Maxent MX-42HPM20 Won't turn on

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  • PlainBill
    Badcaps Legend
    • Feb 2009
    • 7034
    • USA

    #21
    Re: Maxent MX-42HPM20 Won't turn on

    Originally posted by el3ctroded
    Nope, not a bad inverter.

    I'm really stumped. So I dragged out the scope. There's a bit of noise (800-900mV) on the 5V outputs, and about the same on all other outputs.

    All other voltage rails are to spec. Getting clean 185V, 58V, 24V, 12V.

    So do you think that's too much noise on the 5V rail? There's a filter on the main logic board that drops noise down to about 500-600mV, but that still seems high to me. What do you think?
    That definitely sounds like too much noise.

    PlainBill
    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

    Comment

    • el3ctroded
      Senior Member
      • Nov 2008
      • 198
      • USA

      #22
      Re: Maxent MX-42HPM20 Won't turn on

      Well, took the diode on the +5v rail out cause it seemed like it was testing odd. It passes diode check, but fails resistance check. Both directions conduct. Dual diode, common K Part B-2306 Schottky

      Took out a cap after the diode, no problems there. Maybe it will work if I replace the diode.
      Last edited by el3ctroded; 06-09-2010, 06:51 PM.

      Comment

      • el3ctroded
        Senior Member
        • Nov 2008
        • 198
        • USA

        #23
        Re: Maxent MX-42HPM20 Won't turn on

        Strange. There's no regulator IC after the transformer and diode, just a filter formed by an inductor and bunch of caps.

        Thought I might have had a diode in the parts boxes... no such luck. Guess I have to wait on Mouser.

        Comment

        • el3ctroded
          Senior Member
          • Nov 2008
          • 198
          • USA

          #24
          Re: Maxent MX-42HPM20 Won't turn on

          Well, I thought: The hell with it. A good PSU is only $100 on ebay. So I bought it. Same damn problem! PSU doesn't kick on unless the switch is in auto mode, where it shouldn't be.

          ARGGG! So where am I at now? Logic board fault?

          Comment

          • el3ctroded
            Senior Member
            • Nov 2008
            • 198
            • USA

            #25
            Re: Maxent MX-42HPM20 Won't turn on

            Nope, missed a connector! Screen is working properly!

            $220 for a fixed screen. I noticed the Ysus board gets really hot, so I've added an exhaust fan above it. Hopefully it will last longer with the extra cooling.

            So I also got a 42" Poloroid LCD for myself that didn't work. Fixed it too with a new PSU! Got myself a new TV LOL. I'm on a roll!

            Comment

            • crtfool
              Senior Member
              • Jun 2010
              • 82
              • USA

              #26
              Re: Maxent MX-42HPM20 Won't turn on

              Glad you got it working! Nice score on the Polaroid too - what was you final cost investment to get it working?

              I had a bit of luck too today - just ordered an allegedly working power supply for my Plasma for a total cost of $61. I'll keep you posted when I receive it.

              Comment

              • crtfool
                Senior Member
                • Jun 2010
                • 82
                • USA

                #27
                Re: Maxent MX-42HPM20 Won't turn on

                Well - the jerk on eBay refunded my money for the power supply saying that it is "no longer available". I checked his feedback and found out that he has done this to other buyers in the past.

                Comment

                • retiredcaps
                  Badcaps Legend
                  • Apr 2010
                  • 9271

                  #28
                  Re: Maxent MX-42HPM20 Won't turn on

                  I have had that happen to me a couple of times. A bidder puts a $100 item on ebay for 99 cents starting price, but only attracts one bid (mine) and then claims item is no longer available.

                  Of course, I watch this seller and sure enough 2 weeks later the exact same item comes up for bid BUT with a reserve price.

                  I have lucked out on many items (high value) where I'm the only bid and I get it for 99 cents.

                  Originally posted by crtfool
                  Well - the jerk on eBay refunded my money for the power supply saying that it is "no longer available". I checked his feedback and found out that he has done this to other buyers in the past.
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                  Comment

                  • crtfool
                    Senior Member
                    • Jun 2010
                    • 82
                    • USA

                    #29
                    Re: Maxent MX-42HPM20 Won't turn on

                    Originally posted by retiredcaps
                    I have had that happen to me a couple of times. A bidder puts a $100 item on ebay for 99 cents starting price, but only attracts one bid (mine) and then claims item is no longer available.

                    Of course, I watch this seller and sure enough 2 weeks later the exact same item comes up for bid BUT with a reserve price.

                    I have lucked out on many items (high value) where I'm the only bid and I get it for 99 cents.

                    The power supply was just listed today - 30 day listing - $49 buy it now or best offer plus $12 shipping. I grabbed it for the $49 - did not want to have someone grab it out from under me, so I gave him his price and paid immediately. It's not like he canceled all the bids and ended the auction - i have had that happen too - he pulled this stunt with a completed auction. He must have realized that it was worth more, and pulled the old "no longer available" game - I do not believe him because it was a new listing - it might be a valid point if the listing was old. I am going to watch to see if he re-lists it.

                    I also have had people do this on Craigslist - we make a deal for their asking price, then they call me and say that they got a higher offer - I tell them that this is not eBay, and I am not going to start bidding on their item.

                    Comment

                    • el3ctroded
                      Senior Member
                      • Nov 2008
                      • 198
                      • USA

                      #30
                      Re: Maxent MX-42HPM20 Won't turn on

                      LOL @ crtfool and the craigslist thing... That's pretty good.

                      I got the Poloroid and it's PSU for a total of $160!

                      Just picked up a Dynex 32" LCD today for $16! I had to drive 4hrs round trip to pick it up (about $30 in gas), but once home I had it fixed within 10 minutes! It had a bad solder joint on PSU that caused an SMT diode to fry and I had a new one in the parts cabinet that was "close enough" till I make another Mouser order. Got a nice bedroom screen now

                      Comment

                      • Noob tube
                        New Member
                        • Oct 2013
                        • 1
                        • Usa

                        #31
                        Re: Maxent MX-42HPM20 Won't turn on

                        Sounds like you have experience with a problem I am having with my Maxent. I have sound but no picture, may I ask your advice?

                        Comment

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