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Restoration on a Budget: Seneca Power Control Panel Upgrade

Restoration on a Budget: Seneca Power Control Panel Upgrade Featured

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December 2014-

Here we are again!

Things surely didn't start out this way. I'd retired in March of this year and was looking for a simple project to consume a week or two in the summer and allow me and my dog to hang out at the airport with a purpose. The result of that simple goal was a restored throttle quadrant, and it looked incredibly good.
That was quite a rush, and all of my hangar neighbors were quite impressed. Then I noticed the de-icing panel looked even worse than the throttle quadrant. That was my second project. (Readers can refer to the July and October 2014 issues for Sherer's articles on restoring the throttle quadrant and de-ice control panel, respectively. —Ed.)
Having a really nice-looking instrument panel in my Seneca II recently led me to the conclusion that the power panel had to get upgraded, too.
So here we are again. Now that this project is complete, I can tell you it was much more challenging than the first two. But it, too, looks really good—even though it's not factory-perfect.
I discovered that my skills and experience only go so far, and I've lowered my expectations for future projects just a bit. If you're not qualified to attempt this project alone, enlist the help of your A&P.
Take a look at photo 01 and you'll see that my airplane had a power panel that looked like the north end of my southbound dog. Perhaps you can relate. Compare it with photo 06, you'll likely agree the project was worthwhile—and even though it's not the easiest thing to accomplish, I'd do it again. And I'd recommend that you do it, too.
My friends are saying my airplane looks about 35 years newer—quite a compliment. Now if I could just get the outside painted...

Step 1: Information gathering
If you're doing your Seneca power panel, figure about $800 for parts and supplies. If you're doing your Saratoga, Lange or Six, figure $400 or less. Simply put, fewer switches equal lower cost.
Since I wanted all new switches in the panel—with engraving I could read—I pulled out my trusty Piper Seneca II Parts Manual. If you don't have a parts manual, I'd recommend buying one. There is, in my opinion, simply no way to own a Piper without one. They're inexpensive, and can be obtained online. (See Resources on page 29 for information. —Ed.)
I've included my list (see page 29) to assist you in sourcing parts. However, you must cross-reference each part number you're ordering against the parts manual for your model. Getting a part number even one digit wrong can cause confusion and errors.
Obviously, if you're doing this project for another model of Seneca or a Lance, Saratoga or Cherokee Six, all parts must be checked against the parts manual. I can confirm that the strobe or pitot heat switch in one model is not the same as an identically-titled switch in another model.

Step 2: Placing the order
Be very careful with the part numbers. Between shipping expenses, restocking fees and the time lost on the project, triple-check each part number before placing an order. (This is also a great opportunity to use Piper Flyer Association's parts locating service to your advantage. It's free with your membership, and just takes one call to 800-493-7450 to get the ball rolling. —Ed.)
I've listed the vendors from which I purchased these parts. (Refer again to "PA-34 Parts Inventory and Vendor List," on page 29.) If you have a different vendor that you're comfortable with, by all means, work with them. I encourage you to take your time on this phase of the project.
Upon receipt of each part, verify that you have received the right part number and take a close look at the part to make sure that it is what you were expecting. I transcribed an incorrect part number for a strobe switch in my Seneca, and although I still received a strobe switch, it was the wrong switch for my plane.

Picture 1


Step 3: Removing the old panel
First—and this is paramount—go into your forward baggage compartment and disconnect the red positive battery wire from the battery using a crescent wrench or socket set. DO NOT SKIP THIS STEP.
You can do this entire project while sitting in the pilot's seat and doing so will allow you to put your tools and parts on the copilot's seat and floor without the risk of bumping in to them. You will also be at the correct height and position to remove and replace the panel. (Removing the front seat(s) and sitting on the floor doesn't work well at all—I've tried it!)
If you look at picture 01 you will notice that there are 10 screws placed around the perimeter of the panel. The two at the top are different than the other eight.
Starting at the bottom and sides, remove the first eight screws and put them together on the floor in front of the copilot's seat. The two screws at the top should be removed last. You'll need these screws again much later unless you have a new stainless steel screw kit.
When the last screw is out, the panel will fall forward, so you should be holding the panel at this point. There is a wire bundle extending from the bottom of the panel which is strong enough to support the entire weight when you're not working on it. Let it fall over slowly while you're supporting it, and it will be okay.

