Step 3: Making the modification

Picture of Making the modification
C:\Documents and Settings\kouttron\Desktop\INVERTER2 BROKEN FET.jpg
C:\Documents and Settings\kouttron\Desktop\inverter3.jpg
C:\Documents and Settings\kouttron\Desktop\INVERTER MOD1.jpg
Using a solder sucker / copper braid / a brillo pad (whatever works for you) remove the existing mosfets for the DC-DC converter. Try not to destroy the pads on the board!

carefully reinstall you new fet's. re-solder back in and reattach to any heatsink.

at this point (when everything is disassembled) its a good idea to give it a trial run.

1. make sure the surface your working on is free of conductive debris.
2. attempt to power up the inverter. (use a current limited source like a power supply/ wall wart if possible, not a car battery)
3. carefully check the output voltage (set meter to vac and check the output side)
4. if the output is 100VAC, try a simple 100W lamp.

5. note, i take no responsibility if you blow up you laptop/ house/ solar-system by following this instructable. prolly not a good idea to plug in an expensive laptop, but a blender / lamp / electric pencil sharpener / your 386 can take a beating and are less finicky to odd power supplies.
WileyS14 months ago

I wonder if anyone trying this has found an adjustment inside for lowering the allowed input voltage before the inverter faults out? I have the exact same Whistler model and it drops out at about 11.5 volts. It would be nice to be able to run it down to 11.0 or so. (It's set at 11.5 so joe six pack doesn't ruin his car battery by running the voltage down. A lead acid battery can be permanently damaged by taking it down below 11 volts.)

wlucas14 years ago
Most inverters today have good mosfets already mounted, (1000W inverter uses 4x100A mosfets). Its usually the small transformers that take the beating. (Source: Experience). Anyone done a transformer hack? :+)