757 TQ wiring

[jackpilot]

Just got my 757 TQ Levers
Figuring out the wiring with a multimeter


Appears that Microswitches for the TOGA are always on, and off when button is pushed.
Switches wires for reverse and A/T do not respond to contact test.

I just tried on one lever, maybe some wires are interconnected ?


Jack

[bernard S]

hi JP   i am not really your huckleberry for this one... Matt is your man as he has that TQ 

[jackpilot]

Do you mean Matta757 or Matt Ford


Jack

[bernard S]

matt wull reach out to you 

[Nat Crea]

Appears that Microswitches for the TOGA are always on, and off when button is pushed.

Nothing wrong with that Jack. Just assign "off event" as your "on"

A/T Disco is a bit worrying, But your Reverse levers should be connected to a Pot not switch as in the NG?

Nat

[tomenglish2000]

Hi Jack.

The AT Disco switches are not independent. The A/T Disengage CMD signal goes from the depressed Disco switch through the unpressed Disco switch.

When the switches are both not depressed, an A/T Disengage reset signal is passed through the switches to the TMC (Thrust Management Computer).

These signals are grounds.

Nat, on the 757/767 the reverse levers drive the normal throttle linkage back below the forward idle position. There is no separate reverse linkage. The forward lock is integrated into the levers themselves.

Hope that helps Jack.

Tom.
757/767 Sim Builder.

[jackpilot]

It does indeed..
I have it figured out but the reverse microswitch
I located the switch (sandwiched in between the casing but it is not physically activated by the reverse lever, like something was missing.
Besides Could you tell me what these two guys are for, they do not move when the reverse lever is cycled, should they ?


Jack

[tomenglish2000]

Hi Jack,

Happy to help.

Those two little things are the lever reverser locks. When you pull the reverser lever up those pop out and hit against a piece of guard metal.

These serve two functions,

When the regular levers are forward of idle, they hit against the guard metal and prevent you from pulling the reverse levers. Otherwise the throttle linkage would reduce throttle away from the main lever position.

When the forward levers are in idle, they extend behind the rear of the guard metal when pulling the reverser levers and that prevents you from pushing the main levers forwards while the reverser is deployed. The forward levers are locked in the idle position by this until the reverser levers are stowed.


I am not familiar with the reverser switches. Can you post a picture? The only ones I know of are in the AT microswitch pack but I think that is on part of the throttle linkage below the floor near the clutches.


Tom.
757/767 Sim Builder.

[jackpilot]

REV switches are inside the lever (arrow)
Do you know the use of the "skate" circled in red on the left (friction device)?
Thanks for your input

Jack

[tomenglish2000]

Hi Jack,

I completely forgot those switches were there! I believe they are independent. Not sure why they arent working. Maybe the metal arm has come off them or the switch has failed or something. They should just work. I will have a look at my set over the weekend to see what mine do.

The "skid plate" is actually designed as cam that pushes a follower when either reverse lever is moved up to reverse idle and onwards to full reverse. The follower actuates a lever that raises the spoiler handle out of its down detent so that the spoiler motor can deploy them. This ensures spoiler deployment even if they were not armed.

Phil has some shots from his throttle that show this:
https://www.flickr.com/photos/project75/5647285859/in/album-72157627311717046/
https://www.flickr.com/photos/project75/5647841532/in/album-72157627311717046/
https://www.flickr.com/photos/project75/5647278813/in/album-72157627311717046/

Tom.
767 Sim Builder.

[jackpilot]

I sorted the Reverser switch issue. Careful de-assembly and cleaning.

Do you Guys know where i can get a proper tool with prongs to loosen that bolt, I do not have that in my workshop and does not even know its proper name...

[Garys]

Look for Castle nut socket. You can by them online. I saw  a guy in the process of hacking a impact socket to fit these type of nuts but I didn't didn't stick around long enough to see if it worked.

Cheers
Gary

[jackpilot]

 
Thank you
That bolt locks the axis of the TQ levers and there is one smaller on the other side.
I suppose it is not metric
Where should I measure  to buy the proper size.

[matta757]

The AT Disco switches are not independent. The A/T Disengage CMD signal goes from the depressed Disco switch through the unpressed Disco switch.

Tom,

Not questioning you on this as it certainly sounds like that should be the case, but the way I've wired my AT disconnect switches they ARE independent of each other, each switch has its own input on my BUO836X board and they are NO configured (meaning you must press them to create the event, opposite of the NC TOGA switches).

