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Stealth · June 2nd, 2013, 21:42

Introduction

Lately we've been getting some emails regarding MOSFETs and how to install them.

In the Gate Electronics manuals, which can be found here, it refers to two types of installation methods.

The guide below outlines Method #1 - installing the MOSFET without replacing existing wires. I was installing a NanoAB, but the procedure is identical for a MERF3.2 and very similar for a PicoSSR. For PicoSSR guide, click here.

Tools Required

Soldering Iron (30W or 40W iron will do)
Solder (Get something with flux core)
Multimeter

Installation Procedure

Step 1: Figure out where you want to put your MOSFET. NanoAB and MERF3.2 are usually confined to inside buffer tubes or handguards due to their size. With the PicoSSR, I've managed to fit one inside the mechbox itself.

Step 2: Get to the trigger assembly. I'm assuming you know what you're doing if you're reading this. There's lots of guides out there on gun disassembly.

Step 3: Clean your trigger contacts and the trigger sled. Even after some minor use, electrical arcing will cause the contacts to pit. Using some 600 grit sandpaper, gently sand the contacts to remove all visible marks. In the image below, you can see distinct discolouration and carbon buildup on the trigger sled and one of the contacts.

Step 4: Desolder the red wire going to the battery and join it to the red wire going to the positive motor terminal. It doesn't really matter which wire gets desoldered, but doing it this way gives you more clearance for the trigger to move.

Step 5: Solder the signal wire to the other trigger contact which you had freed up in Step 4.

Step 6: Reassemble the trigger assembly into the mechbox and see if your wires are interfering with the trigger and the safety lever. Reposition and adjust if necessary. Once you are happy with the product, shrink wrap the exposed wires.

Step 7: With the NanoAB and MERF3.2, all you need to do is to plug in the Deans connector and the signal wire. For the PicoSSR, you will need to solder the negative wires and signal wire directly to the circuit board. Make sure the negative battery wire is connected to the contact patch with the transistor pins, and the negative motor wire is connected to the opposite contact patch. Orientation matters.

Testing Procedure

While it's possible to test with the trigger assembly installed in the mechbox, it can be a bit difficult unless you have a helper. I would just take it out.

Note: The battery SHOULD NOT be connected during this procedure. If you connected your battery and attempted this, you will start a fire somewhere.

Step 1: Switch your multimeter to measure Resistance. Short the two probes and see if it reads 0 ohms. If it doesn't, make a mental note of this number and add it to your readouts.

Step 2: Push the trigger sled in between the contacts. Touch one probe to the positive battery terminal and the other probe to the signal wire. The resistance should be less than 10 ohms. If it is greater than 10 ohms, clean your contacts and check your wiring. It may need to be replaced. When you're done, pull the sled back out.

Step 3: Touch one probe to the positive motor wire and the other probe to the negative motor wire. Your multimeter will display OL (overload), Open Circuit, or some really big resistance value (i.e. 20 MOhms). If it displays anything less, you have a short circuit. Double check your wiring for rips or tears in the insulation. If you're confident you don't have a short, give us a shout.

Step 4: Push your trigger sled into the two prongs so that there is contact. Make sure it stays there. Repeat the measurement for the two motor connectors. Again, it should read OL, Open Circuit, or 20 MOhms. If it doesn't, you have a short somewhere. If you're confident you don't have a short, give us a shout.

That's it folks. Once you've completed all the tests with the multimeter, plug everything in. The signal wire plugs into the top pin of the NanoAB and MERF 3.2.

With the MERF3.2, don't forget to program it first, or your gun will start shooting automatically the moment the battery is plugged in.

June 2nd, 2013, 21:42	#1
Stealth Mr. Silencer Trader rating Join Date: Dec 2001 Location: Toronto	Airsoft Store Canada presents - Installing a Gate MOSFET Introduction Lately we've been getting some emails regarding MOSFETs and how to install them. In the Gate Electronics manuals, which can be found here, it refers to two types of installation methods. The guide below outlines Method #1 - installing the MOSFET without replacing existing wires. I was installing a NanoAB, but the procedure is identical for a MERF3.2 and very similar for a PicoSSR. For PicoSSR guide, click here. Tools Required Soldering Iron (30W or 40W iron will do) Solder (Get something with flux core) Multimeter Installation Procedure Step 1: Figure out where you want to put your MOSFET. NanoAB and MERF3.2 are usually confined to inside buffer tubes or handguards due to their size. With the PicoSSR, I've managed to fit one inside the mechbox itself. Step 2: Get to the trigger assembly. I'm assuming you know what you're doing if you're reading this. There's lots of guides out there on gun disassembly. Step 3: Clean your trigger contacts and the trigger sled. Even after some minor use, electrical arcing will cause the contacts to pit. Using some 600 grit sandpaper, gently sand the contacts to remove all visible marks. In the image below, you can see distinct discolouration and carbon buildup on the trigger sled and one of the contacts. Step 4: Desolder the red wire going to the battery and join it to the red wire going to the positive motor terminal. It doesn't really matter which wire gets desoldered, but doing it this way gives you more clearance for the trigger to move. Step 5: Solder the signal wire to the other trigger contact which you had freed up in Step 4. Step 6: Reassemble the trigger assembly into the mechbox and see if your wires are interfering with the trigger and the safety lever. Reposition and adjust if necessary. Once you are happy with the product, shrink wrap the exposed wires. Step 7: With the NanoAB and MERF3.2, all you need to do is to plug in the Deans connector and the signal wire. For the PicoSSR, you will need to solder the negative wires and signal wire directly to the circuit board. Make sure the negative battery wire is connected to the contact patch with the transistor pins, and the negative motor wire is connected to the opposite contact patch. Orientation matters. Testing Procedure While it's possible to test with the trigger assembly installed in the mechbox, it can be a bit difficult unless you have a helper. I would just take it out. Note: The battery SHOULD NOT be connected during this procedure. If you connected your battery and attempted this, you will start a fire somewhere. Step 1: Switch your multimeter to measure Resistance. Short the two probes and see if it reads 0 ohms. If it doesn't, make a mental note of this number and add it to your readouts. Step 2: Push the trigger sled in between the contacts. Touch one probe to the positive battery terminal and the other probe to the signal wire. The resistance should be less than 10 ohms. If it is greater than 10 ohms, clean your contacts and check your wiring. It may need to be replaced. When you're done, pull the sled back out. Step 3: Touch one probe to the positive motor wire and the other probe to the negative motor wire. Your multimeter will display OL (overload), Open Circuit, or some really big resistance value (i.e. 20 MOhms). If it displays anything less, you have a short circuit. Double check your wiring for rips or tears in the insulation. If you're confident you don't have a short, give us a shout. Step 4: Push your trigger sled into the two prongs so that there is contact. Make sure it stays there. Repeat the measurement for the two motor connectors. Again, it should read OL, Open Circuit, or 20 MOhms. If it doesn't, you have a short somewhere. If you're confident you don't have a short, give us a shout. That's it folks. Once you've completed all the tests with the multimeter, plug everything in. The signal wire plugs into the top pin of the NanoAB and MERF 3.2. With the MERF3.2, don't forget to program it first, or your gun will start shooting automatically the moment the battery is plugged in. Last edited by Stealth; July 21st, 2013 at 17:56..