Tekpower TP1803D Variable Power Supply, no power

[arcfault]

I have a Tekpower TP1803D that I got off Ebay. I was able to get a refund on it because it's not putting out any power. Pretty odd.

Turns on fine. If I put a voltage on it, it reads the voltage on the display. Seems to cycle from constant voltage to constant current as one might expect when messing with the voltage and current knobs.

Nothing funny looking, smelling, etc, after taking the case off.

Would appreciate some advice on where to start.

Thank you!

[Shonky]

Looks super cheap and nasty - careful with mains inside.

The back board on the heatsink looks to be the actual supply so I'd be looking at whichever lines are the input from the transformer. Check for AC around 20-25V. Then should be a rectifier and the big filter cap. Check for DC there (and also AC).

With it off it may be worth checking the windings for continuity. It seems the front board is working - possibly running off a separate winding to the supply board. That also rules out the mains side primary winding.

[arcfault]

I was thinking as well that there must be an extra winding just to power the basic circuitry. That's a great place to look, thank you!

If I can't get this one going, what would be a more reputable linear power supply? I've been wanting to test for ripple in solar charge controllers, but if I'm starting with ripple (I also have a switching power supply) I think I won't have reliable results.

[u666sa]

Well wait a minute. Just because it's crap, doesn't mean it has the right to exist. My yaxun made me a ton of money back in 2014. Back then there was flip phones, nokias, and very few iphones. It is still useful. I still use it to charge stuff.

First thing you do is check that transformer gives you power.

Then you check all the caps -- desolder and check ESR... You should have ESR meter. Here is a link to one -- click -- trust me, it's a money maker! If no ESR meter, replace all caps, but beware, new comes sometimes are bad.

Then, if that don't help. We'll look and see further.