I don't know why this is the case with mine, but Jack when I first got my TQ I had ZERO information to go off of for the wiring and just played around with the wires until I found a combination of wires that worked. I got my TQ first of everything I have and was before I had any concept of how to wire using the cannon plugs that they use in real planes, and so I had just cut the plug off and played around with the wires until I found the right combo.

Sorry I can't be of my help. Tom has explained everything else about the inner workings of the TQ in a spot on way, so I have nothing else to add.

Jack- can I ask why you want to take that castle nut off? That holds the whole thing together and makes installation of the levers quite easy, is there are reason you want to separate them?

Matt

[matta757]

Hi Jack,

I completely forgot those switches were there! I believe they are independent. Not sure why they arent working. Maybe the metal arm has come off them or the switch has failed or something. They should just work. I will have a look at my set over the weekend to see what mine do.

Ok so I feel like I should know this, and feel like an idiot for not, but what exactly are those switches even for? I don't have them wired in my sim at all, what's the function of them in the real plane?

Matt

[Garys]

initiates the thrust reverser control system

[jackpilot]

Jack- can I ask why you want to take that castle nut off? That holds the whole thing together and makes installation of the levers quite easy, is there are reason you want to separate them?

Matt

Hi Matt
First idea was to separate them to install a new axle allowing a clutch setup for friction, same as my actual TQ which has worked flawlessly so far.

Just an idea though,
How did you manage that friction factor because right now they revolve loose on the axle?
Jack

[matta757]

Jack,

Well since I bought my real 757 sim, I now have the clutch pack that gives the levers their tension. https://flic.kr/p/EDtKLg

But before I had that, I built a make shift clutch pack based on Edoardo and Valerio's design. You can check out Valerio's flickr page for pics... https://www.flickr.com/photos/78279080@N04/albums/72157650785641286

The slip clutches are attached to the arms, which are attached to the throttle rods that attach to the lever arm. Whatever you do, I would strongly advise against taking the levers apart. The way they are built and put together means a rock solid feel, there is ZERO play between them. If you separate them, all bets are off and you could end up with lateral play in the levers.

Matt

[jackpilot]

Thanks for the info, I will check it out carefully.
I thought of my original design (as per above) because it has no play either and works without rods or offset mounts.
Will take my time anyway..
Jack

[jackpilot]

Matt:
This X shaped bracket:


is used to hold the lever assembly inside the TQ I guess.
I have just one on the FO side
would you or someone  have one available?

[matta757]

Jack,

Yes that bracket mounts to the walls of the TQ. But there is one on both sides. I do not have a spare unfortunately. If you have no play on your design then it should be fine, I just know that from my own experience, treading lightly and trying to keep things in the OEM condition as much as possible.

Matt

[jackpilot]

Agreed.

[mickc]

I just know that from my own experience, treading lightly and trying to keep things in the OEM condition as much as possible.

Where were you a week ago ?

[matta757]

I just know that from my own experience, treading lightly and trying to keep things in the OEM condition as much as possible.

Where were you a week ago ?

I saw this picture in your other thread and was floored. Amazing work. I am assuming you took care to document everything. I didn't go quite as in depth (down to every little part) but I did disassemble and clean everything...

Matt

[tomenglish2000]

Not questioning you on this as it certainly sounds like that should be the case, but the way I've wired my AT disconnect switches they ARE independent of each other, each switch has its own input on my BUO836X board and they are NO configured (meaning you must press them to create the event, opposite of the NC TOGA switches).

Hi Matt,

Checked the WDM carefully and found the following:

Both the left and right A/T Disco switches have a path direct to ground for the Disco signal and so will work regardless of the position of the other switch. There is only one input to the TMC for this ground signal though, so if you wish you can put them together on your BUO836X and save an input. Sorry for the confusion.

The Disco reset signal is wired through BOTH switches to make certain that if either switch is pressed, the reset signal cannot be received by the TMC.

The reverser switches are the L / R THRUST REVERSER CONTROL switches (78-34-01). Module 985 (Thrust Lever Assembly). Left one is S5. Right one is S6. As Gary says, they initiate the stow/deploy of the reversers (and deploy/stow happens if a load of other inputs such as air/gnd relays, A/T switch pack inputs, DC bus sense, etc are present). For the simulation world, I don't think they will be used, no current software looks at this stuff. PSX simulates these inputs for the 747 based on lever angle anyway.


Thanks.
Tom.