Echo1 P90 firing problems

[FirestormX]

I recently bought two Echo1 P90s off two different people (both were fairly cheap, so I grabbed them), but I've run into two problems with their firing. I went to open it up to take a look, but it seems they need a 3mm allen key, which happens to be the key that is missing from my set, so I need to pick up a new one.

I thought I'd ask here while I get around to buying a new set, so I have an idea of what to look for when I finally sit down with a youtube video and open it up.

The problem with one P90, is that it only shoots in fully automatic, and nothing happens when I switch it to semi. I looked around a little, and from the sounds of it, the P90 will go fully automatic when you pull the trigger all the way, and switching to semi only blocks the trigger from being depressed all the way. There might be a problem with the contact for the trigger not reaching when it's in semi, or something. Does that seem like a likely cause?

The problem with the second P90, is that when I put the battery in and pull the trigger, 99% of the time nothing will happen. But occasionally it will fire once or twice. The trigger depresses fully, the battery is charged fully, I've tried different batteries (including the one that works in the first P90), and there is no sounds (ie a clicking) from the motor.

Aside from reading about gearboxes on ASC, the only experience I have with opening them up and working with them is the upper gearbox of an ICS split...So my knowledge is enough to understand/know how to look up what is suggested to fix it, but I don't have the sense to recognize where the problems are coming from.

Thanks for any advice.

[lurkingknight]

what are you trying to do with the hex key? open the gun or open the gearbox?

Cause you don't need a hex key from the 3 p90s I've owned. You take the butt plate off, you use a phillips screw driver and take the gearbox retaining plate off, you pull the gearbox out.


The trigger on p90s is finicky. A loss of semi auto could mean the first set of trigger contacts are burned/worn and it requires a pull all the way back to the second full auto contacts.

With semi selected, but firing full auto, the cutoff lever could be worn or the semi trigger prongs are too tight, causing the trigger shuttle to get stuck when the cutoff lever tries to hit it to reset it. Or the return spring on the shuttle could be broken or not functioning.

[FirestormX]

I was trying to open the gun with the hex key. It looked like I had to take the side off, but what you said about the butt plate sounds familiar from stuff I've read about the P90. I had assumed the removal was after you split the gun in half - sometimes things don't click when you're reading while tired.

Thanks for the information. The first P90 does not fire at all in semi, so it is probably the first suggestion you had, about the burned/worn first trigger contacts.

[Danke]

Did they copy TM? If so there is a common trigger glitch with that AEG.

[FirestormX]

I believe the echo1 P90 is a clone of the TM.
Would the trigger glitch effect effect the second P90 (pull the trigger in semi or auto, and usually nothing happens, but randomly it will work)?
Actually, now that I've typed that out, it makes sense that it might. Maybe the trigger contact at both semi AND auto is damaged, and only makes contact sometimes?

[Short Round]

For the 1st problem with the full auto, the previous seller might have taped the metal trigger bar. If you split the receivers, look at the lower and there should be a metal bar that goes into the body (is connected to the trigger itself). Disconnect and see if there is tape on it, most likely there will be, and if so remove a couple layers, if there isn't, add a few layers on then.

Make sure the gearbox is aligned perfectly in the body. You also have to have the back plate that holds it into place actually pushing against the gearbox. If you don't you will get issues with the gun's performance.

If these don't work, clean your trigger contacts. That usually solves the problem.

[suzenonest]

With the gun ony firing auto, it's either cut off lever or contacts.

The second gun sounds to be something electrical. Check the motor connections. Check all along the wires too for any small cuts that could cut current

[lurkingknight]

before splitting the body halves, examine functionality of the gearboxes first. The trigger components and cutoff lever generally have everything to do with non functioning semi.

Least destructive investigations first :P

The trigger bar should drop out of the body once the gearbox and receiver are out, so you shouldn't need to split the body.

[FirestormX]

Thanks for the info. I'll take a look at it after work, or this weekend, since I won't need to get off my lazy ass and pick up a new hex set.

If the fix isn't as simple as a bit of tape or a realignment, I'll probably end up taking it in to Select Airsoft/Paintball this weekend to have them take a look.

[FirestormX]

Update: I took the gearboxes out (lurkingknight was right, the echo1 P90 gearboxes come out through the buttplate),

The first problem, with the automatic fire, is just the trigger pull length. It's a simple fix - najohn's tape suggestion should work.

As for the second problem, I didn't notice anything wrong with the wires. I still haven't had time to sit down and actually take apart the mechbox. From what I've read it's a v6 mechbox, so I'll have to sit down with a youtube video, and invest an evening of time into it.

Thanks everyone!

[lurkingknight]

you can adjust trigger pull on the auto trigger by putting tape on the trigger bar that connects the actual trigger to the mechbox trigger mechanism like najohn said, or you can actually bend the copper prongs a little towards the trigger block.

Tape on the trigger bar affects your semi trigger pull as well. But to inspect the electrics all you need to do is take the 3 screws off the trigger assembly on the gearbox. it comes right off and you can check the condition of the semi trigger prongs on top. But if it's an E1, that entire assembly is clear so you can see it. It's the only thing I like about E1 p90s.

[FirestormX]

Sorry for the late update. I want this thread to have a conclusion, in case someone else comes across it (assuming they don't find other threads about this).

The problem with the rarely-firing mechbox was due to the fuse. I just swapped it with a spare one I had, and it fired with every trigger pull.

Both mechboxes fired in full auto most of the time though. I eventually got fed up and just put some tape over the contact for full auto on both mechboxes (I don't plan on gaming them outdoor anyway, and most indoor is only semi), and it was a quick and dirty fix for one mechbox, but not the other.

It seems the one mechbox fires full auto from the semi fire contact (unless I'm not understanding what I'm looking at very well). So now I'm not sure what to do with that mechbox. I'll browse around the forums/google when I have time to sit down with the gun again, to see what I can find on this problem (I have seen posts about P90s only firing in full auto, I just have to pull them up again).

I'll update again if I get it working.

[lurkingknight]

the semi trigger works a lot like v2 and v3 triggers... there's a shuttle that gets pulled into 2 metal prongs to complete the circuit... when the gun cycles, the sector gear has a cam on it that makes the cutoff lever move and tap the shuttle out of the way to break the circuit. Either your cutoff lever is worn out and isn't moving enough (extremely likely since it's the most common thing to die on p90s) or the 2 prongs on your trigger are too close together so they pinch the shuttle too tightly and the lever doesn't have enough force to knock it out of of the trigger to let the spring pull it back to the front.

[deltaspear]

from experience using p90s, its always better to install mosfets early on when using this system.p90 trigger wire sets tend to be rare ( at least here in our place ).if you have the extra funds,its always a good idea to buy a compatible p90 trigger wireset or assembly.it will fix your single or full auto problems.if you want a quick fix,i saw a diy before.when the p90 gbox is removed you will see a thick wire inside the receiver box.thats the part that engages the trigger to the gbox.the end where the gox trigger and the thick wire meets has a spacer placed in between it.the sample that i saw, the wire to gbox trigger contact has at least 4 rolls of electric wire serving as a spacer to make the engagement more responsive.hope this helps

[FirestormX]

Thanks for the info/suggestions guys. =)