned to 0, then you get no voltage out. There is a fairly wide dead band on the current limit potentiometer for 0 current.

After a few years with this power supply, I still like it. Some have complained about the channel ordering being odd and the ammeter and voltmeter being the wrong way round. I haven't found this to be an issue. I don't like the single output on/off button - I'd like to be able to control each channel.

[BloodyCactus]

yep, the not showing display when output is off is specific only to the 2303, the other x303 models show it. odd, but I found it in the manual.

as for the channels back to front.. it makes no difference to me, function over fashion. but I would loved to have an output switch for each channel, considering most low end PSU dont even have an output on/off button, I'm happy.

At some point, I'm going to play with the dynamic load jumper and see what it does.. maybe.

[FenderBender]

What the whole Master/Slave thing mean?

[BloodyCactus]

the master slave  channel 2 can be slave to channel 1. so if you do series or parallel, you can tell ch2 to be exactly the same A/V as channel 1, or you can add channel 2 output to channel 1 to get a full 60V/6A.

[Tube_Dude]

...or you can add channel 2 output to channel 1 to get a full 60V/6A.

Hi

In this last case you can get 60V/3A, because current don't add. 

[cybergibbons]

The dynamic load jumper loosens the current limit for use with audio amps so that it stays in CV rather than CS mode.