PERUN P90 Airsoft User Manual

Perun for P90
(Tokyo Marui standard)
User and installation manual

P90 Airsoft

Perun for P90 replaces mechanical contacts in your P90 replica and provides lots of useful features. Optical and magnetic sensors allow to eliminate many moving parts, which are prone to damage, thus increasing the reliability. The elasticity of this unit gives you certainty, that even a replica made from parts made by different manufacturers will not have any incompatibility issues. Adaptive trigger control allows switching from a short trigger travel to a long one even out in the field, as well as fast firing in semiautomatic mode.
Reading this manual will help you fully exploit this unit’s potential and in case of encountering any problems, you can look for solutions to them here.

Manufacturer: Perun Tech Sp. z o. o. Barwicka 8 St. 60-192 Pozna, Poland
e-mail: info@perunairsoft.pl

Technical data

Recommended power sources
Perun for P90 works with any power source that provides a voltage between 7 and 17 volts and can deliver enough current to ensure smooth cycling of the replica. Li-Po and Li-Ion batteries with a nominal voltage of 7.4, 11.1 or 14.8 volts are recommended. It is also advised to use batteries with possibly high ,,C” parameter and capacity. This is safer for the battery, as it should not be working on the edge of its capability. In this video, we are showing why: https://www.youtube.com/watch?v=s8RKcIy810A

Capacity and the ,,C” parameter also influence the rate of fire of the replica: https://www.youtube.com/watch?v=5hO25aPvHcU

Compatibility with high-ROF and high-power builds
Perun for P90 can work with any replica, including highly tuned.

Compatible gearboxes, gears, and triggers
Perun for P90 works in P90 airsoft replicas made according to standard set out by Tokyo Marui company, and followed by many other manufacturers, like: ACM, Asia Tactical, Classic Army, Cybergun, Cyma, J Tactical and JG. King Arms P90 requires modification to the trigger board mount, while Novritsch’s SSR90 demands that the magnet holder be modified. Both parts are included with Perun for P90 and are made out of plastic.
P90 mosfet will not work in P90 replicas made by G&G and Krytac.
Please be advised, that despite our best efforts to provide reliable information, we cannot guarantee full compatibility for all the gearbox shells and receivers mentioned above. Replica manufacturers sometimes slightly change dimensions of their parts from batch to batch, bringing need for some adjustment or in extreme cases, making them incompatible with Perun for P90.
Perun for P90 works with any gearset, including DSG, TSG, short stroked, helical, non-helical, and with any ratio.

Electronic fuse
Perun for P90 has an integrated electronic fuse, which will automatically cut the power off in case of a short circuit or when a gearbox jam is detected. The fuse does not wear out when it is activated.

Battery connector type
Perun for P90 comes with an already soldered T-Plug connector (T-Deans).

Stand-by current consumption
Whenever the battery is connected, unit consumes 2 mA of current. While unnoticeable during normal play, it may deplete your battery completely and damage it, if you store the replica with battery connected for a week or more. Therefore, always remember to disconnect the battery after use.

Brushless motors
Perun for P90 works with BLDC motors like Option No. 1 or Warhead.
RoF reduction feature must not be activated when these motors are used!

How does it work?

Perun for P90 uses optical and magnetic sensors for the detection of sector gear and trigger. That provides great reliability, especially of the semiautomatic mode thanks to elimination of the original long cut-off lever, which is prone to breaking or wear in stock replicas.

Sector gear detection
Perun for P90 is using a custom cut-off lever (provided in the package) which works with the sector gear cam to transmit gearbox cycle information to a phototransistor (sensor) and IR LED diode, which work in pair as a barrier switch. When sensor and diode are obstructed by the cut-off lever, end of gearbox cycle is signaled to the unit.
The original cut-off lever must endure high stress when disengaging the contacts, exacerbated by high mechanical disadvantage resulting from its length. Cut-off used with Perun for P90 is only used for optical detection and is therefore not exposed to such stress.

