Why can’t I see the trace on my WFM90/90D?

Why can’t I see the trace on my WFM90/90D?

Usually when the waveform or vectorscope trace is not visible it is because of one of the following 3 reasons:

1) The trace has been shifted left, right, up or down off the edge of the screen and can no longer be seen in the center of the display.

2) The display brightness is turned too far down.

3) The trace intensity is turned too far down.

An all three cases above, the quickest solution is to restore factory defaults on the instrument. This process will return any shifted traces to the middle of the display, restore the display brightness to default levels and restore the trace intensity to default levels. To restore factory presets, follow the instructions below:

1) Turn the WFM90 or WFM90D on.

2) Press the “config” button to bring up the instrument configuration menu.

3) Press the leftmost menu selection button (the unmarked grey buttons immediately below the LCD screen) until the “preset” menu is selected.

4) Press the rightmost menu selection button to recall the factory preset.

The above steps assume that the config menu was not left open the last time the instrument was used and that the cursor position in the config menu was left at the top. Since the instrument stores its last-used menu and position within that menu, you may find that pressing the config button actually closes the config menu (if it was already open) and that 8 rows down is not the correct offset within that menu (depending on the starting cursor location). This can be especially problematic if nothing at all can be seen on the instrument’s screen. If you cannot see anything on your screen to verify that the menus are appearing correctly then you may have to push buttons blindly a few times to recall the factory preset. The following procedure should (eventually) recall the factory preset even if the screen cannot be seen:

1) Turn the WFM90 or WFM90D on and have it running from the AC power adapter to ensure that steady power is applied.

2) Dim the lights in your room to minimize glare off the LCD screen.

3) Press the “menu” button. This will either open the “menu” menu (closing any other menus that were open at power up) or will close the “menu” menu (if it was left open at last power down); in either case it ensures that the “config” menu is not open now ( as it may have been at power up).

4) Here’s where we have to start guessing since we don’t know the last position of the cursor within the config menu. Alternate pressing the leftmost menu selection button (the unmarked grey buttons directly beneath the LCD screen) to choose a config menu item and pressing the rightmost menu selection button which will recall the factory preset if we’re in the preset menu.

5) Repeat step 3 until the factory preset is recalled and you can again see the screen or you have repeated it 12 times. If you have not successfully recalled the factory preset within 12 iterations of step 3 then something is wrong with your instrument and it needs to be sent in for repair.