Actions
Forum Thread Details
  • State Suggested Answer
  • Replies 120 replies
  • Answers 51 answers
  • Subscribers 289 subscribers
  • Views 9220 views
  • Users 0 members are here
Related

Need to get MG Electronics Power Supply repaired...or NOT!?

Former Member

Hi.

I just bought a lot of Slot Car stuff, yes those cars that go around a track. The guy was serious about his hobby he didn't have the usual wall plug in power pack, he used a MG Electronics PS-10AD, 0-20 VDC at 10 Amps. Well this power supply doesn't work anymore. It does turn on and the red overload light stays on. It doesn't put out anything. I used my multimeter etc., nothing. I know that these are made overseas . They did retail for about $200. So the questions is were can I get it repaired OR should I ? I'm in Western MAss.

I did check the fuse , it's fine. I've got a heavy door stop on my hands, it does have a nice handle and cord on it !

Many thanks for info, Ted

 

http://www.mgelectronics.com/shopexd.asp?id=179

Parents
  • 0

    I gotta make some guesses since we don't have the schematic at hand.  If I'm wrong, it doesn't mean I am a dummy, it just means I'm wrong.  Now, if you would just explain this to my wife. . .

     

    Okay, this thing is really made of discretes.  It is an oldie, but nice and well worth fixing.  This is good, everything is explicit.  The two chips are 741 op-amps, the same chip that governed the Love Controls at my first job.  Take heart.  Notice that the bridge rectifiers are made of discretes.  There is one wire there, that when soldered caused the insulation to bulge from excessive heat.  It will work fine, but it shouldn't have passed Q/A.

     

    I think one 741 is acting as a feedback controller for the supply and the other is a comparator for the overload function.

     

    Going for a quick kill, see if you can pull the covers off the power transistors on the back of the unit and find the part numbers for them.  If they are bipolars, they will be fairly easy to test, if they are Darlingtons it will be a wee bit tougher.

  • 0 in reply to D_Hersey

    I attempted to take the covers off the back 2 power transistors. Those caps are held on by a lock nut and nut on the opposite blind side. I can't get them off. I had one set of nut and washer fall off that's how I know about connectivity. I haven't ventured into taking off the giant heat sinks in back. I can see the screws. I don't know how things are connected. Are the power transistors just pushed into place and not soldered ? If I attempt to take off the heat sinks will the power transistors come with it and there will be a wires connecting everything together ? I just don't know.

    Anyhow...thanks !

    Ted

Reply
  • 0 in reply to D_Hersey

    I attempted to take the covers off the back 2 power transistors. Those caps are held on by a lock nut and nut on the opposite blind side. I can't get them off. I had one set of nut and washer fall off that's how I know about connectivity. I haven't ventured into taking off the giant heat sinks in back. I can see the screws. I don't know how things are connected. Are the power transistors just pushed into place and not soldered ? If I attempt to take off the heat sinks will the power transistors come with it and there will be a wires connecting everything together ? I just don't know.

    Anyhow...thanks !

    Ted

Children
No Data