LCD and Bezel Installation Notes



I posted this note on the AT Sprint Yahoo Group in answer to the responses to a request I had made for a bezel size for the KD1JV MBDC rigs 16x2 line LCD. It is reproduced here for builders who wish to install a bezel (aka escutcheon) on their projects.


Thanks to all who responded to my query about a bezel for the 16x2 LCD. The PRD250B appears to be the correct one, it's available from Digikey. click here for the product page.

Mounting the LCD behind the bezel and panel is a bit tedious but is easy enough. Long time QRPer and FB builder Dave Rogers, WB4CHK, details the process well. It is posted here with some slight changes on my part, and is posted with permission. Any mistakes are mine alone.

1. Selecting and preparing the Bezel: The inside cutout of the bezel is smaller than the overall size of the bezel, so the bezel size is selected by the opening size needed for the LCD to be used. Plastic masks can be purchased that fit against the LCD face plate to mask off the unused part of the LCD face, also color filters are available. Note that the snap in mounting attachments aren't used, and the "nibs" must be removed so the LCD can fit flush against the back of the bezel. There are also bosses at the corners on the back of the bezel that require removing. File them off so that the corners are square and the bezel will drop into it's opening.

2. Select and mark the LCD position on the panel: Position the bezel on the panel, ands using it as a guide, mark the inside of the opening for the LCD Window. It's important to realize that the LCD fits behind the bezel and doesn't protrude thru the bezel opening. The LCD opening is smaller than the overall bezel size so the cutout size is not critical, the Bezel flange will cover most cutting mistakes and ragged edges.

3. Cutting the LCD opening: The cutout size is larger than the LCD opening so that the bezel will fit into it and cover the raw edges of the panel. The actual opening size for the PRD250B will wind up being approx 2 3/4" x 1 1/16". Measure your bezel first, or check the data sheet for the recommended opening sizel. Using a Dremel, or the drill and file method, cut out the opening and file it until till the bezel just fits into the cutout. Install the bezel and tape it to the front of the panel by it's edges, leaving the opening clear of tape. The bezel flange will cover the ragged edges of the opening.

4. Preparing the LCD: Four 4/40 flathead phillips screws one inch long are used to mount the LCD. There are four mounting holes on the corners of the LCD pc board which need to be enlarged. Using a 1/8" drill, CAREFULLY drill them out to accomodate the 4/40 screws. Insert a screw in each hole, flat head toward the front of the LCD, and place a 4/40 nut on each screw, don't tighten the nuts yet. After drilling the LCD holes note that the screws are loose in the holes.

5. Installing the LCD: Place the LCD with the screws loosely attached on the inside of the panel. Hold it in place with one hand and look through the front bezel opening to center the LCD inside the Bezel opening. When satisfied use masking tape to hold the LCD in place.

6. Recheck to make sure the LCD is positioned in the center of the bezel opening. If not, recenter and retape it until you are satisfied with the position. Then place the panel face down on the bench, the screws will drop into place against the inside of the panel. Align them vertically, and adjust the position of the 4/40 nuts so the flat heads of the screws are just in contact with the panel. These screws will become the mounting posts for the LCD.

7. Place a drop of instant (cyanoacrylate) glue on each screw head. After it cures, remove the 4/40 nuts, carefully remove the masking tape, lift off the LCD, and also remove the bezel from the front of the panel. Add a dollop of epoxy to permanently attach the screws.

You now have an LCD ready front panel with a bezel cut out. At this point label, decal, paint, letter or otherwise decorate the panel as you desire.

8. Finish the installation:

Install the bezel with a drop or two of glue and hold it in place with masking tape until the glue cures. Contact cement, epoxy, instant glue all will work fine, White glue can be used if you think the bezel may needed for another project in the future, it will pop off easily. Again, note that the snap in mounting attachments aren't used, and the "nibs" must be removed so the LCD can fit flush against the back of the bezel.

Install the LCD by sliding it over the 4-40 screws and snugging the nuts down so the front of the LCD butts against the back of the bezel. Be very careful not to over tighten the nuts and pop the screw heads loose from the panel. Finger tightening will adequate in most cases.



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