PSG-1: Systema Switch Relay Circuit installation

[ILLusion]

Looking for experienced responses on this matter:

I'm installing a Systema FTK-12 on to a user's PSG-1. He is deciding to stick with the crazy strong spring it comes with, so I'm highly recommending that the Relay circuit (that the FTK comes with) to be installed.

Thanks to the awesome Engrish that the Systema FTK came with, I can't seem to make heads or tails of the instructions.

Is there anybody out there who has successfully installed the relay circuit?

[mcguyver]

The relay circuit in those kits looks just like the ones that come with the PTW's. The 2 large silver wires that are alone at one end of the realy board are the input. The other 2 silver wires at the opposite end are the motor output and the small guage wires are the control input from the trigger.

There should be at least 2 control wires, one takes voltage to the trigger, and one returns from the trigger (switched leg) to apply gate voltage to the FET's. There are 3 wires on the board for the PTW's, but the third is supplying the negative half of the circuit to power the other board. This is not present in the PSG-1.

I would think it would be best to remove the stock wiring from the stock switch to the motor to allow you to use the stock switch to trigger the FET's.

[ILLusion]

Actually, there are only three wires coming off the relay circuit that I have.

The two silver wires come out at opposite ends.

Alongside one of those low resistance silver wires is a very thing red wire. The only part of the instructions that I could gather is that this red wire acts as the trigger and it attaches to the selector plate.

I have no idea where the two silver wire goes, and as far as I can tell, it seems like the entire wiring circuit gets reversed in the process of installing this relay.

Anyways, if it assists in getting me the assistance I need to install this, I can take a picture and scans of all documentation/parts...

Unfortunately, I'm not too familiar with MOSFETS, so I'm not willing to take a wild stab in the dark as to what wire goes where.

[mcguyver]

If the red wire goes to the selector, then it's getting (+) DC from the selector. That means that one of the silver wires must be going to your battery (-), and the other would go to motor (-).

You would then wire the motor (+) directly to your battery (+) and eliminate the motor's contact with the stock switch. This would allow you to switch the motor from only the Systema FETs and have no current flowing through the stock switch, except what's required to gate the FETs. The empty spot you now have on the stock switch would be your connection point for that little red wire.

Does that sound like the circuit reversal? You would actually end up switching the negative with this FET arrangement vs. switching the positive in stock form.

Besides, if you blow up the board, Redwolf has them for $48 U.S., lol!!!

[ILLusion]

it... sorta sounds like the circuit reversal. In any case, I'm pretty confused, but at least I'm understanding more how the old stock switch is integrated in to the circuit and its role in the system, thanks to your description.

I'd still like to get a more definitive answer, or better yet, a wiring diagram.

Systema includes one... but it's GARBAGE. It's actually a colour photo of a completed circuit... but it looks like they took it with a 0.5 megapixel WEBCAM and then printed it in 4-colours with a 72dpi 2nd generation bubblejet printer. I can't even tell what the parts are in the picture, nevermind the wire colours. lol!

As for the Engrish instructions, based on the grammar used, half of the steps are telling me to solder my soldering iron to the circuit. lol

[mcguyver]

As long as you know for sure which silver wire goes to your battery (-), then your set. You may be able to tell with a multimeter if you set it for "ohms" and put the red lead on the red wire and try the silver wire in turn. One will be a really high resistance, mega-ohms, and the other will be really low, probably 1.4 ohms or so. That low resistance one goes to the battery negative as it's the collector terminal. The other high resistance one, the emitter, goes to the motor.

That's how I remember it, but a good picture does alot too. Z-shot maybe?

[ILLusion]

Wasn't on Z-shot.

I sat down after clearing my mind by having a beer (yeah...) and read over the instructions again. Messing with the Engrish in my best Engrish-translation mind I could muster up, I think I figured it out.




And for confirmation, I searched Arnies and I came up with this:

http://www.arniesairsoft.co.uk/forum...howtopic=75531

Confirmed what I figured out. Gonna keep this thread around for a while because I know this question gets asked a lot.

[mcguyver]

I didn't think at all about the PSG having (-) present at selector. I kept thinking about a "normal" AEG switch configuration.

[ILLusion]

dammit. i'm staring at the diagram and i can't figure out why the black wire coming from the battery connector goes nowhere...

The first half of the Engrish instructions are decyphered with that diagram. I still can't really figure out the last half.

Here's what it says (diagrams not necessary. They're useless anyways):

[3]
(1) Cut off the red cord running from the back end of GearBox, on the verge of the connector with a nipper and peel off the 2~3mm of the coating. The connector and the black cord are not necessary any more.
(2) Cut off the red and black cords stored in the stock, on the verge of the connector closer to the fuse holder. Peel off 2~3mm of the coating from the red cord tip and insert it to the contractive tube with the red cord ([3] - (1) ), solder them and insulate.

[4]
(1) Cut off the silver cord (solely running from the opening) at 5cm from the device and peel off 2~3mm of the coating.
(2) Cut off the 18cm of the black cord processed ( [3] - (2) ) and peel off 2~3mm of the coating. Insert it to the contractive tube with the cord processed ( [4] - (1) ), solder them and insulate.

[mcguyver]

The black wire going from the connector is no longer needed. They should have photo-shopped it out of there. The circuit they show uses the FET's to drive everything, including the negative portion of the circuit present at the selector. The switch/selector now only drives the FETs, which then drive the motor and the negative line out from the selector.

You've got to think of it as simply as possible. As long as you know the collector and emitter wiring, the second diagram should be easy to implement.

[ILLusion]

My mission objective shifted for a moment there. Rather than just get this job done, my objective temporarily shifted to trying to decypher the Engrish... hahaha.

It finally made sense when I realized that the new circuit has one of the Marui (mini) battery connectors removed. This diagram is to make one complete circuit from switch all the way to the battery connector. Now it all makes sense...