Technical Hacking For Military Equipment

Read The Disclaimer

LRAS3 Power Supply (110/220VAC) and Battery Info

The LRAS3 (Long Range Acquisistion Scout Surveillance System) is a high end sight that was originally intended to be primarily mounted on Scout HMMWVs. It comes with a dismount cable and two battery boxes that take six rechargeable SINCGARS ("5590") batteries each. As fielded, it was never conceived that units would want to permanantly dismount the system. If you are viewing this webpage, then obviously you realize that this sight is often dismounted, and that the battery boxes are a poor, if not impossible method of keeping the sight running.

Interim Solution: Use the New Tan Colored BB-2590 Batteries in the Boxes

Chances are you're using the older, green colored BB-390 rechargeable batteries in the dismount kits. If the batteries are in good condition, each box will run the LRAS3 for about 2.8 hours. However, if you switch to the new tan colored BB-2590 batteries, you'll get almost six hours of runtime. So go get yourself the correct batteries.

The only issue is that the BB-2590 won't charge in the older PP-8444 chargers. You must use one of the newer chargers. The good news for you is that there are two charger options, and one of them is Class 9 (meaning it's easy to get). Below is the NSN information that you'll need to upgrade your LRAS runtimes by almost 4 hours per box.


BB-2590 NSN: 6140-01-490-4316	PP-8498/U NSN: 6130-01-495-2839 Class 2	PP-8481B/U NSN: 6130-01-527-2726 Class 9

Complete Solution: Get the Final AC Power Supply System from the PM

The Program Manager (PM) for the LRAS3 is currently in the process of fielding a cable and power supply to address this operational shortcoming. If you aren't in a rush, your best option is to email a request for the cable and power supply. Send an email to: ken@warfightersolutions.com and I'll try to get in contact with the correct entity at PM LRAS3.

However, if you are in a rush, or don't have time to wait for contact, then wait for approval and shipment, you can create your own solution using parts you and your BN already have. Below we show you how to help yourself.

Make Your Own Power Supply Solution

The following shows you how to hack and power the LRAS3, safely, and reliably, by only "modifying" Class 9 items (two cables) and using a standard military NSN power supply (PSU) already in the system; your commo shop should be able to get a hold of the PSU. It's too easy.

Extra Note/Warning: This solution hack is really easy. If done correctly (not hard to do), you can safely and reliably power the LRAS3 from AC power. If you screw it up (get your power backwards), you can fry a $460,000 sight. So, you know, you might want to get permission from the commander first... Additionally, never connect both a battery box and the power supply to the cable at the same time; while it should not hurt the LRAS3, it may damage the power supply

Tools

Soldering Iron

Solder

Flux

Wire Stippers

Voltmeter / Multimeter with Continuity (Bell) Function

Supplies

Part	Military PN and NSN
Electrical Tape	N/A
24V DC Power Supply Your BN Commo Shop should know where to find these, they are part of your unit's MTOE	PP-2953D/U, 6130-01-522-3494, or PP-6224C/U, No NSN as of 08/06, or PP-6224B/U, 6130-01-223-0267, or PP-6224A/U or PP-6224/U, 6130-00-133-5879
DC Output Cable for PP-6224	Many varieties, e.g. 5995-00-466-0217 (one of many possible cables, ask your commo shop for whatever they have on hand)

Directions

1. Cut, Strip, and Prep DC Output Cable

Cut the cable near the end with the female connector; you want to retain the male connector (with the pins sticking out) and most of the cable length. Strip back the outer shielding to expose the separate, inner wires. Depending on the cable, there may be two, three, or four wires inside; it really doesn't matter. You need to identify the positive and negative wires.

The positive and negative wires will most likely be the red and black wires, respectively. However, it is important to verify this by confirming the continuity with the multimeter. Positive is pin B on the male connector and negative/ground is pin A on the male connector. Again, positive is pin B and negative/ground is pin A. Mark the wires correctly if you think you'll forget.

Cut away any other wires and stip back the positive and negative wires about 3/4 inches.

2. Cut, Strip, and Prep LRAS3 Y Cable

Strip back the outter shielding on the main branch of the LRAS3 Y cable about 5-6 inches above the Y junction. Do not cut the cable itself, just strip back that outer jacket and shielding to expose the inner wires.

Definitely confirm, but it's likely that the white wires are positive, the black wires negative/ground. The green strips aren't wires, so don't bother checking and just leave them. Strip back a small amount of the jacket cover of each of the wires inside to expose the wire: you'll use this exposed wire to both determine what each wire is with the multimeter, and to attach your preparted Power Supply DC Output Cable.

Using the multimeter to check continuity, identify the wires that you've stripped back as positive or negative/ground. Do this by checking continuity at the connector that connects directly to the LRAS, not one of the two connectors that connects to a battery box. On the LRAS3 connector: A, B, and C are negative/ground. D and E are postive. F is unused.

3. Connect the Two Cables

Now that you've identified which wires in each cable are postive (LRAS3: D, E; Power Supply Cable: B) and negative/ground (LRAS3: A, B, C; Power Supply Cable: A), wrap the postive wires together, the negative wires together, and solder.

Confirm that you've done it correctly: use the continuity test function on the multimeter to confirm that pin A on th power supply cable rings pins A, B, and C on the LRAS3 connector. Confirm that pin B on the power supply cable rings pins D and E on the LRAS3 connector (the one that connects directly to the LRAS, not the the battery box connectors).

Use copious amounts of electrical tape to seal up your project, first separately wrapping the positive and negative bundles, then wrapping the entire cable tightly. If available, use zip ties to tied the two new cables together so that stress isn't put on your new joint.

4. Set the PP-6224/PP-2953 Output Voltage and Reconfirm

If you have an older PP-6224, you'll have to select your input voltage (110 or 220VAC). Plug in the power supply and turn on the AC power switch (right hand side). Next, turn on the DC power output; ensure that the gauge selector is switched to 'volts'; the needle should register an output voltage.

Attach your new DC output cable to LRAS3 input connector to the PP-6224/PP-2953 power supply. Using a small screw driver on the trimpot for voltage adjustment on the front of the power supply, tweak the output until you get a reading between 26 and 28 VDC on the LRAS3 input connector, and triple check that your positive and negative connections are correct! Technically, the LRAS3 can take in from 22 to 34 VDC, but an input of 26-28 VDC is playing it safe.