Re: ic-7000 alc voltages on IC-1601 and Q1604

Steve W3AHL

Looks like I can't upload a file to the Group, so here a copy & paste of some levels I took In 2012 at a slightly different component:

Set your 7K to 14.2MHz, FM Mode, 100% TX PO into a dummy load. Measure ALC voltage at junction of R1624 and Q1606 with DVM or scope. With mic unkeyed ALC should measure about 2.88 VDC. With mic keyed it should be about 1.99 VDC and the ALC display should have all green bars on.

Change TX PO to 50%. With mic keyed ALC should be about 1.91 VDC and ALC display should have red bars on.

Change TX PO to 10% and ALC should measure about 1.86 VDC.

For reference, in SSB mode with mic unkeyed ALC measures about 2.76 VDC. With mic keyed and normal voice level (only 1-2 green bars on ALC display voltge is still about 2.76 VDC. Turn mic gain up and give a loud AHHHH into mic and ALC goes to 2.25 VDC and most red bars on ALC display should be on.

This gives you an idea of how little of a variation in ALC is used to control bias of the IF gain to control power output. Actual voltages will vary a little depending on overall TX gain, power supply voltage, temperature, etc.

Steve, W3AHL

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