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powertech inverter 24v to 240v sine

 
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bbp1



Joined: 04 May 2007
Posts: 22

PostPosted: Tue May 29, 2007 7:25 am    Post subject: powertech inverter 24v to 240v sine Reply with quote

any circuit info on this nightmare?All major comp removed replaced as nec- still same -shuts down 2 secs"o,load". Sad Sad
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Guest






PostPosted: Thu Jun 07, 2007 11:53 am    Post subject: Reply with quote

Check if there are any current measuring shunts (low-ohm resistors) on the 24 V side, most likely connected in series with the emitter/source of power transistors, and that those resistors haven't changed values. Beware that there are sometimes several such resistors in parallel.

For measuring such low resistances (probably between 0,01 ohm and 0,5 ohm), a four-wire resistance bridge should be used, not an ordinary DVM.

If you find a suspect low-ohm resistor, then try to figure out which kind of fault could possibly have caused a current surge through it (shorted semiconductors etc), and double-check suspect components once more.
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bbp1



Joined: 04 May 2007
Posts: 22

PostPosted: Tue Jun 19, 2007 8:10 am    Post subject: Dc to ac inverters Reply with quote

Thanks Guest for your suggestion re lo ohmic res- have measured using 2 different lo ohm testers- appears to be spot on at 0.02 ohms- the whole goddamn problem is I can,t get circuit, or info, or even repair book, as you can with tv etc- so I have r/p/checked ALL COMP INCL 19 ic- many hrs spent- STILL THE SAME- WHY,WHY did I take this mongrel on- another repairer could,n,t fix after months- I have even wrote to maker (Pakistan) - no reply naturally- I saw a website where 100,s of posts were about "circuit-please". My suggestion to all is not to touch these- you can,t win unless a simple fault. Evil or Very Mad Twisted Evil Rolling Eyes Wink Shocked
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