Picture 3


Picture 2


Remove the plastic overlay from the actual switch panel backplane (picture 02). First, gently pull the two red primer switch caps off of the primer switches. They are pressure fitted and a gentle pull will remove them.
Next, remove the nuts from the primer switches. If there are any washers on the primer switches, remove those too, and store all of this in a neat little pile in front of the copilot's seat.
Above the landing light switch on the underside of the plastic overlay is a screw. Remove it. There is another screw several inches to the right of the landing light above the fuel pump switches. Remove that screw, too. The third and last screw is above the battery master switch. Put these three screws with the primer switches, caps, nuts and washers.
At this point you should be able to gently remove the old black plastic overlay from the switch panel backplane. Once you've finished this work, I suggest you take a break to stretch your back and give your eyes a break, too.

Picture 41


Step 4: Replacing the switches
Replacement of the switches is the easy part of this project. (Really!) Lay out your new switches on the copilot's seat. Pick up a new switch, any switch. Order doesn't matter, as they are all very quick to replace.
Find the old switch on the backplane. Above and below the switch to be replaced are two small Phillips screws. Take a medium- or small-ended Philips screwdriver and remove the screws. Keep these screws as the new switches do not include these screws.
Gently pull the switch backward from the backplane until it's sticking out in the back and accessible for replacement. Remove one screw and wire from the old switch. Connect this one wire to the new switch in the exact same position using a new brass screw. Repeat the process until the switch is done.
While most switches are single pole single throw (SPST), some of the switches are double pole double throw (DPDT), and in some cases not all terminals on a switch are used.
Hand-tighten each screw on the new switch. Gently press the switch back into the backplane location that it came from. Reinsert the Philips screws into the front of the switch and hand-tighten.
Now it's time to admire your work! See how nice the new switch looks? It's shiny and you can read the engraving. Then, just as it says on the shampoo bottle that I have at home, repeat.
Each rocker switch is very similar. Just remove each switch and replace each wire, one at a time. As for the primer switches, those don't have screw terminals and will have to be soldered. If you are able to do that, great. If not, have your A&P solder them for you. It's easy, only two wires per switch.
Replacement of the switches took me about four hours over the period of a week, and I did about three switches per visit to my airplane. I could only get a few done at a time before I would discover that I had the wrong switch, or had to purchase primer switch washers and paint them, etc. Little bumps in the road are standard.
If you find you have an incorrect switch, I recommend you stop what you're doing and order the correct switch right away, as it might take up to a week to get the new part. Then go back to installing new switches.
I kept my Seneca's alternator switches intact because they are expensive to replace and my old ones work just fine. Since they were toggle switches and not rocker switches, they had no worn-out engraving. I spruced them up (pun intended) with yellow switch caps from Aircraft Spruce. You can pick your color—and they were a whopping $1.35 each.
Also, you will notice that under my alternator switches are two press-to-test warning lights. My airplane came from Europe and required starter warning lights. Today, these lights are available with LEDs so I purchased two new red LED press-to-test lights from Aircraft Spruce. They look good and the LED lamps will last practically forever.

