inverter repair question

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bhva
bhva Registered Users Posts: 15
I have a StatPower Portawattz 1750 inverter (Yes, its old enough to have the StatPower nameplate) that just recently quit and I want to explore the options for repair.

When I connect it to a 12 source, but leave the loads disconnected (actually connected/disconnected, same result), within a couple seconds of turning it on, it indicates an overload and shuts down (I tried several 12 sources, cables, etc. same result in each case).

Anyone here that can tell me what's wrong with it? Whether its worth trying to fix it? Who might be able to fix it? Where I might be able to get service manuals/schematics for me to fix it?, etc.

Thanks

Brian

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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: inverter repair question

    I have a 600 Watt version, and it still works.

    But I doubt it's worth the time, effort, and money to repair one of these. For about $500 you can get a 1500 Watt Samlex sine wave inverter: http://www.solar-electric.com/sa15wa12vosi.html

    And if you look around on the 'Net you'll see some pretty big bargains in El Cheapo inverters both MSW and TSW.
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
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    Re: inverter repair question

    If it initially fires up, then shuts down on overload, that sounds like possibly one or more of the AC output switching FET transistors is shorted out. That would apply a heavy load/short circuit on the high voltage DC power supplied to those output transistors. I've seen and repaired several smaller inverters, including a Statpower 250 watt inverter that a friend left connected to the AC panel at his camp when he fired up his generator. The little Statpowers were very difficult though to get apart and back together due to the way the switching input and output transistors are internally clamped to the inside of the metal sleeve/heat sink. I've never personally seen a Statpower larger than 250 watts.
    By the way, I found the cheapest supply of output FETs was to purchase a low end cheap inverter of similar power rating, on loss leader sale and strip it for parts. :)
    BTW, the little 125 and 250 watt Statpower units that I have, are I think roughly 15 years old and have extremely low idle power consumption of roughly 20ma. Unheard of in more modern inverters!
  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
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    Re: inverter repair question

    Probably not worth the effort. Even Xantrex doesn't repair their new inverters here in the USA. When they get enough on a pallet, they ship them back to China for repair. If someone needs one fixed under warranty, they either receive one of the inverters that just came back, or they'll get a new one. But they won't get their original inverter back. Got this first hand from Xantrex.

    I've fixed inverters, but nothing more than either replacing a cooling fan, or an internal fuse. A coworker bought a dead Prosine 3.0, and it's a mess inside. Part of the issue is, if anything fries (as with his), it's very difficult to identify components, and the manufacturer isn't going to supply a schematic. FWIW, his had a fried row of FETs, apparently a common issue.

    dscn3353.jpg

    dscn3354.jpg

    dscn3349.jpg

    Replacing the componets is the easy part. Identifying, and possibly finding a suitable replacement for obsolete parts is a challenge.

    With that in mind, the Xantrex Prowatt SW2000 (1800W continuous) pure sine wave inverter is a good deal for $325 online.
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
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    Re: inverter repair question
    2manytoyz wrote: »

    With that in mind, the Xantrex Prowatt SW2000 (1800W continuous) pure sine wave inverter is a good deal for $325 online.

    Wish I could find one of those in Canada for anywhere near that price! $1249.00 is more like it here :cry::cry::cry:
    Sorry, just realized, you were talking "Prowatt", I was thinking ProSine.
  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
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    Re: inverter repair question
    Wish I could find one of those in Canada for anywhere near that price! $1249.00 is more like it here :cry::cry::cry:

    Sounds like you need a ROAD TRIP! Ouch...
  • bhva
    bhva Registered Users Posts: 15
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    Re: inverter repair question

    On-line is available from anywhere - I found them on e-bay in the $300s. Mind you @2ManyToys referenced the Prosine SW2000 not the Freedom SW2000 (which is in the $1200 range). When I have a job again, I'll may pick up one of those Prosine units. It does, however have one of those GFCI outputs, so it never work as the AC2 input on my XW6048 (since the neutrals are tied together - if only that auto-transformer was a true 120/240 converter). It would work for feeding the planned outboard 48v battery chargers using the 12 from my vehicles.

    I opened up my Portawattz 1750 and took a cursory look at the 33 FETs and there is no blackening on them like any of them had created its own inferno, but one (or more) could still be bad - to really test them, I have to undo a great many hex screws and remove the main circuit card. Before I do that, can anyone give me a FET test procedure that I can do without further removing the FETs from the board?

    Thanks for all the input,


    Brian

    Thanks
  • bhva
    bhva Registered Users Posts: 15
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    Re: inverter repair question

    Oops, my bad, its the "Prowatt" SW2000 that is in the $300's - on Ebay and at Amazon.

