Topics in Category: Falcon 50 - Rotate.Aero Wed, 23 Jan 2019 01:55:23 +0000 MYOB /media/kunena/images/icons/rss.png Topics in Category: Falcon 50 - Rotate.Aero en-gb ATA 33-10, Instrument Lights - by: Mark
I was asked to replace two light control potentiometers, Instruments and Side/Center on the cockpit right side overhead.

The pots are quite easy to change. All four knobs off, light plate separated, and one mounting nut on the pot itself.

Neither potentiometer was bad. The Instrument light knob was loose which prevented a hard stop on either the high or low side. A new pot was tried on the Side/Center wiring connector, but the problem remained.

The instruments involved in this case were the three Fuel Flow indicators and the three Fuel Quantity indicators right below the flows. (I'm not sure about Falcon's thinking on this, the upper instruments are controlled from the Left/Center knob on the pilot's side..... couldn't they have been combined the center instruments under "one" control knob?)

Also affected were the right side panel lights.

Now...... the fun begins. There are no Right/Center (nor Left/Center) wiring diagrams that matched this aircraft's effectivity. Actually, I couldn't find this system under "any" effectivity. No 7-1/2 amp breaker was shown on any print either.

When the lower knob was taken off the lower stop (starting turning it clock-wise) a faint click was heard behind the jump-seat located aircraft right. I've been back in that area before and knew there were quite a few relays and circuit cards.

By feel..... I isolated the relay in question (I had to remove three before finding the actual one). 84L2 was energized by the switch.

After digging back through the prints..... this relay was shown under the "Pedestal" lighting system. WDM 33-11-00.

After that things went quite quickly. The lighting power supplies are in the radome.

Blown fuse on center supply.

Borrowed one from another supply. One bright flash from the instruments and then nothing. The center power supply plug would reach the left without removing them. The lights worked correctly after the swap (normal hook-ups shown in image).

Bad center power supply, plus an extra fuse for the good one that I smoked.

In hind-site, I should of gone to the power supplies first and fixed it without prints at all. It just sucks that when you do use them and they're wrong it can kinda stretch a job out way longer than necessary.

Falcon 50 WDM 33-10-00]]>
ATA 33 Lights Fri, 29 Jun 2018 03:38:00 +0000
ATA 24-30, DC Power - by: Mark
I need to shoot the complete box (shit-loads of diodes). Still thinking issue is with one of GCU's. Busted my red pin pusher, as the easiest way to T/S would be to punch pins out off plug one at a time. "Then" isolate the faulty circuit if it is downstream from the box.

When I supposedly un-assed the GCU's..... I didn't. I disconnected them from the mounts, thinking they were rack mounts, but when I reinstalled them and safetied, I noticed there were cannon plugs on the back..... not rack plugs. So I never really removed them from the system. Too damn tired to go ripping back into the aircraft that day.

This issue is not a safety of flight problem, as all electrical functions operate normal; external power (when on), APU gen, all three engine gens.]]>
ATA 24 Electrical Power Fri, 16 Mar 2018 01:23:10 +0000
ATA 34-20, Falcon 50 Standby Horizon - by: Mark ATA 34 Navigation Fri, 13 Feb 2015 01:24:11 +0000 ATA 24-20, Falcon 50 Electrical Power - by: Mark

Swapped cards 14X1 and 14X2, no help.
Swapped cards 401J and 402J, no help.
Swapped relays 4X1 and 4X2, again..... no help.

(Jumpseat removed to gain access to right junction area.)

Dropped overhead and shot switch, both contacts good.

(3X1 shown, 3X2 just to the right, but out of picture)

Pulled card 14X2 and grounded pin 6, annunciator went out. This proved that power through diode and card 402J was good.

Also verified that 115VAC and 26VAC outputs were good (at least with meter).

Swapped inverters (that were NOT in nose and NOT under rear cockpit floor, but behind the galley, major pain in the ass to find).
The problem followed.

Even though the #2 A/C bus was powered, the indicator showing 115VAC, and my meter also showing good voltage...... the inverter output did not satisfy card 14X2 as being good. Possibly an o-scope might of shown a signal problem, but this problem was quite perplexing because everything was showing to be good.

Falcon 50, ATA 24-20
Wiring Manual 24-20-00
ATA 24 Electrical Power Thu, 08 Jan 2015 17:49:10 +0000