Bought power supply, only half works.

Discussion in 'The Projects Forum' started by GRNDPNDR, Mar 7, 2014.

  1. GRNDPNDR

    Thread Starter Member

    Mar 1, 2012
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    With the cost of shipping the unit, and the additional $100 in brokerage fees, I basically cannot afford to send it back for replacement to pay another $200 in total brokerage fees as well as shipping both ways..... I might as well just buy TWO more power supplies.

    So my only option might be to try and diagnose and fix it myself if possible, which is why I've come here because I don't know where to start looking at it.

    It's a Mastech (RSR) HY3005F3, and the master channel doesn't seem to output any voltage.

    the slave channel works fine, as well as the 5V constant so it could be a problem with one of the boards inside?

    I was going to swap the boards but they soldered a couple of connections on and it makes it difficult to move without serious work.

    I didn't notice anything wrong with the boards or any components physically, or at least nothing stood out.

    so aside from that, is there anywhere I should start looking or checking to find the source of the problem?
     
  2. Veracohr

    Well-Known Member

    Jan 3, 2011
    552
    76
    If you bought it new and it didn't work out of the box, shouldn't the seller be responsible for the replacement shipping costs?
     
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,771
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    could be absolutely anything.. open it up..look..take pics..
    could be as simple as a broken/bad wire/connection..
    new/used?

    and damn..where do you live that you have all those fees..? its only $200 new
     
  4. GRNDPNDR

    Thread Starter Member

    Mar 1, 2012
    435
    7
    Canada, purchased new through Amazon. The seller will offer a refund, but heres th problem

    it cost me $231 with shipping cost. In Canadian dollars that turned out to be $263.

    Add on to that UPS $94 brokerage fees, I've now paid $357 CAD to buy this unit.

    Now if the seller refunds me $231 USD, I recieve only $251 CAD in return (today), Plus they also don't refund the $94 brokerage fees, so then I'm out about $105.

    All this just to return the unit for a "refund" where I lose money.


    I have looked inside the unit without tearing it completely apart at this time, and nothing stood out. I checked the connectors, checked the traces but the end result is the same so far,I adjust the pot and get no output through the master channel. it will switch into CC/CV mode.
     
    Last edited: Mar 7, 2014
  5. Experimentonomen

    Member

    Feb 16, 2011
    331
    46
    It sounds like the regulation circuitry prior to the pass transistor is not doing its job, or the pass transistor itself is faulty.

    Easiest route is to find the schematic for the unit and start measuring voltages, seeing if they are within spec.
     
  6. GRNDPNDR

    Thread Starter Member

    Mar 1, 2012
    435
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    I'll look around and see if I can find a schematic....that could take a while though.

    of note is the fact that when I adjust the voltage knob, there is no clicking of relay's as there is with the slave channel.

    However, the slave channel relays click at about 4V, and since I don't even get any output on the master channel I can assume that something is not getting to the "supply board" for the master channel.

    where this becomes a problem is that I have to practically take apart the entire unit just to get to the smaller boards on the front panel.

    I'll try and get some pics/video up later.
     
    Last edited: Mar 7, 2014
  7. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
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    Have you see the line voltage selector to the correct setting?

    Maybe you could post some pictures of the boards inside...
     
  8. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
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    Being new, all the parts are good. It worked before shipping.

    Look for mechanical things.
     
  9. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
    1,190
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    What about finding some in the USA to receive it and then send it to them ???
     
  10. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
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    What's this brokerage fee? In my vast experience (selling one item to one Canadian) there was no such thing as a brokerage fee that I was aware of.
     
  11. GRNDPNDR

    Thread Starter Member

    Mar 1, 2012
    435
    7

    it seems to only apply to anything shipped over the border by UPS. I've never encountered it with any other shipping company. They sum it up as the cost of duty, taxes, etc.

    It's complete bull#$@! as far as I'm concerned. I'd rather pay a higher shipping cost than have to pay an extra $94 at my door to get my package.

    I am working through it with the seller, and maybe they can refund the total amount of money I paid in which case I would be happy.

    Failing that I asked if internal boards were available separately as a service option.

    If I end up stuck with this you can be sure I'm going to tear it apart and check as much as possible, but I may not be able to obtain a schematic.

    a good set of pictures can actually be found here
    http://www.eevblog.com/forum/reviews/mastech-hy3005f-3-power-supply-teardown/
     
  12. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    I never heard of "brokerage" fees. Should be unit price plus shipping. Period.

    In the US, Amazon offers free buyer protection as part of buying through them. You should not be getting screwed o a new item purchase through them.

    Ebay maybe, not Amazon.
     
  13. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
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    That does not guarantee a fix. The power devices on the heatsinks are often what blows up.

    You also won't be able to get the parts since everything now is made in China and many of the ICs are custom made for the device and not industry standard parts.
     
  14. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    That is definitely a specious assumption.
     
    rc3po likes this.
  15. GRNDPNDR

    Thread Starter Member

    Mar 1, 2012
    435
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    Are you U.S.? Have you ever purchased anything from Canada shipped by UPS??

    I completely hate it, and this is the kind of thing that happens to Canadian buyers all the time.
     
  16. Veracohr

    Well-Known Member

    Jan 3, 2011
    552
    76
    I don't think I've heard the term 'brokerage' before in that context, but I'm familiar with the concept. I usually hear it called 'tariffs' and/or 'duties'.
     
  17. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
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    I do buy stuff from canada and I have never heard of a brokerage fee, nor would I ever pay one. I would use a different carrier.

    By coincidence, Canada is where I get a product to add to milk which is an enzyme that converts the lactose so it can be digested. It's pricey, I remember it was from canada because I used payPal and it converted from canadian dollars to US dollars.

    http://www.digestmilk.com/lacteezexl.html
     
  18. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    Tariff is a whole different story. Has nothing to do with UPS, that is governmental fee.
     
  19. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,363
    Can you post photos of the front panel and inside circuit boards?

    If we can locate the circuit schematic there is a good chance that the problem can be identified.
     
  20. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
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    Not suggested from knowledge, but from experience.

    I repair a lot of doa"s. Odds are in favor of mechanical issues.

    ie. switch/relay/plug contacts, bad solder joints, broken trace/wire, etc.
     
    Metalmann likes this.
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