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Old 03-26-2016, 03:07 AM   #38
Dannii
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Join Date: Mar 2010
Location: Adelaide, South Australia (originally from Geelong)
Posts: 5,598
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Well, it is almost time to plug in the Yammy and give it a test. I've been busy over the last few days so only just got time to finish building my dummy load today.

Here's a pic of it and the schematic. There's seven incandescent globes in this design with six of them switchable and the seventh one always in circuit. It also has a bypass switch to remove the globes from the circuit if the initial test passes.
I've used a 100 watt globe for the permanent one and 70 watt halogens for the switchable ones. That gives me plenty of options from 70 watts to 520 watts.

I also have a Panasonic Inverter Microwave oven here that I'm repairing for a friend. The inverter chopper transistor and the main bridge rectifier in the inverter circuit failed (these microwave ovens use a switchmode inverter for the 4KV supply to the magnetron in place of the usual iron core transformer and large HV cap/diode arrangement). You can see the failed components and the edge of the inverter PCB in the upper left of the dummy load photo.

Dummy Load


Schematic
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