ASCU technical discussion

[coach]

your selector plate is still contacting the cut off lever in F/A. you need to trim a bit more on the selector plate

[audi_bhoy]

Actually, I think it is more the third contact on the switch (The long one), outside the gearbox isn't touching the selector plate's metal piece, so it thinks it is still in semi. Bend it towards the outside of the box a little so the SP touches the contact arm.

[coach]

Originally Posted by audi_bhoy

Actually, I think it is more the third contact on the switch (The long one), outside the gearbox isn't touching the selector plate's metal piece, so it thinks it is still in semi. Bend it towards the outside of the box a little so the SP touches the contact arm.

but if it thought it was in semi, it wouldn't it continue to cycle in semi? since the cutoff lever should be able to move freely in both positions, it should act exactly the same as if the 3rd contact is not engaging the selector plate.

[audi_bhoy]

Well, if it doesn't buzz and still does semi shot after shot, it's the 3rd contact arm, otherwise, if it does one single shot and then buzz, it's most likely the cut-off arm, IMO...

[battleXtar]

is the below true??

I'm still trying to understand the whole relation between the SP + cutoff lever :

• Semi mode: SP touches 2 prong lever spring & not engaging the cutoff lever, cutoff lever moves freely??
(my case its shooting 3 burst in semi mode...)

• Full auto: ?? SP touches 3 prong lever spring & engage the cutoff lever, now the cutoff lever is being push by the SP to the top max??
(mine is not shooting in full auto - my SP not engaging the cutoff lever at all...)

[audi_bhoy]

The SP shall never touch the CO lever with this unit. If your semi shoots 3-round, most likely the 3rd contact is touching the SP, and needs bending away from the SP.

[battleXtar]

OK, that make sense..

Now lets go the the sensor unit... Inside the gearbox, the cutoff lever engages the sensor (dark grey color) arm by the sector gear's cycle, the cutoff lever's arm go almost at the sensor's highest point, leaving almost no gap it this point of the cycle... At the idle state the the cutoff lever rest with about 15mm gap from the sensor arm.. Is this correct?

[Jughead]

Hello Gents.

I have the 1st generation ASCU and it works like a dream.

I have now installed the 2nd generation ASCU and am having an issue on semi auto.

The gun will cycle once or twice before stopping and seems to seize up. But once I put it into 3 round or FA, it works fine?! Once I have fired it on 3 round bursts or FA, I can again cycle the gun in semi once or twice before it seems to get confused.. If i keep pushing the trigger enough times it will do a full cycle.

So..

I figure its not the battery or motor as it shoots perfectly on 3 round and FA.

Is it the cutoff lever or selector plate? or is it something else? Has anyone else had a similar situation?

[coach]

I haven't seen the gen 2 yet but it would be the same process as the gen 1.

remove the spring and cycle the gears. watch for switch and cutoff lever movement. do the same thing watching to see if the cutoff lever contacts the selector. check the 3 leaf springs on the back of the switch for proper contact with the selector plate.

[cetane]

I had to mod my selector to reliably get semi & auto to work as selected. When I went from safe to semi I had nothing. Move a little past semi and it engaged ok. Full auto at times worked. What I did was pull the metal off the selector plate and shave down the end towards the front of mechbox and slightly trim the metal so when I put it back on the selector plate, the metal was about 0.5mm closer to rear of mechbox. Now all modes engage properly.

I just now should replace the motor with a high torque one to help with braking. It at times over runs after burst holding nozzle pulled back.

[Mjosr7]

Problem: Fire select lever in SAFE, it fires a single shot.
: fire select lever in SEMI, It fires a single shot.
: fire select lever in AUTO, It fires 3 round burst.
: Return fire select lever to SEMI it fires 3 round burst.
: In mode 3 (single fire 3 round burst)

Does not malfunction when the gearbox is removed from the lower receiver.

I have put electrical tape on the inside of the lower receiver where the 3 exposed contacts may touch the receiver and on the two exposed parts of the contact on the selector plate. Disassembled and reassembled many times.

Anybody have similar issues or any insight to what could be the issue??


I am new to the forum.
First AEG...KWA sr7 with ASCU gen2. Very resilient MOSFET. Want to upgrade when this issue is solved.

[audi_bhoy]

Might looks like your contact plates on the switch are too bent, or the gearbox isn't sitting where it should, and the SP is not in proper position due to that.

[Mjosr7]

Looks like the tolerance between the selector plate contact is really close to the contacts to the ASCU contact pins. I didn't want to bend the pins so I pushed the contact on the selector plate as far forward and than puta drop of C.A. Glue to keep it in place.

I also put a small bead of C.A.Glue on the right side edge of the selector plate contact.
Gonna see. Hot that works out.

Thanks for the input Audi_Bhoy..

[venture]

GRRR....Just installed a Gen 2 and when I powered up for first time it beeps to signal that it is ready, then does nothing. Nothing in semi or full auto. The metal of the selector plate is obviously connecting the 2 and the 3 lamellas.

Anyone know what is going on here?

[Jugglez]

Communication problems between the sensor unit and brain usually means one or more contact pins on the data cable connectors (either end) are either damaged or come loose.

There are 4 wires on the data cable, each wire is a signal for one of safe, semi, 3round burst and full auto.

If the brain successfully beeps the motor on startup but one or more fire modes are not working i would be looking at the data cable before anything else.