    Brian
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
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    Re: inverter repair question
    bhva wrote: »
    ..... Before I do that, can anyone give me a FET test procedure that I can do without further removing the FETs from the board

    Often FETs have been paralleled with no ballast resistors between them, makes it really hard to test.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: inverter repair question

    When electronic devices began switching from vacuum tube to solid state technology you would quite often find things with a label that said "No User Serviceable Parts Inside". These days they may as well put stickers on that say "No Matter How Good A Technician You Are You Can't Fix This Bloody Thing And Even If You Could It Wouldn't Be Worth The Time". :p

    Ah for the days of pulling out the valves and putting them in the tester, setting the controls to "12SK7" or whatever and seeing the needle move to "GOOD" or "BAD"!

    But there's no such thing as a "FEV" (Field Effect Vacuum Tube). :D
    (Don't bother to tell me that's how they all work; I know.)
  • bhva
    bhva Registered Users Posts: 15
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    Re: inverter repair question
    When electronic devices began switching from vacuum tube to solid state technology you would quite often find things with a label that said "No User Serviceable Parts Inside". These days they may as well put stickers on that say "No Matter How Good A Technician You Are You Can't Fix This Bloody Thing And Even If You Could It Wouldn't Be Worth The Time". :p

    Ah for the days of pulling out the valves and putting them in the tester, setting the controls to "12SK7" or whatever and seeing the needle move to "GOOD" or "BAD"!

    Alas, Good advice. I'm just a glutton I guess. Actually since I don't have work at present, time I have, money to replace I don't. This inverter is old school (not as old school as vacuum, mind you - It's all through hole circuit card with mostly discrete components), so I thought there might be hope. If it were surface mount and/or "system on chip" design (hard to do power that way of course), I would have given up faster.
    But there's no such thing as a "FEV" (Field Effect Vacuum Tube).

    Wouldn't that be "FEVT" (an ETLA - "Extended Three Letter Acronym")?
    (Don't bother to tell me that's how they all work; I know.)

    Wouldn't that be "... that's how they all work - all the ones that are left anyway ... " ?

    I've got a couple people that would enjoy pulling off the FETs and testing them. I'll just give to them and see if it ever comes back.

    Thanks for your help.

    Brian
  • BB.
    BB. Super Moderators, Administrators Posts: 33,479 admin
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    Re: inverter repair question

    Check control circuits too... It is not unusual for them to fail (check solder joints).

    I think one common problem is when FETs let loose--They take their control circuits out too (over voltage back feed).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
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    Re: inverter repair question

    Ah for the days of pulling out the valves and putting them in the tester, setting the controls to "12SK7" or whatever and seeing the needle move to "GOOD" or "BAD"!
    I may still have a couple of 12SK7's and perhaps a 5U4 or two as well. I'll trade them for one of those famous but mysterious "Power Tubes". Hahahaha
    Oh NO! The Power Tube is gone! :cry:
    But methinks we digress :D
  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
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    Re: inverter repair question
    bhva wrote: »
    Oops, my bad, its the "Prowatt" SW2000 that is in the $300's - on Ebay and at Amazon.

    Brian

    Here's where a few people I know have purchased theirs: http://www.hodgesmarine.com/Xantrex-Prowatt-Sw2000-2000w-True-Sinewave-Inverte-p/xan806-1220.htm

    I bought mine a while back from Camping World while it was on sale. Think I paid $349 at the time, but now they're only $325 at Hodges Marine.
  • PhilS
    PhilS Solar Expert Posts: 370 ✭✭✭
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    Re: inverter repair question
    2manytoyz wrote: »
    Here's where a few people I know have purchased theirs: http://www.hodgesmarine.com/Xantrex-Prowatt-Sw2000-2000w-True-Sinewave-Inverte-p/xan806-1220.htm

    I bought mine a while back from Camping World while it was on sale. Think I paid $349 at the time, but now they're only $325 at Hodges Marine.

    I bought one of those to power my Sanyo mini-split (and from Hodges Marine, too) and although it had a continuous rating of 1800w, the surge rating didn't seem accurate, It would be at 1600w and switching on 100w of lighting would 'brown-out' the Sanyo and our TV and the sat receiver, putting them all into "restart". Then I put the inverter in our RV (replaced an old ProSine 1K) and it will not power our microwave at all, which is 1500w (1000w 'output').

    A little disappointing, but it was only about $350.

    Phil
  • BB.
    BB. Super Moderators, Administrators Posts: 33,479 admin
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    Re: inverter repair question

    Heavy enough/short enough DC input wiring (i.e., was it DC input or AC output that was browning out)?

    -Bill

    And battery bank capable of supplying needed current? -BB
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset