Today I finished installing an 8.4 inch TFT LCD panel in place of the original green CRT in my HP 8714C Network Analyzer.
This mod should work for the 8714C, 8714ET and 8714ES as they all have a VGA out connector on the back.
I bought the LCD panel and VGA driver board from ebay for $80 USD shipped - the seller shipped the entire kit inside a foam crate, it was extremely well packed.
This is the specific auction
http://www.ebay.com/itm/191341791384 - I made a best offer to get the 80 dollar price.
The original green CRT runs off 12 volts and uses 1.2 amps of current. The LCD runs off 12 volts and uses 1 amp of current so power wise it was quite compatible.
The VGA out on the network analyzer is 640x480 @ 60 Hz which is the native resolution of the LCD which makes for a very sharp display.
The original green CRT is in a self contained metal cage that pulls out with the main power supply from the network analyzer easily. It is connected via a shielded 20 pin ribbon cable which provides ground, 12 volts, mono video, horizontal and vertical sync. The VGA output is only on the back of the analyzer. Luckily HP left 3 unconnected wires in the 20 pin ribbon cable which is exactly what I needed for the VGA red/green/blue signals. This meant the only mod to the main board itself was running 3 small coax cables with each of the colors from the test points near the VGA connector to the unused contacts on the ribbon cable.
Once the CRT was removed I was left with a nice metal cage to install the VGA controller and a small adapter board I threw together to translate from HP's 20 pin ribbon cable to the video and power inputs of the VGA controller.
I decided to install the board inside of a secondary metal box, it made mounting easy and adding an extra level of shielding is always a positive. The LCD panel is mounted to the same 4 frame bolts that held the original CRT using a pair of adapter brackets I made out of 1/16th inch aluminum. The brackets also allowed me to fine tune the position of the panel as well as adjust the spacing from the front cover.
Speaking of the front cover - the inside of it was molded to match the curvature of the original CRT. The only permanent change I made during this mod to the analyzer was to mill away the curves so it would sit flat against the LCD panel giving it a factory look.
The project so far has exceeded all of my expectations. One last step I plan to do in the future is switch the LCD panel from CCFL back light to LED. That will be one less switching power supply running. I can also make up a circuit using the original CRT brightness pot on the left of the analyzer to adjust the LCD brightness. I did test the radiated noise from the panel and in front of the analyzer with my spectrum analyzer before and after and am happy to report I am detecting no additional noise which will interference with test results.
I figure for the dollars invested this is a pretty nice upgrade. The original green CRT is very sharp and easy on the eyes but the LCD really gives the machine a much more modern look and some color which is nice - btw the colors are all adjustable.