DC POWER SUPPLY / General Science and Electronics / Forums

Forums

4hv.org :: Forums :: General Science and Electronics

« Previous topic | Next topic »

DC POWER SUPPLY

1 2 next

Move Thread

LAN_403

radioman

Fri Nov 18 2011, 02:59PM

Registered Member #3026 Joined: Fri Jul 23 2010, 02:46PM
Location: Los Angeles, California, U.S.A.
Posts: 54

Hi Everyone,

Is anyone familiar with the Instek DC power supply, GPS 3030D?? I purchased one at a flea market and it seems to be working but I have noticed an odd â€œhot spotâ€ on the top center under the plastic handle. This spot has apparently become so hot during operation that the paint is burned off and the plastic handle is partially melted! Taking off the cover, I see that there is a wire attached to the underside exactly under the hot spot. Is this a ground wire? And why does it get so hot?? Can anyone please explain??

Thanks a lot!

Platinum

Fri Nov 18 2011, 03:42PM

Registered Member #3926 Joined: Fri Jun 03 2011, 08:32PM
Location: UK.
Posts: 525

Maybe as it's used the thermal paste has decreased in efficiently, take it apart leave it run for a bit to see which part is very hot, and then you'd have to apply more thermal paste.

radioman

Fri Nov 18 2011, 04:38PM

Registered Member #3026 Joined: Fri Jul 23 2010, 02:46PM
Location: Los Angeles, California, U.S.A.
Posts: 54

THANK YOU, PLATINUM,

What do you mean by "thermal paste"? I don't know what this is. My power supply has a wire attached somehow to the inside of the metal case. This is where the heat is apparently coming from. I have used the supply for 20 minutes and it works fine. Can you tell me more?

Inducktion

Fri Nov 18 2011, 05:21PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

Thermal paste is stuff used to help transfer heat between two things... It fills in the microscopic cracks and gaps between the two metal surfaces.

Are you positive that's where the heat is being created? Are there any other components NEAR that spot, like, a transistor/heat-sink or large resistor? Those two things could very easily cause too much heat, and melt the plastic.

radioman

Fri Nov 18 2011, 06:18PM

Registered Member #3026 Joined: Fri Jul 23 2010, 02:46PM
Location: Los Angeles, California, U.S.A.
Posts: 54

The origin of the heat was exactly where a wire is connected to the inside of the metal case. (It seems to be "glued" in some way) It even burned the plastic handle opposite the wire on the outside. There are no components anywhere near this spot.
The strange thing is that when I test the unit for about 30 minutes, there is absolutely no warmth at this spot!

Inducktion

Fri Nov 18 2011, 07:09PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

Hm....Strange. It sounds like it might have been an external heat source, maybe a hot soldering iron, or something else along those lines.

As long as it works fine, I wouldn't worry too much about it!

Forty

Fri Nov 18 2011, 07:16PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

sounds like current might be flowing through the case at that spot. did you have the supply attached to a heavy load when you noticed the heating? If a ground wire somewhere else became detached, and the output ground terminal was electrically connected to the case, then the return current may of had to pass through the shell, and then into the wire where you noticed the heating. Does the insulation on the wire appear to be melted at all? (indicating that it was the wire heating up)

I guess if it works fine you could just slap a heatsink onto the hot spot and enjoy lol.

doctor electrons

Sat Nov 19 2011, 01:56PM

Registered Member #2390 Joined: Sat Sept 26 2009, 02:04PM
Location: Milwaukee Wisconsin
Posts: 381

The connection may be heating up because it has lost some of its connection. If that point has been
heating up and cooling down repeatedly for a long time the electrical connection may have suffered.
I would remove it, clean everything up, and reconnect it making sure it is electrically sound.

I have seen in some older power supplies a blob of sealant or glue over soldered ground points.
If you know for sure it is a ground connection simply replace it, maybe even use a heavier awg
wire to better handle current without getting so hot.

radioman

Sat Nov 19 2011, 02:17PM

Registered Member #3026 Joined: Fri Jul 23 2010, 02:46PM
Location: Los Angeles, California, U.S.A.
Posts: 54

Thank you Doctor Electronics!

Yes, it is a groung connection and it looks like it was sealed in a blob of something which also shows signs of burnung. I will replace it. Thanks for the good info!

Patrick

Sat Nov 19 2011, 05:13PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

I agreee with doctor electrons, but maybe you should post pics before and after you mod it.

when people have questions, their pics ar often more useful to us then their words.

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob