PG506
The Tektronix PG506 is a 1 MHz calibration generator plug-in for the TM500 system.
There are (at least) two versions of the PG506. The older version has two relays that switch a low-pass (noise) filter into the 10V and below ranges. The new version just has a capacitor across the output for these ranges.
Common failure modes: For low or no output on the 20V-up ranges, Q270, Q280 and Q290.
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File:Tek pg506 left internal.JPG|PG506 Left Internal Tek pg506 left internal2.jpg|PG506 Left Internal File:Tek pg506 right internal.JPG|PG506 Right Internal Tek pg506 right internal2.jpg|PG506 Right Internal File:Tek pg506 late.JPG|PG506 Front File:Tek pg506a front.jpg|PG506A Front File:pg506_new.jpg|Newer version without filter relays <gallery>