Trigger
Perun for P90 is provided with an additional external circuit board (trigger board) that is installed near the trigger and connected with a cable to the main board fastened to the gearbox. Hall-effect sensors on the trigger board are monitoring the magnetic field generated by the magnet in the magnet holder installed on the trigger. These readings are then conveyed to the microcontroller of the unit, which depending on the sensitivity setting and trigger position, may trigger a shot. The magnetic sensors are also able to detect, whether an external magnetic object is present near to the replica and in such case, will activate external magnetic field alarm to prevent an unintended shot.
The trigger bar that in stock P90 replicas is used to transmit the trigger movement to the gearbox is no longer needed.

Selector
Selector position is not directly detected by the mosfet. Safe mode is provided by the selector by mechanically blocking the trigger. Semi mode (the first trigger stage) is provided by the selector only allowing the trigger to pulled back a certain distance when on “SEMI”. When on “AUTO”, the trigger can travel all the way back and that allows the electronic unit to detect both first and second trigger stage. The threshold for both stages can be set by the user according to personal preference.

Installation

1. Remove the upper receiver, gearbox, and the trigger bar (link between the trigger and the gearbox; shown on the photo below). Trigger bar will no longer be needed.

2. Remove mechanical contacts assembly with its wiring from the gearbox.

3. Remove the gearbox screw shown the photo below and insert the longest screw provided in the package (22 mm not counting the head) from the other side of the gearbox, fastening the main board to it. In place of the original cut-off lever, install the one provided in the package. Use the original spring and screw.

4. Secure the screw on the other side using provided nut and spacer, to make sure that gearbox is properly closed.

5. Use two 8 mm screws and nuts to secure the front of the gearbox.

6. Connect the motor.

7. Connect one of the signal cables to the gearbox. Put the gearbox in the body, making sure that the wires are going forward as shown on the photo below. You might find it easier, if you keep the body and gearbox upside down while sliding the gearbox in. This way the cable will pass through the opening more easily.

8. Install the back plate and fasten the control board to it. Use provided 12 mm screws.
   If your P90 replica has gearbox with quick spring change feature, control board must not be fastened to the back plate, but instead remain loose inside the battery compartment. The main reason is that gearboxes with QSC tend to stick out of the back plate. Because of that, metal parts of the gearbox or the spring guide can scratch the back of the control board causing a dangerous short circuit! Fastened back plate would also essentially make a quick spring change impossible.

9. Install the magnet holder. Use the fastening screw, but do not turn it all the way in, until you feel resistance! Make it only tight enough to make the holder sit still in the trigger. If needed, reinforce the connection using cyanoacrylate glue.

10. Install the trigger board, control board, and the holding piece in the receiver as shown on photo below.

11. Connect the cable to the trigger board.

12. Assemble the replica and the calibrate the trigger.

Trigger calibration

Trigger calibration is mandatory because it ensures proper functioning of the “SAFE” mode. However, if done successfully, it will also ensure that first and second trigger stages can only be accessed according to current selector position. This means, that no shots can be taken with the selector on “SAFE” and that second stage is not available with selector on “SEMI”, regardless of current sensitivity settings for each trigger stage.

Trigger calibration is performed the following way:

1. Enter the programming mode.

2. Go to “Trigger calibration” feature (LED blinking violet and blue alternatively).

3. Pull and hold the trigger for a few seconds to start trigger calibration. The LED should be emitting white, blinking light now.

4. Switch the selector to “SAFE”.

5. Pull the trigger very hard and hold it. It is necessary, because it tells the unit how far the trigger
   can travel when the selector is on “SAFE”. Should the trigger ever be accidentally pulled when on “SAFE”, the unit will take the slack in safety mechanism into consideration and will not allow a shot to be fired on “SAFE”.

6. While still holding the trigger and applying force to it, press the button on the control board. There should be a beep and the LED color should change to blue.

7. Release the trigger.

8. Switch the selector to “SEMI”.

9. Pull the trigger all the way and hold it.

10. Press the button on the control board. There should be a beep and the LED color should change to red.

11. Release the trigger.

12. Switch the selector to “AUTO”.

13. Pull the trigger all the way and hold it.

14. Press the button on the control board.

15. Then there should be a long beep and the LED should shine green for a couple of seconds.

The settings have been saved and the trigger is calibrated.
Should any time the control board button is pressed, a red light appear accompanied by intermittent beeps, the calibration was unsuccessful, and the changes have not been saved. This can happen either due to erroneous execution of the calibration, improper installation, or problem with the unit itself.

Adaptive trigger control

Each time the battery is connected, Perun senses the trigger resting position and uses it as a reference (therefore, make sure to never pull the trigger during startup). Depending on the current trigger sensitivity setting, Perun will automatically fire after the trigger has traveled a long enough distance. This allows short trigger pulls with no trigger modification needed whatsoever, and the trigger sensitivity changes possible even in the field. When in semi-only mode, Perun for P90 uses a progressive trigger activation method. This means that the trigger threshold and reset points are mobile and move together with the trigger, as shown on the sketch below:

Features and programming

To enter the programming mode, press the button on the control board two times. First push activates the button, which is signaled by LED starting to glow green. Quick second push shortly after the first leads to the programming mode. Successful entry into the programming mode will be confirmed by a sound signal and LED glowing green. Pressing the button will switch the modes, while pulling the trigger allows to enable, disable, or set levels for the modes.

Full feature description

Firing mode
| Choose firing mode combinations: semi, binary, semi-auto, semi-burst and burstauto. 1 st  stage is the firing mode activated after a short trigger pull. 2 nd  stage can be reached by pulling the trigger further and that should only be possible with selector set to “AUTO”.

Burst count
  Green and white blinking alternately| Define number of shots in a burst.
2-5 short signals and blinks – 2-5 round burst
AB Blue| Active brake (AB) stops the motor after the shot, preventing the spring from remaining in a compressed state and eliminates double shots on semi in replicas with high rate of fire (“overspin”). 5 levels of braking strength are available – from 1 (weakest braking) to 5 (the strongest). Braking can be also completely disabled. It is advised not to use braking or use it on the lowest level, if stronger braking is not necessary, as it negatively impacts the service life of motor brushes and causes increased heating.
Tip: Switch to semi, fire a single shot, and hold the trigger after the shot. This will cause a second single shot with strongest AB setting to be fired after 3 seconds, making sure the spring remains uncompressed. It is advised to do that when you finish shooting.
While precocking is on, the AB setting becomes irrelevant. However, any programmed AB setting will be stored in memory and will become effective as soon as precocking is disabled.
No sound signal while LED glows blue means, that the active brake is disabled. 1 to 5 signals indicate braking levels from 1 (the weakest) to 5 (the strongest).
Precocking

Yellow| When shooting on semi, precocking keeps the piston in the rear position, ready for the shot. This decreases the time between pulling the trigger and the actual shot, increasing realism, and giving advantage in CQB fights.
Correct precocking level must be set individually to each replica and according to user preferences. Precocking power is automatically adjusted to battery voltage and semi or automatic shots.
Tip: To release the spring after using precocking, switch to semi, fire a single shot, and hold the trigger after the shot. This will cause a second single shot with the strongest active brake setting to be fired after 3 seconds, making sure the spring remains uncompressed. It is advised to do that when you finish shooting.
No sound signal while LED glows yellow means, that the precocking is disabled. 1 to 8 signals indicate precocking levels from 1 (the weakest) to 8 (the strongest).
Trigger sensitivity – 1 st stage
Violet and yellow blinking alternately| This parameter governs how sensitive is the 1st  stage of the trigger. For instance, when semi-auto firing mode combination is enabled, this parameter decides how much trigger travel is needed to fire on semi. 5 sensitivity levels are available.
Since Perun for P90 depends on the mechanical trigger lock, make sure that when using highest sensitivity settings, pulling the trigger with selector on “SAFE” will not result in a shot! If it does, trigger calibration must be performed. 1 to 5 signals while the LED blinks violet and yellow alternately indicate sensitivity levels from 1 (the lowest) to 5 (the highest).
Trigger
sensitivity –2nd  stage
Violet and red blinking alternately| This parameter governs how sensitive is the 2 nd stage of the trigger. For instance, when semi-auto firing mode combination is enabled, this parameter decides how much trigger travel is needed to fire on auto. 5 sensitivity levels are available.
Tip: Choose such trigger sensitivity for the 2  stage, so that it can only be activated when the selector is set to “AUTO”. 1 to 5 signals while the LED blinks violet and yellow alternately indicate sensitivity levels from 1 (the lowest) to 5 (the highest). nd
ROF
  reduction
White| This function allows to lower the rate of automatic fire. 5 reduction levels are available:
1 – 6%
2 – 12%
3 – 18%
4 – 24%
5 – 30%
Those are approximate values and may vary depending on replica configuration.
 Semi-automatic shots and the first shot in burst are always fired without any power reduction to retain good trigger response.
No sound signal while LED glows white means, that the ROF reduction is disabled. 1 to 5 signals indicate reduction levels from 1 (the smallest) to 5 (the greatest).
Li-Po and Li Ion alarm
Teal| Li-Po and Li-Ion alarm informs the user that battery voltage has fallen below 3.7 V per cell, at which the battery should not be further used and must be recharged. Unit automatically detects number of cells in the battery and determines safe voltage range.
The need for battery replacement is signaled by short sound signals every 30s. Disable this function if you are using batteries other than Li-Po or Li-Ion.
No sound signal while the LED glows white means, that the alarm is disabled. 1 signal indicates activation of the alarm.
DSG Green and blue blinking alternately| This function can be enabled when dual sector gear is used, to provide better precocking control.
No sound signal while LED glows green and blue alternately means, that DSG is disabled.
1 signal indicates activation of the DSG mode.
Trigger
calibration
Violet and
blue blinking
alternately| More details in section 4. of the manual – “Trigger calibration”.
Master reset

Red| Master reset returns the unit to the factory settings.
To reset, pull and hold the trigger for 2 seconds or simply wait 10 seconds while the LED glows red and until the reset takes place without using the trigger. A long sound signal confirms return to factory settings.

Factory settings

New units and units where master reset was activated will have modes set in a following way:

• Firing mode – semi-auto
• Burst count – 3
• AB – level 3
• Precocking – disabled
• Trigger sensitivity – 1 stage – level 3
• Trigger sensitivity – 2 st stage – level 3
• ROF reduction – disabled
• Li-Po and Li-Ion alarm – enabled
• DSG – disabled nd

Diagnostic system

Perun for P90 has a diagnostic system that will help you find the source, should you encounter a problem. After the battery is connected, the unit undergoes a start-up check, to make sure replica is ready to work. Successful completion of this check is indicated by a short green blink of the LED.

provides information about the disconnection of the motor, but it is also a diagnostic mode for the trigger and sector gear sensors, as well as button on the control board.
With the motor disconnected, engaging the switches will cause the LED to glow purple (trigger), green (sector gear), or white (button) for a moment. This can be used for troubleshooting problems with the switchboard in the gearbox. Reconnecting the motor will restore normal function.
Motor check only takes place at start-up. A disconnection after the start-up will not be signaled!
Fuse activation Red, continuous, or blinking| Activation of the fuse with a distinction between a short circuit (continuous red) and gearbox jam (blinking red). In some situations, this distinction may not be correct, for instance, a gearbox jam may be incorrectly read as a short circuit and vice versa.
Electronic fuse might as well be activated by parts combination, which draws too much current (e.g., high speed motor and gears).
The unit will start functioning normally after the battery is reconnected unless there still is a short circuit that will be detected at the next start- up.
Gearbox cycle detection failure Yellow and green blinking alternately| The unit did not receive information about cycle end from the sector gear switch and stopped firing only after safety time limit was exceeded. Check whether the gears or the sensors are not damaged and whether the sensors are properly engaged by the gears.
Unit temperature is too high Yellow and white blinking
alternately| Too high temperature of the unit (main board) was detected. It will not function again until it cools down, after which it will operate normally.
Battery with too low voltage is connected Yellow and teal blinking alternately| Battery with voltage below 7 V is connected. Change the battery to one with voltage between 7 V and 17 V.
Battery with too high voltage is connected
Red and teal blinking alternately| Battery with voltage over 17 V is connected. The battery must be immediately disconnected, as it can cause permanent damage! Change the battery to one with voltage between 7 V and 17 V.
An external magnetic field was detected Red and violet blinking alternately| External magnetic field (originating not from the trigger magnet) was detected by the trigger sensors. The unit will be blocked until the source of the magnetic field is not removed.
Main transistor or driver damage Red and yellow blinking alternately| The main transistor or driver is damaged. The unit needs to be sent back for repair.
Battery voltage sensing malfunction Red and white blinking alternately| The battery detection system is malfunctioning. The unit needs to be sent back for repair.

