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Cyma Cm.621 Upgrades

will take apart and give the sensors a clean incase any grease flicked offf onto them when i was test firing as trigger itself isnt sticking or binding is nice and free moving

the safety i think is more when its screwd together when the box is together thinkthe screw is pulling through the threads so think ill need to replace that to sort that issue

 
haha yeah i upgraded to the perun bud :),did tag him so just waiting on his response see what he susggests aswell before i end up putting the gun to a tech next week lol

 
ahh, optical. this might explain things, they can be quite the bear to work with.

i've generally preferred external although admittedly i may have sneaked a titan into the akm recently because i didn't like not having precocking that first round after firing auto (and yes i really did buy a titan just to make that small change)

tbh at this point you're talking things like calibration etc (assuming no grease on the sensors as you're planning to check), sadly i'm no help as i've never used perun's stuff.

 
only calibration u can really do with the perun v2 is trigger response bud,ill strip her down give the sensors a clean see if anything maybe one of the wires is cover a sensor slightly will check all that :)

 
only calibration u can really do with the perun v2 is trigger response bud,ill strip her down give the sensors a clean see if anything maybe one of the wires is cover a sensor slightly will check all that :)


could be, maybe the trigger is set too sensitive and it's sometimes not resetting enough to disengage?

 
possibley will see when i get it back together if that is causing an issue

 
Soz m8 was asleep this afternoon

& at work untill 7:00am m8...

Will reply then & edit update

 
ok steps tried sp far cleaned sensors,changed internals back to standard bar mosfet,changed the stickers on the selector plate yet it still continues to happen gah

 
OK regarding safety...

Did you remove the copper plate on the selector plate when affixing sticker for sensor ???

View attachment 69703

What "might" be taking place is the safety cam, (looking like a bloke with a big nose)

the cam or arm is not being pushed back to 12 o'clock when inside the receiver

Safety very likely all works fine on the bench with grip/motor

but when you install it the selector plate is not pushing the safety cam/arm to exactly 12 o'clock

but just a whisker shy say 12:15 ~ 12:30 (taking the safety arm as the little hour hand)

It is a whisker shy of 100% 12 o'clock and the way shit works the actual safety stop is just below trigger's stop

and this just slips under the limit stop of trigger and fires on SAFE

Now if you removed the copper plate you likely lost near 1mm of travel pushing safety arm into position

If you kept the copper tab - then it "should" still operate correctly, hence when had issues with new trigger

I said use old one - which seemed to help

Anyway....

What you might need to do is add a small whisker of material on the left side of selector plate tab

if you have removed the copper plate, then perhaps super glue a capillary straw/pipe like WD40 tube

to left side of selector tab & test - you just want something 1~2mm max glued on to test

(if it works then add a bit of epoxy or glue it properly onto the selector plate)

Basically anything to increase the travel slightly on SAFE so safety arm rises a whisker more to engage it a

If you have the copper plate still on the selector plate, then just add a little line or drizzle of solder to left side

I broke the cm.515 selector getting in/out a few times & used a cheapo one lying around

unfortunately the same thing happened, on safe the gun was very like yours, mostly still able to fire

I drizzled a slither of solder onto the left side of copper plate and the arm then raised fully to stop the trigger

If you haven't removed the copper plate then it doesn't make sense why it isn't working correctly as it was

and you must check the arm itself is not fouling on the Perun inside the box - shouldn't be but check just in case

if it isn't fouling, then chances are for a bit of wear & tear or other reason the selector is not pushing the safety cam

quite enough to the left safe position to ensure the arm itself rises fully

(the oem cheapo orange v2 selector plate I used was made ever so slightly different, the arch was cut a smide over

and so the TM compatible bollox - even with the copper plate fitted, failed to raise the safety 101% correctly like before

a slighter of solder, sticking to the copper plate like shit to a blanket did the trick

or glue a piece of material (plastic strip or say outer insulation sleeve from old wire bit of thin wire)

Now the sporadic firing problem is likely to do with the different sector gear...

