[WSWSS] Need Mirage Alignment info

[Cliff Buttschardt]

Glen, the MIRAGE B3016 has a very poor bias adjustment circuit to begin with.
There have been distortion problems from the beginning!  If this is a recent
increase in distortion, check the wiper contact on the 100 ohm adjustment pot
near the final amplifier transistors (SRF3417).  There is a 3.3 ohm resistor 
across the pot with a 1N4002 that should also be checked.
     You may have lost a final transistor as well.  To check this put an ammeter
in the 12 volt supply lead, activate the EXT KEY and be sure SOME current is
being drawn.  Varying the 100 ohm pot should show a hundred mA of DC current
which can be varied by changing the pot position.  Activate the EXT KEY for a few 
minutes.  Put you finger on the top of the final transistors to be sure they are
equally warm.  Obviously the cooler one MIGHT not be functional.  Cliff K7RR

Dave Glenn wrote:
> 
> Hello All,
> 
> I have a couple of Mirage amps that I need to check alignment on. My 2 meter
> 160 watt has taken to sounding distorted even with very low drive. It is a
> 50 in 160 out version. Also have a 220 amp I would like to check out between
> contests. Any idea where I could get a service manual or alignment
> instructions. I am specifically worried about the bias adjustments.
> 
> Thanks,
> 
> Dave
> N6TEB
> 
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