Other known problems:

strong
for the main spring, which causes
an overspin.| Enable AB or precocking.
Too high precocking level| Set precocking to a lower level.
Trigger mechanism malfunction.| Check the cut-off lever and contacts, replace
if needed.
Replica does not shoot; the unit does not emit any light
or sound.| Incompatible T-Deans battery connector.| T-deans plugs and sockets from various manufacturers may sometimes not work together reliably. Although the plug may
seem to fit the socket nicely, the conductive surfaces may not contact each other, cutting the power off. In that case try with another battery, most preferably with a T-deans socket made by different manufacturer.
Battery and/or the
motor heat up very much.| The battery has too low capacity
(mAh) and/or “C” parameter.| Use a battery with higher capacity and/or “C” parameter.
The motor is too weak.| Use a stronger motor, with neodymium magnets.
Increased motor load caused by anexcessive friction, for example
caused by:
– improper shimming,
– motor positioned askew in the
pistol grip.| Remove the cause of the friction.
The motor/gear ratio/spring
combination draws too much
current (for instance – high speed
motor, high speed gears and M120
spring).| Change the replica configuration by using a softer spring, gears with higher ratio (lower speed, higher torque) or motor with higher TPA number (or lower revolution speed).
When trying
to shoot, replica
remains silent or shortly vibrates, after
which green LED appears and one beep
is heard| A gearbox jam or a short-circuit is
present but because of low battery
power or bad connection with the
battery, the unit resets due to
voltage drop instead of the
electronic fuse properly activating.| Remove the reason of the gearbox jam or short-circuit.
The build is too power demanding
for the battery use and the unit
resets due to voltage drop.| Use a higher-powered battery.
External magnetic
field error appears,
despite no external
magnet being close
to the replica| Trigger was being held at startup.| Reconnect the battery and do not hold the trigger during the startup.
The trigger has too much slack and can move sideways, which can activatethe error.| Shim the trigger so that it cannot move sideways, only back on forth.
The triggers movement is obstructed and when it is released, it may end up in
slightly different positions. If at some moment the trigger will move further back than it was at startup, this can
activate the error.| Make sure the trigger can move freely and completely unobstructed.
Use stronger trigger spring.
When RoF reduction
is enabled, electronic fuse activates, or the
replica just does not
shoot| The RoF reduction is too great, and the motor is not able to cycle the gearbox.| Reduce RoF reduction or disable it completely.
Motor beeps from
time to time| Li-Po alarm has activated.| Replace the battery (if you are not using a LiPo or Li-Ion, disable
the Li-Po alarm).

In case of any technical questions, please contact us at: info@perunairsoft.pl

Sensor check

You can easily check the sensor readings by disconnecting the motor. When Perun for P90 is connected to the battery, but disconnected from the motor, it informs about this by yellow, flashing light. If during that flashing a properly working and connected switch will be closed, the unit will signal that by changing the LED color for a moment.
To enter this mode, the motor must be disconnected first, only then connect the battery!
After you enter the sensor check mode, it will be active for 5 minutes, after which the unit will shut down. To restart it, simply reconnect the battery.

Disconnected motor / Sensor check

Yellow, blinking| None of the sensors detects any change at this moment.
Button on the control board
White| This should happen after button on the control board is pressed.
Trigger

Violet| Trigger pull detected.
Sector gear
| Sector gear movement detected.

Checking the trigger sensor can be done by simply pulling the trigger. To check the sector gear sensor, it is best to open the gearbox and remove everything out of it, except for the sector gear. Then spin the sector gear by hand and see, whether the color of the light changes to green.

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