Hi folks, I've completed construction of my Boeing 727 overhead project and now I've begun the wiring phase of the project.I know that these lightplates operate on 5VDC, but I don't know how much current is required to push this voltage for all of the lightplates wired in parallel. I've experimented with a 5VDC 900mA PS, but this will only light one lightplate normally at a time. When I wire up another one in parallel, the light output halves. It's seems like it's wired in series when this occurs and I've tried wiring them both ways but the outcome is the same. Some of these lightplates have up to eight or ten bulbs such as the hydraulics control module.My only assumption is that this power supply is not up to the task of supplying enough wattage or current to these lightplates all wired together. The problem is, I don't know what the wattage of the bulbs are to calculate a current requirement. Some of these lightplates are manufactured by Spectra-Lux and another company whose name escapes me at the moment, but neither company has been willing to provide any information on their products (how they are wired or what current requrements are)If anyone here has had to go through this to get their Boeing lightplates to all function as advertised, I'd sure like to hear from you.

It sounds like your power supply simply has too small a current rating. You don't have to match the current rating of the power supply exactly to the current demand of the lightplates. You only need to assure that the power supply's current capacity exceeds that of the lightplates. However, the PS voltage should match the voltage rating of the lightplates. Each lightplate will draw only as much current as it needs as long as the correct voltage is connected to it.You can power the lightplates individually from separate small PS's or collectively in parallel from a large PS.Mikewww.mikesflightdeck.com

Hi Mike. I've used your website extensively for ideas during my project. I even managed to build a real lightplate as Spectra-Lux builds them. Minus the engraving. I used the paper mask with one black mask and then a Boeing Gray mask on top of that. Turned out great.I did some further checking on the individual lightplates for current draw. The smallest panels with the least amount of bulbs is drawing around 150mA. The largest such as the hydraulics control panel is maxing out my little 900mA supply as measured on a Simpson VOM.I have also been in contact with Bruce Campbell who is restoring and living in a complete 727 and he concurs with you.A few minutes ago I placed a bid on a 5VDC 40A power supply on e-Bay. Guaranteed not to be DOA. This should more than take care of my current requirements. Well, I guess I'll get back to wiring the Korry indicators and switches for now.Thanks for the reply Mike.Regards,Michael

The 5VDC/40A power supply I won from e-Bay works just fine. No dimming of the panels and all are bright as they should be.I made up two more bus bars for +/- and wired the panels this morning. Wish I had a shot, but that'll have to wait.The only one I'm having a problem with is the Gables dual HF head. I haven't figured out the pin-out arrangement that powers the lightplates. These don't seem to be wired as straightforward as the Collins units or the Boeing modules.I wrote to Gables asking for some help.

I am not sure if your HF panel is same or similar as mine. I am afraid it require 28v power instead of 5v. I tried connect the 5v directly to the lamp (two lamps for the panel). It did light up, but not as normal (very dark). Then I test it with 24v, it works normally.I can power up all my ovhd panels backlite by one computer AT power supply.www.alkit.net

Thanks for the reply. I wrote to Gables asking if it might be 24 or 28VDC, but as I expected, I've heard nothing from them yet.Is your HF head a Gables unit? Mine is a G-3514.I thought I tested this lightplate while I had it apart to restore it, but I've done that to so many panels I can't remember if I did or not.I believe I'm going to remove the knobs and (re-)test the lightplate directly on 5VDC and see what's going on with this. I'd rather not blindly apply 24VDC without checking the lamps directly at the socket with 5VDC.If it is 5VDC and I can't figure out the pin arrangement I'll run wires directly from the jack on the inside of the radio and out of the case.

I received an e-mail from Ozzie at Gables Engineering this moring. In it, he included the pin out arrangement for the the J1 and J2 jacks.The 3514 does indeed require 28VDC to power the light plate and dial indicator lamps.I guess it's back to the Mouser catalog for some more hardware.

Sorry for my late reply. I need to see what type is my HF panel. But I believe they are the same or very similar since there is only one type of HF panel available (affordable) to builders in the market.There are also some HF panels use 5vdc for backlite, but they are just the panel, no hardware. I think of buying it for adding hardware to it. However, it doesnt worth to pay effort to a unit which cannot connect to FS.It would be good idea to convert the lamps to 5v. Less power, less heat, similar beautiful effect at night.You can see my HF panel here:http://alkit.fotopic.net/p16847950.htmlhttp://alkit.fotopic.net/p16621148.htmlwww.alkit.net

That's very impressive!I ordered a 28VDC/1A PS from Mouser yesterday. This was a much easier and cheaper fix than rewiring the unit for 5VDC. Not to mention faster.That's a great overhead you have. What Boeing is that from? B747?The B727 I'm using is a fleet installed model from Air France VA. I'm not sure which model it is, but I'm using the Probst panel and the HF doesn't work on it anyway. I bought HF head mainly as a filler and I know they did install these particular HF heads in the B727.I have seven scratch-built panels in mine that I'll be replacing as they become available on the internet.