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Flatlander · January 23rd, 2008, 19:28

I purchased a crane stock and several upgrades so I figured I would do a complete overhaul of the mechbox. Background of latest work:

- systema silent head set and cylinder
- gears cleaned, reshimmed and greased
- modify air nozzle
- stock CA spring for CQB use 'til summer (prometheus 110 to be installed in spring)
- G&P crane stock w/ 9.6v 2200 mah w/ deans
- Fuse REMOVED - didn't think it will fit w/ a crane stock...will it somehow???

Rewired my gun to the rear w/ 16g wire from crappy tire - stock wires not quite long enough so I soldered on extention pieces w/ deans. HOWEVER: before I installed the crane stock I tested the above upgrades with the stock mini connector AFTER wiring to the rear (but before extention wires and deans) - result at first was SA only with FA not working (ie. no juice to motor at all in FA). Switched back and forth from SA to FA and FA would spiratically work after a few times. Finally it started working all the time (or seemed to) so I didn't bother looking into it more.

Fast forward to after crane stock installation complete (next day):

Test fired the gun right away and performed absolutely beautifully! Drastic sound reduction, very high ROF, smooth feeding...everything seemed gravy after a couple low caps. Couple days later (today) I go to test fire it a bit more and right away FA does not work (SA still works)...switch back and forth and then I smell something burning! I remove the buffer tube and inspect my solder joints. The POSITIVE wire/joint heated up drastically and melted some of the solder (hence the burning smell). I then hooked the battery back up...behold SA and FA work flawlessly again while going through 3 mags - nothing suspicious happening at the +ve wire junction.

Anyone know what could cause this? It would seem as the trigger assembly IS functioning (wires heating up/melting solder) but the mechbox *shouldn't* be locking up which would create the huge current draw - FA works great when working + no audible indication of motor trying to turn over. So would this mean there is a short after the trigger assembly and before the motor somewhere which is drawing this current? Why semi and no FA sometimes? This is why I'm taking Mechanical Engineering, NOT Electrical

I was planning to redo the wiring to the crane stock - no soldered joints - in a few months when I upgrade to my outdoor spring. I'm hoping not to have to crack open the mechbox 'til then.

Weird note but may/may not be related: I downgraded back to my stock CA spring for CQB this winter (pre-above mentioned upgrades) and when it went back together the selector switch would sometimes be very stiff from moving from safe/SA/FA...getting harder as you progressed to FA. No firing troubles whatsoever until most recent work and the stiff selector problem is still present and speratic.

Thanks guys.

January 23rd, 2008, 19:28	#1
Flatlander Trader rating Join Date: Mar 2007 Location: Edmonton	Weird electrical problem in CA m4 I purchased a crane stock and several upgrades so I figured I would do a complete overhaul of the mechbox. Background of latest work: - systema silent head set and cylinder - gears cleaned, reshimmed and greased - modify air nozzle - stock CA spring for CQB use 'til summer (prometheus 110 to be installed in spring) - G&P crane stock w/ 9.6v 2200 mah w/ deans - Fuse REMOVED - didn't think it will fit w/ a crane stock...will it somehow??? Rewired my gun to the rear w/ 16g wire from crappy tire - stock wires not quite long enough so I soldered on extention pieces w/ deans. HOWEVER: before I installed the crane stock I tested the above upgrades with the stock mini connector AFTER wiring to the rear (but before extention wires and deans) - result at first was SA only with FA not working (ie. no juice to motor at all in FA). Switched back and forth from SA to FA and FA would spiratically work after a few times. Finally it started working all the time (or seemed to) so I didn't bother looking into it more. Fast forward to after crane stock installation complete (next day): Test fired the gun right away and performed absolutely beautifully! Drastic sound reduction, very high ROF, smooth feeding...everything seemed gravy after a couple low caps. Couple days later (today) I go to test fire it a bit more and right away FA does not work (SA still works)...switch back and forth and then I smell something burning! I remove the buffer tube and inspect my solder joints. The POSITIVE wire/joint heated up drastically and melted some of the solder (hence the burning smell). I then hooked the battery back up...behold SA and FA work flawlessly again while going through 3 mags - nothing suspicious happening at the +ve wire junction. Anyone know what could cause this? It would seem as the trigger assembly IS functioning (wires heating up/melting solder) but the mechbox shouldn't be locking up which would create the huge current draw - FA works great when working + no audible indication of motor trying to turn over. So would this mean there is a short after the trigger assembly and before the motor somewhere which is drawing this current? Why semi and no FA sometimes? This is why I'm taking Mechanical Engineering, NOT Electrical I was planning to redo the wiring to the crane stock - no soldered joints - in a few months when I upgrade to my outdoor spring. I'm hoping not to have to crack open the mechbox 'til then. Weird note but may/may not be related: I downgraded back to my stock CA spring for CQB this winter (pre-above mentioned upgrades) and when it went back together the selector switch would sometimes be very stiff from moving from safe/SA/FA...getting harder as you progressed to FA. No firing troubles whatsoever until most recent work and the stiff selector problem is still present and speratic. Thanks guys. Last edited by Flatlander; January 23rd, 2008 at 19:32..