Picture 5


Picture 6


Step 5: Trim and paint
the new panel overlay
This part of the project I found to be very rewarding and not very difficult. However, my patience wore thin when trimming the switch holes in the new panel.
Compare picture 05 (page 31) with picture 06 (page 33). The new panel overlay comes in two pieces: the main overlay and the magneto switch cover overlay, each of which are ordered separately. In addition, there are two springs to order: they make the magneto switch overlay spring back to its original position when you move it.
On the old panel, I removed the two pivot screws and nuts holding the magneto overlay to the main overlay. (Save these screws and nuts because you'll need them on the new overlay.) Then I drilled five holes in the main overlay.
On the new magneto overlay I needed to drill two holes for the screws that were taken out of the old magneto overlay. To do this, locate the old screw holes on the old overlay, and mark the new overlay at the same location. It helps to cover the general area needing to be drilled with masking tape and mark the precise spot with a pencil.
Also, on the main overlay you will need to drill the same two holes for the same two screws. Mark the general area with masking tape and use a pencil to mark where the holes should go.
Look again at the old main overlay where the three screw holes are (where the main overlay mounting screws were removed). Put masking tape in those three general locations on the new overlay, and then measure as precisely as you can on the old overlay. Mark those holes on the new overlay, and be sure to check your work. Then you can drill the screw holes on the new main overlay.
Temporarily install the new overlay on the switch backplane. My guess is that the new overlay won't fit. I spent about four hours putting the new overlay on, taking it off, putting the old overlay on, taking it off and measuring and trimming the new overlay to fit the backplane.
I'll try to save you most of the four hours with this advice: it turns out that the supplier's cutting of the switch holes on the new overlay wasn't accurate for my aircraft. In fact (at least, on my overlay) you could see curved lines and horizontal lines in the holes. I spent hours filing, sanding and Dremel-ing these holes, a little at a time.
I'd figured the precut holes would be correct as-is, but this part of the project really took some work. However, once I was done, the overlay fit the backplane perfectly. After checking the fit, remove the new overlay and let's get it painted.
Both the magneto and main overlay need to be washed before painting. I decided to take them home and washed them with dishwashing detergent. After they had dried I put on two thin coats of Rustoleum Plastic Primer per the directions. I let the paint dry overnight, then put on two thin coats of Krylon Indoor/Outdoor Almond Gloss spray paint. (I like almond, but of course you can use whatever color you're using in your airplane.)
I again waited overnight for everything to dry and then, using my labeler, I copied the labels and placards from my old overlay and installed them on the new overlay. See picture 05.
Next, look carefully at your old magneto overlay. My guess is that both springs (which are located with the screws and nuts) have failed by now. Mine had rusted through and were broken. While half of the spring was on the magneto overlay and half of the spring was on the main overlay, they were still in the correct location, so I was able to replicate the position of the new springs on the new panel.
It is impossible for me to give directions in this article about how to do that. If you need help, I recommend you take the old and new overlays, springs, screws and nuts to your A&P and have him give you half an hour of his time. While I didn't find this overly difficult, I did need to stare at it a while until I figured it out. It was a bit tedious, but I got it right the first time.

Step 6: Install the new overlay
We're in the home stretch. Now is probably a good time to tell you that during the installation process you will scratch the new overlay. Not to worry, there's a way to touch it up after install.
You can expect good to above-average quality on this panel, as you're neither the manufacturer nor a professional restoration expert. But you and your friends will still be impressed, even if there's a little goof somewhere.
As you have probably done five times before while getting the new overlay to fit on the backplane, do it again. This time, though, be as careful as you can to not scratch the paint (but don't sweat it if you do).
While you're holding the overlay on the backplane, test the switches to make sure that they don't bind when you turn them on. If you have any binding, remove the overlay and break out the sandpaper or file. Then try it again.
When you're confident that the overlay fits, reinstall the three screws that were removed at the end of Step 3: one above the battery master switch, one above the fuel pump switches and one above the landing light switches.
If you had to enlarge the screw hole and find that now the screw head is smaller than the hole, use a washer or two from your screw kit. Do not tighten until all three screws are in.
Then reinstall the primer switches at the top of the panel.
Finally, reinstall the 10 screws that were removed toward the beginning of Step 3, and you're done!
Take a quick break now, because the smoke test is next.

Step 7: Smoke test
First, reconnect the battery. (Note: if the cable sparks when reattaching to the battery, something might be wrong.) After reconnecting the battery and replacing the battery cover in the baggage compartment, head back to the cockpit.
Say a small prayer and turn on the master. Your instrument panel should come alive, no breakers should pop, there should be no smoke (really!) and you should not smell anything.
Now you can test all of your switches to make sure they work. Some of these tests will have to be done at engine startup and runup.

Step 8: Touch-up
Have you scratched your brand-new paint? If not, consider yourself very lucky—but if you did, you'll need only two things to touch it up.
First is a small paintbrush, like you would use on a model airplane. I found a four-pack of these at my hardware store for two dollars. Next you'll need a disposable paper drinking cup, not a plastic cup (plastic cups melt when you spray paint into them).
Take your can of spray paint and put some in the paper cup. (Because of the mist/overspray, I'd do this outside, away from the airplane.) Then go back to your panel, and using the small brush, touch up whatever needs to be touched up.
Finally, take a picture and post it on the PFA forums for all of us to admire!

Piper Flyer Association member Scott Sherer is a multi-engine and instrument rated private pilot. He's logged 2,600 hours and is the owner of a 1977 PA-34-200T based at Burlington Municipal (KBUU) in Burlington, Wis. He wishes everyone good luck with their own restoration projects and is happy to offer his help; simply email him via the PFA forums. Send questions or comments to .

Last modified on Monday, 12 January 2015 23:21

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