My second selfmade linear with two GI7B

In February 2013 I start with my second linear with two GI7B. I was finish in May 2013.

I made experiments with microwave oven transformers. The problem is the overheating of this transformers. This transformers was build for impulse usage, and not for a permanent use. So I find a circuit in the internet from a other OM. He control this transformer with a LM393 IC. But you need a big transformer from a Moulinex Microwave oven.

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I build a cooling case for the two tubes

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The back side with the fan on the cooling case

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The under side with the input circurit

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The front side with the two tubes and Plexiglas

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Inside the linear. The roller induct-or is under the metal slide with the PI-Filter.

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The front of this linear

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The power and header switch

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The roller induct-or with counter

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The external power supply

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Inside the power supply. This is a microwave oven transformer.  He is controlled by a integrated circuit.

SSB Max
The maximum output on 80m SSB.

You can make 800 Watts with this linear on 80m SSB. It works fine for a long time.

Here you can download the schematics for the power supply: netzteil-2GI7.sch

Here you can download the schematics for the RF part: HF Teil. 2GI7

Lastrelais 2
This is the connection plan for the regulated microwave power supply

Lastrelais
This is the control schematics for the regulated microwave power supply

It works with a microwave oven transformer, but the power supply make a noise like a beating heard, when he is regulated the voltage 🙂

I sold this linear, after a longer usage.

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