L-1011 Trainer Installation: Light Plate Power-Up - Continuation

L-1011 Center Console - Light Plate Power-Up

Today was a busy sim building day. Jim Blasco and myself mounted the 5VDC 120A power supply we talked about in the last posting into the simulator and cabled the supply to the circuit breaker boards. While this sounds like a pretty tribal task, it actually took us several hours to it it all into place.

Certain groups of light plates as well as in some cases single light plates have their own circuit breakers. For example, the aft center console light plates are split over to different circuit breakers located on the CB2 panel.

Below shows the first F/E station light plate that is now permanently cabled in; it is the light plate for the Electrical System panel.

L-1011 Electrical System Panel - Light Plate

L-1011 Trainer Installation: Initial Light Plate Power-Up

L-1011 Light Plate Power-Up

I finally got my hands on a nice and compact 5VDC 120A power supply for the instrument panel light plates. Almost every panel in the Lockheed L-1011 cockpit has a backlit light plate that illuminates the legend on the plate. The power for the Light plates is 5VDC. Due to the fact that there are so many of them and that they use incandescent bulbs we needed a supply that can output a lot of Amps for the 5V required. Today we tested the power supply with 4 panels on the overhead panel: We powers up the Captains Windshield Wiper panel, the Exterior Lights panel on the eyebrow and the Interior Light panel also located on the eyebrow. Some of the light plates need some of the bulbs replaced, but, that's to be expected when dealing with 40 year old flight hardware.

The plan is to have all over the overhead and center console light plates powered up over the coming weekend.

L-1011 Trainer Light Plate Replacement

L-1011 Trainer Instrumentation to Real Flight Hardware Comparison 

The panel front plates on the L-1011 Cockpit Procedure Trainer are not back illuminated. Not having light plates on a trainer is pretty typical. However, for the simulator we are building at the museum we do want to have back-lit light plates because it will make for a much more exciting and interesting experience in the simulator.

In the image above you can the see the trainer front plate for the Engine Anti-Ice panel as it was made by Singer/Link; on the right hand side you can see the original Engine Anti-Ice panel as removed from a BWIA L-1011. Besides the slightly mismatched font, the two plates look very similar. Lets take a closer look at the two.

The plate on the trainer is a machined metal plate that has a picture pasted on the front. The machined plate is exactly the same size and shape as the actual light plate, but is slightly thinner; see images below:

L-1011 Trainer Metal Face Plate with Laminated Picture

L-1011 Trainer Metal Face Plate - Backside

L-1011 Plate Thickness Comparison (L) Sim (R) Real Hardware

The metal plates are cool, however, as discussed earlier are not what we want for the sim. Hence. we will either use the actual flight hardware with the illuminated faceplates, or move the light-plate from the real flight hardware to the trainer component. The complication with moving the plate, however, is that we also need to drill the power connector for the light plate since there are no provisions made for the connector on the simulated components (see image below).

Again, the positive is that the drillings for the mounting hardware are in the exact right locations and with the right screw pitch. Below are two images that show what the actual Lockheed light plate for the Wing Anti Ice looks like:

The silver screw looking times are the actual lamp holders. This allows for the light-plate to be re-lamped without the need to pull the PCB off the backside of the light plate. 

Restoration: Typical Light Plate Damage

After 20+ years on the line and, in many cases, spending almost as much time sitting in the desert, many of the light plates show both heat damage and damage to the paint due to dry conditions. On thing that is somewhat unique to the light plates used on the Lockheed L-1011 is that they are not engraved, but printed. In other words, all the legend was screen printed onto a white translucent layer of paint with the grey/blue cockpit panel paint used on the Lockheed L-1011.

The two main types of damage to the large paint areas can be seen below.



Most typically are edge damage to the plates around the instrument edges or instrument inserts. What happened there, is a basic chipping off of the paint due to mechanical stress such as dumps in transport, bumps during the de-installation and rough-handling while on the line. You will find, that most L-1011 cockpit panels required extensive plate touch-up work, especially around the instruments and edges, even while on the line and in day-to-day use.

The second type of damage that you can see above is a type of thermal (heat) stress that was caused by the plate back-lighting while on the line and to some extend to heating and cooling of the cockpit environment while it sat in the desert. Sometimes these cracks are called spider cracks because they resemble a spider net. In extreme cases, the cracks will originate from a darkened area in the paint that was caused by the bulb heat of the light behind the plate. The image below is a perfect example of that concentrated heat damage:


I will show the process of re-painting and re-lighting the original plates in a later posting. But for now, let's take a closer look at how the plates are actually lit. The electromechanical part that lights the acrylic plate, is screwed into the backside of the plate and comes off by simply removing a few screws.


The front-side of the plate shows the actual bulbs, a small plastic diffuser around them and the copper trace that creates the electrical connection for the bulbs.

The bulbs themselves are a very clever design and are meant for easy replacement on the line. Actually, to replace the bulbs the plate never had to be taken apart because the bulbs screw into the socket as seen below.




For the restoration effort, the idea is to replace the 5V incandescent bulbs with LED lights. I will show how to do that in a later posting.