magnum s 980 bias setup?

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bluebird9894
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Joined: Friday 11th Feb 2011, 11:19
First Name: mitchell
Location: nl,canada

magnum s 980 bias setup?

Postby bluebird9894 » Friday 11th Feb 2011, 11:23

i have to replace the finals in my s980 , one of them split into,,i cant find the bias set up for this radio,,only the S9s and older s980,,,mine has the 0619r4 board and it does not have the shorting board at TP8---TP9,,can u help with bias set up.i have new erf2030s ordered just need bias set up,,,thanks mitchel

bluebird9894
Newbie
Newbie
Posts: 3
Joined: Friday 11th Feb 2011, 11:19
First Name: mitchell
Location: nl,canada

Re: magnum s 980 bias setup?

Postby bluebird9894 » Thursday 17th Feb 2011, 10:42

Magnum S9, S980 with 0619R4,0619R6 PCB Bias adjustments

Set the radio to SSB. Mic Gain fully counter clock wise.

Remove the jumper at TP9 and install a DC milliamp meter across the two pins. Press the PTT and adjust VR11 to obtain 20-30 mils of current draw with no modulation. Re install the jumper.

S980 radios only = Remove the jumper at TP8 and install a DC milliamp meter across the two pins. Press the PTT and adjust VR20 to obtain 50-60 mils of current draw with no modulation. Re install the jumper.

Remove the jumper at TP7 and install a DC milliamp meter across the two pins. Press the PTT and adjust VR10 to obtain 80-90 mils of current draw with no modulation. Re install the jumper.

The bias is now set correctly.It is critical that the 2 final ERF 2030’s have the same letter code(Vgs) and the ceramic insulators are 1.6mm thick. The amplifier will fail if the insulators are thinner than 1.6mm.

thanks sam lewis


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