It is possible the the optical sensor is not picking all the teeth on the 13:1 sector

be it being jet black, chunkier teeth or just needs to unit shifted a fine minor smidge one way

could be grease on senor, sector rubbing, to do with light not picking up all the teeth

(so cycles another once or twice coz it only read say 14 teeth not 16 if full sector gear)

Also with optical units the gun can be made to cycle if light enters the box

often people go to test a box with box & grip/motor & light enters that tiny pin by trigger

and can make some optical units go nutz & confused & calibration difficult

even then if hold gun upside down towards sun on a sunny day

or shine a bight light at trigger, the light can enter box and cause gun to fire all by itself

yes - optical units can be prone to the odd issues of the sensors incorrectly detecting stuff

I doubt if the colour of the sector really makes much difference, it works by the teeth breaking the beam 16

or whatever it calibrates the gun/sector as...

So most likely the different sector is ever so slightly different, a whisker out of wack picking up varying teeth

so likely need to loosen unit, shift it to right/left slightly & retest if all teeth detect properly

One thing to try is pull the trigger only what it is needed - don't pull it ALLLLLL the way, just enough to fire

as the Perun on ultra full trigger pull can fire, but trigger goes beyond the range of sensor(s) so think trigger is reset

when in fact it has travelled too far on max pull, so that when you release it, it comes back across the sensors

and thinks it is another pull when in fact it is resetting to rest - so gun gets very confused & fires sporadically

on the 516 box there is a casting where you can easily add material to limit the final trigger pull

alas on the 621 box it is not reinforced and doesn't have this material to easily half trigger travel

so alternative method or proper adjustable speed trigger/mod might be needed

but before you do owt shiting unit about, test on half trigger pulls if gun is sporadic (trigger sensor issue)

or if no joy then likely shift unit about to improved the sector sensor detection issue

hope some of this helps

 
i sorted the safety bud changed the screw and safety works fine now

im contemplating just putting it into a tech now tbh starting to lose paitence with it and will end up throwing it against a wall soon haha

 
Well the other alternative is go back to std 18:1 in 621 & RA motor (still quicker)

but to use 13:1 in 516 you need to mod the arc bit on top half of reinforced 516 box

then the 13:1 spur will fit & spin ok

use SHS/RA motor in 621 with 18:1's hoping the Perun will work OK again

then the Cyma motor in 516, with 13:1 after modding arc

both guns will perform "roughly" about the same say 16~17rps on 7.4v lipo sorta thing

bit of fucking about no matter what...

should have just bought your son a set of 16:1's that would go straight in

and you could have left the 621 alone and just used the RA motor in it or kept as is

I blame the kids in the end - Daaaaaaaad - it's not working/fucked

"Well it was running alright when I left it"

bloody kids - cost you a fortune they do

 
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hi bud tried everythig and the perun mosfet has died,the cyma m4 trigger has damaged the trigger sensor so wasnt registering when the trigger pull was properly ending then stopped working completely tried the diagnostic with it outof the box get one beep on trying to enter progrmamming ocassionaly get 2 beeps.so contacted perun about the issue and they are going to replace the mosfet and send out there next gen v2 mosfet aswell for me to try in both cyma gearboxs for them @Sitting Duck perun have also said to sand down the bottom of the trigger where it sits above the optic

 
agreed man i was ready for em to go nope u caused the damge blah blah but nope was the owner that replied and have to say he  was extremely nice and is  posting out the 2 units priority mail on monday

 
yeah that is definately way beyond the standard level of aftersales service you'd expect to find in airsoft.

 
totally bud which was why i contacted them instead of the shop i bought it from as knew they would be like nah thats been cause by you and im glad i did

 
welll the postman just showed up at the door so tonights job will be fitting this beast and boy i cant wait haha

View attachment 70648

 
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welll the postman just showed up at the door so tonights job will be fitting this beast and boy i cant wait haha


What's with the 'Hybrid'? Is it a new version of the Mosfet? If so, got any pics of the unit itself?

 
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