On 2019/06/15 1:09 p.m., Bob Engelhardt wrote:
Part of my Habitat volunteering has involved repairing their power
tools.Â* They get Milwaukee tools from the Milwaukee refurb/repair
facility, through a Milwaukee charitable program.

A common problem with these tools is the trigger.Â* Which, of course,
isn't just a switch but is the trigger with 4 control wires as well as
the 2-in, 2-out power lines, a tiny PCB, and the battery connector -
also with control wires.Â* I.e., a nightmare to diagnose and sometimes
ends with us junking the tool (a new switch assembly is much more than
what we pay for the tool).

I was able to definitively diagnose the current tool's problem as a
flakey connector on the signal cable between the battery and the PCB.
The connector appears identical to the ones used for running PC fans
from the MoBo.Â* Like this:
https://i.imgur.com/Q7kfqQG.jpg

I found these contacts that look to be identical to the ones in the tool:
https://www.digikey.com/product-deta...7CT-ND/5287249


I'm puzzled that Molex connectors, if that's what they are, can be so
unreliable.Â* And that Milwaukee would use such unreliable connectors.
Has anybody else seen problems with these connectors?

Bob

BTW - I fixed the tool by removing the contacts from the shell and
soldering them to the pins on the board.


If these connectors are accessible to end users, then it may be as
simple as they are cycled (removed/repluged in) beyond the Molex specs
for life cycles. Usual life cycles are under 100 insertions, however I
can't find the life insertion data on those pins, other than some info
on thirty cycles.

http://www.molex.com/pdm_docs/ps/PS-505261-001-001.pdf

Also these pins are rated at 2A max, any chance they are drawing more
current or running at that current - which shortens the life of course.

Other problems can be in correct crimping tool leading to slight
looseness in the crimp to wire, which ends up as a problem. If the
connector is stressed or can be flexed that will lead to trouble.

I've been using Dow Corning #4 Dielectric Grease on connector pins for a
number of years now (over 20 years) and I find the connections last much
longer and run cooler compared to the same Molex connectors on the
identical equipment.

John