EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: Palmsquirrell on April 18, 2014, 11:33:09 am

Title: Rohde & Schwarz FSIQ 7 Signal Analyser, screen not working.
Post by: Palmsquirrell on April 18, 2014, 11:33:09 am

Rohde & Schwarz FSIQ 7  Signal Analyser.

Unit powers up but screen does not turn on/display anything.

Is there a way to hook up an external LCD to check if the problem is with the screen?

Also does anyone know the Part# for the screen?

Thanks

Title: Re: Rohde & Schwarz FSIQ 7 Signal Analyser, screen not working.
Post by: tautech on April 18, 2014, 11:54:32 am

Usually there is an inverter for the CCFL backlight PS. If it is not working there will be no visible display.
Quick check for backlight problems is to shine a bright torch at the screen and look for an image "front lit". If a "front lit" image is present then fault find the inverter circuit.

They can be a quite simple free running RC push-pull primary or a more complex IC controlled type.
Another check is to hold a scope probe near the transformer and look for ~20 KHz oscillation.

Title: Re: Rohde & Schwarz FSIQ 7 Signal Analyser, screen not working.
Post by: KJDS on April 18, 2014, 12:00:19 pm

It could be the backlight or if it is the display then these are usually a generic type. A quick search of the net should find a replacement but you'll need to take the instrument apart to find the generic part number.